Sciencemadness Discussion Board

Detonation Velocity of organic explosive cannot exceed 11 Km/s

Dany - 8-8-2013 at 14:37

In 2 separate interesting article published by Pepekin et al. in 2007 and 2008, they came to an important conclusion that detonation velocity of an organic explosive cannot exceed 11km/s. Thermochemical calculation shows that the limiting velocity of powerful, dense explosive is almost reach. These results are supported by experimental findings on synthesized powerful explosive like CL-20 (Dcj=9.9 Km/s) and dinitrodiazenofuroxane (Dcj=10 Km/s) (these detonation velocity are obtained at crystal density of the two explosive). Also, in a second article, Pepekin et al., found a simple corrolation between impact sensitivity (given as critical pressure Pcr) and the volumetric heat of explosion (which is the density * heat of detonation, in cal/cm3). the correlation is obtained after a study on a number of high explosive with negative oxygen balance. what is interesting is that when extrapolating the Pcr down to 1 bar (ambient atmospheric pressure) a value of 4100 cal/cm3 is obtained which mean that an explosive having this volumetric heat of explosion will spontaneously explode (it cannot exist at normal pressure). comparing the value of 4100 to values of experimentally synthesized explosive yield a value of 3750 cal/cm3 (for dinitrodiazenofuroxane). dinitrodiazenofuroxane is highly sensitive and is considered a primary explosive. The conclusion, in the second article also support the fact that detonation velocity of 11 km/s are the limiting VoD of organic explosives. any increase of volumetric heat of explosion will lead to a compound with higher Dcj but having an extreme sensitivity to external stimilus (having very low Pcr) Although a general correlation is observed between power of an explosive materials and its sensitivity, some compounds may deviate. Octanitrocubane and TKX-50 (recently synthesized by Klapotke et al.) are example of two powerful explosive materials but with moderate sensitivity. These conclusions, don't include homoleptic polynitrogen explosive which in theory are more dense and performs better than organic energetic materials. Unfortunately, apart from pentazolium cation, no synthesis have been reported in open literature for other homoleptic polinitrogen species, due to their high reactivity and positive enthalpy of formation which lead to decomposition to the stable molecular N2.

Any discussion on the topic is welcomed!

Dany.

The two studies of Pepekin et al. can be dowloaded from the following links:

Attachment: Propellant performance of organic explosives and Their Energy Output and Detonation Velocity Limits.pdf (615kB)
This file has been downloaded 1291 times

Attachment: Initiation of Solid Explosives by Mechanical Impact.pdf (174kB)
This file has been downloaded 1191 times

Those are very good articles

franklyn - 8-8-2013 at 21:03

I'm sure PHILOU Zrealone will want to comment on this also.


This may hold valid for a compound made of a carbon containing molecule ,
with conventional chemistry but I would not bet the farm on it. If speed of
reaction is limited so that propagation time does not exceed some benchmark
it does not prevent more energy from being contained in the same volume or
restricting the pressure which might be generated applying means other than
chemical bonding alone. The velocity of detonation is only a property that serves
to indicate overall performance , the detonation pressure being the important
one. The highest speed of sound in any material is that of Beryllium , 13 km/s ,
and that's not an energetic wave , so there is ample room for improvement.
High nitrogen content polymers are sure to exceed any projected cap.

Metastable materials produced by the action of extreme isostatic compression
such as polycarbonyl , or hydrogen metal which as yet remains a gleam in the
eye , are not accounted for as limiting conditions. Polycarbonyl monomer :
is metastable at ambient conditions and is synthesized by compressing liquid
carbon monoxide at pressures exceeding 5GPa , that's 50,000 atmospheres.
www.i-b-r.org/docs/polycarweb.pdf#search="polycarbonyl"
http://pubs.acs.org/doi/abs/10.1021/cm0524446
Carbon dioxide also polymerizes remaining stable so it could be mixed with
nano particles of magnesium and form a very dense explosive compound.
http://prl.aps.org/abstract/PRL/v83/i26/p5527_1
www.pnas.org/content/106/15/6077
www.esrf.eu/UsersAndScience/Publications/Highlights/1999/che...
www.sciencedaily.com/releases/2009/03/090325132901.htm
This same methodology can be applied to force hydrogen into , for example
carbon nano tubes contained as the fuel in an oxygen rich energetic compound.
www.sciencemadness.org/talk/viewthread.php?tid=23314#pid2743...
www.sciencemadness.org/talk/viewthread.php?tid=23314#pid2744...
The included hydrogen is not chemically bonded so does not reduce the energy
available and also does not increase the volume of the matrix. The volume of
explosion however will be.

An explosive device can be built in which aluminum foil which serves as fuel
doubles as the plate of a capacitor so that the dielectric explosive can also
provide some energy in the form of neutralized static electric charge. It is in
practice at least 1000 times less than what is available from the chemical
bonding. This however is scale dependent and there is no reason it cannot
be done at a nanoscale. Ionic salts achieve high density by arrangement in
a lattice of alternating charged ions. Organic molecules known as electrides
form positively and negative charged components. In the same way two
different neutral energetic molecules could be induced to acquire charge much
the same as explosive ionic salts of heterocyclic nitrogen molecules. The binary
compound would in effect be charged as if a capacitor , increasing the energy
content of the material. Some radical energic materials are discussed here _
www.dtic.mil/dtic/tr/fulltext/u2/b088771.pdf
www.dtic.mil/dtic/tr/fulltext/u2/750554.pdf

.

Dany - 9-8-2013 at 01:18

Hello Franklyn,

I don't think that the example of Berylium is true. Although soud speed of beryllium is High (13 Km/s), the metal cannot support detonation wave by its own. so 13 km/s will not be exceeded. A high explosive detonating in beryllium tube for example will send a precursor wave in beryllium tube at soud speed of beryllium ahead of the detonation wave.

Extended CO solid are interesting but the do not offer much energy. in an article entitled "Extended CO Solid- A New Class of High Energy Density Material" the authors mentioned that the polymeric CO solid had an energy comparble to Organic explosive 1-3 Kj/g-nothing special about these polymer- plus they are sensitve and unstable at ambient pressure.

PS: the authors in the mentioned article committed a mistake by saying in page 9 the following "Furthermore,
p-CO could be synthesized in carbon foam to reduce its sensitivity, similarly to the way how highly sensitive TNT was developed into dynamite." Indeed the sensitive explosive is Nitroglycerine and not TNT...

I will added to your exotic HEDM articles, a conference presented by Dr Betsy RICE from the U.S Army Research Laboratory. In this conference Dr RICE talk about energetic material and she mentioned nano diamond as possible new HEDM. nano diamond possess high strain energy, this strain energy can be relased so fast to the surrounding, just like a detonation process.

http://www.youtube.com/watch?v=GftyIvDvqpw

https://e-reports-ext.llnl.gov/pdf/312891.pdf

Dany.

Microtek - 9-8-2013 at 01:55

When I see this kind of statement (the conclusion of the articles mentioned in the first post), I always think of all the times something similar has been said in the past. These spring to mind:

"X-rays will prove to be a hoax."
-- Lord Kelvin, president, Royal Society, 1895


"Radio has no future."
-- Lord Kelvin


"Heavier than air flying machines are impossible."
-- Lord Kelvin

DubaiAmateurRocketry - 9-8-2013 at 02:36

Nice, is it possible for non organic to exceed over 11kms ?

Dany - 9-8-2013 at 03:39

Quote: Originally posted by DubaiAmateurRocketry  
Nice, is it possible for non organic to exceed over 11kms ?


Many theoretical studies mention that Homoleptic polynitrogen explosive, are denser and more energetic than organic explosives. Christe K.O. who synthesized the linear pentazolium N5+ cation predict that this cation detonate at VoD=12 Km/s, indeed doubts still exists in the absence of measured VoD.

Dany.

Ral123 - 9-8-2013 at 04:25

Why is there so much talk on all nitrogen explosives and stuff, when fluorine and aluminium are still not a common part of an explosive molecule. Why we associate nitrogens with energy when some generic oxidations like O2-H2 are more energetic.

Dany - 9-8-2013 at 04:47

Quote: Originally posted by Ral123  
Why is there so much talk on all nitrogen explosives and stuff, when fluorine and aluminium are still not a common part of an explosive molecule. Why we associate nitrogens with energy when some generic oxidations like O2-H2 are more energetic.


Hello Ral123,

It is true that reaction like O2-H2 are very energetic but their detonation speed cannot exceed the VoD of powerful organic explosive. One of the principle cause is their low density even in condensed state. Fluorine as a difluoroamino group (the fluorine analogue of nitro group) are promising explosophoric noiety for HEDM, but their performance slightly increase that of oxygen analogues and are difficult to synthesis. Aluminium and other reactive metals, although very energetic when react with air for example, do not have high VoD. an example of metal containing energetic materials are nano-thermite. nano-thermite possess siognifically higher energy content than organic HEDM, but the detonation speed of nano-thermite is of the order of 3 Km/s. the reason for this slow detonation wave is that the reaction in thermite is limited by slow process such as diffusion and other transport mechanism.

Dany.

TheBackyardScientist - 11-8-2013 at 06:45

"The question is whether you're going to be able to get a long enough look at the material before it realizes its dream of turning into an expanding cloud of hot nitrogen gas."

A nice article about C2N14.
http://pipeline.corante.com/archives/2013/01/09/things_i_won...
If anybody can get the paper here it might state the VOD.
http://onlinelibrary.wiley.com/doi/10.1002/anie.201100300/ab...

Dany - 11-8-2013 at 07:04

Hello TheBackyardScientist,

I know about this compound, beside it's high sensitivity, calculated detonation performance for this compound are Dcj=8960 m/s and Pcj= 339 Kbar. With this detonation parameter C2N14 is inferior even to HMX.
you should look at this paper by Klapotke et al.. This compound is a promising new HEDM having detonation properties equal to epsilon CL-20 and a sensitivity close to TNT

http://www.sciencemadness.org/talk/viewthread.php?tid=25484

Dany.

Attachment: C2N14- An Energetic and Highly Sensitive Binary Azidotetrazole.pdf (403kB)
This file has been downloaded 1217 times



[Edited on 11-8-2013 by Dany]

PHILOU Zrealone - 20-8-2013 at 14:07

Hi Franklyn and all the others :D,

I found those two articles interesting but I find that some things are a bit categorical and that they make maybe too fast conclusions...on a little amount of chozen molecules... not counting the fact that they disgard two of them saying that the reason is not clear why they behave so bad in their predictions...pretexting the probable influence of the OB.

To my feeling with chosen molecules you can make the curve go where you want it to go. Maybe it is a pure hazard or a bad luck but I think they missed a lot by taking into account such diverse molecules into too little amount.
By analysing families of compounds one find very different results and I will try to explain this later down this tread.

I think that those articles speaks about propellant and HE but as most of us do know, HE and propellants are not aimed to be the same.Their wished effect and nature of their properties are not meant to be identical...
1°)HE are by nature meant to break and destroy a target... the speed of detonation is very important in that effect mostly by contact or close viccinity to it, the brisance and detonation wave are primordial for those wished properties.
To temper sensitivity one uses additives in a few %. The higher the density the best.
2°)Propellants are meant to propulse a projectile or a recipient (shuttle)...this precludes the use of HE at full detonating power. No shuttle could withdraw the inner detonation wave of a HE...at least without a very hard and heavy armouring what is contradicting with inherent shuttle design principle. So the power must be strongly tempered by addition of inert materials, dillutors, inhibitors or plasticizers.
Dillution (by air or vaccuum) can simply be the introduction of limited amounts of propellant into the combustion chamber.
Too fast the burning rate and the canon or shuttle may crack/burst/explode or detonate. Too hot a burning flame and pressure and the canon or shuttle will deform or be brought to softening or melting loosing integrity.
This explains why ballistic industry tries to get low temperature burning powders. The powder form allows dillution of the explosive by air but also to give desired shape for specific burning rate/properties and sometimes surface treatment to slow down some process.
One of the main aspect that is not listed in the article on propellants is the need for low molecular weight output products (exhaust)...thus hydrogen is usually a must in those explosives. H2 is the best exhaust molecule, then comes HF, H2O, CO and N2, O2 and at least CO2 what is eavier and has the lowest quadratic speed. In fact H2 can be used to dillute up to 5 times a mix of H2 and O2 without arm...it reduces the risk of detonation, and increases the specific impulse what is not mentionned also into the article and stil a major aspect of the rocketry theories. NH3 and N2H4 are very good because they are hydrogen carriers and poduces some H2, N2 in the exhaust they are also more handelable than H2 in a tinier volume (less eavier tank, less insulation needed) thus more aerodynamic shuttle... Carbon containing molecules are less interesting (except maybe methane because of its hydrogen content) because lower Specific Impulse are acheived.

Long time ago I had the feeling and good intuition (by compulsing explosive stuffs databases) that hydrogen-free explosives was a way to acheive higher VODs and here they explain why :D ... and this is fine!

The explanation for the insensitivity of TATNB (Triaminotrinitrobenzene) is not only what they exposes but also in great part because of the reaction of transformation into another molecule they speak about what is Benzotrifuroxan... this processus is endothermic and catch a good deal of the impact energy also in the process water is lost what tempers the heat generated...
(-C(-NH2)=C(-NO2)-)3 <--> (-C(=NH)-C(=N(O)-OH)-)3
(-C(=NH)-C(=N(O)-OH)-)3 <--> (-C=N-O-N(O)=C-)3 + 3H2O (the underlining is for the junction of the two carbons via sp3 bonding).
As expected the breaking of the aromaticity of the benzen ring (what is stabler) giving exo-benzenic sp2 bonds cost a lot of energy (endothermicity) and gives more unstability to the resulting benzotrifuroxan.

I disagree with their conclusion that when plotting rho*Qmax you get a curve line that implies that above a certain value the compound is too unstable to exist.
All explosives are a compromise between a molecule and its stabler decomposition products... the weakest link between the two is the activation energy barrier... and they don't seem to take this really into account the activation energy barrier is strictly dependant on the molecule structure. Some molecule have a low Ea vs Ed (Energy of decompositon (detonation)) while other have a higher one. A low Ea means a little external energy is needed to go from the explosive molecule to the decomposition products in this process energy is released and if energy dissipation processes is insufficient it can trigger the Ea of several viccinal molecules in an exponential fashion leading to explosion and detonation if the volume is big enough. By kinetic rules the temperature increases the amount of molecules having enough energy to pass the energy barrier and reduces the amount of dissipating energy modes. So Nitroglycerine (propantriol trinitrate ester) sample made by Sobero itself more than a century ago is stil integer and preserved at ambiant temperature. There is a little decomposition happening (statisticaly a little amount of the molecules gather their energy so that a few get high enough energy to pass the energy barrier...while the remaining molecules lower their energy) so this explains that the half life of NG is quite long despite sensitivity (low Ea barrier). This is related to the "PETN halflife of 12 million years" tread you opened...

In their study of initiation of HE they took in account quite exotic molecules with inherently unstable explosophoric groups; the more you get such explosophoric groups into the molecule, the more the power per volume unit and sometimes the higher the density but also, the more unstable the molecule is. The initiation of such unstable "domino" or "card castle" molecules is triggered by the weakest link; very often a diazo group or nitro-nitrite rearrangement.

If you start from known molecules of the same family kind you will notice that the weakest link is generaly of the same kind/order of magnitude.
Then increasing the density, the VOD and the brisance is only a matter of increasing the molecular weight, by increasing the molecular lenght. Franklyn refers to that when implying that polymeric high nitrogen containing molecules might go above the 11km/s cap. Multimerisation paradoxally decreases the sensitivity because the amount of vibrational energy dissipation modes increases (bending, stretching, twisting, rotations, flipping, resonances,...).

To reach the 11km/s detonation wave with CHNO explosives, one would need to be over the 2,3 g/ccm (followig plotting of real HE datas) and over the 2,5 g/ccm (following empirical equations listed hereunder).

VOD (m/s)= 3810*(0,392+d)
P(kbars) = 2,5/1.000.000*d*VOD2
At d=2,5... 11018 m/s are reached and P= 758,7986 kbars.

I know those are approximations but they give ideas about the terra incognita /not wel explored or inexplored regio of >10 km/s VOD explosives.
Real data ploting gives more VOD dependance to density to display a slope of 4285 instead of 3810...thus the empirical formula underevaluates apparently the reality...
To reach and surpass 2,3 or 2,5 g/ccm will be hard work but this seems feasible with extended polynitro polyaromatic ring because graphite has a density of 2,35. The planar graphite leaflets (planar polyaromatic) are held together by pi stacking (what is a good way to increase density and lower sensitivity) and introducing some nitrogen and oxygen into the molecule as nitrogroup already increases the density of aromatic compounds by a lot.
By example C6H6 (benzene) has a density of 0,8941 passing to naphtalene (C10H8) you get a density of 1,145...then adding an extracolladed aromatic ring (anthracene C14H10) you go to 1,25...and with tetracene (C18H12) to 1,3. So by iterations you get a fully aromatic ribon.
I suppose you have noticed the already high density of those pure hydrocarbons?...yeah we were all told to school that hydrocarbons float on water :).
I take as an example that familly with two NO2 per aromatic ring. If you consider the para-dinitrobenzene you already get to a density of 1,486 to compare to the density of benzene.
If you consider the density of 1,4,5,8-tetranitronaphtalene, some list it to be 1,8-1,95...to compare with that of naphtalene.
Following you what would be the tendency for 1,4,5,6,9,10-hexanitroanthracene, 1,4,5,6,7,10,11,12-octanitrotetracene, and higher homologues?
Also you have to take into account the increase of oxygen balance at each step passing from the bad dinitrobenzene asymptotically with a high number of colladed aromating rings to slighly better than the OB of TNB. This invariably means more power, more density, higher VOD, higher heat of explosion but not extensively sensitive!


[Edited on 21-8-2013 by PHILOU Zrealone]

[Edited on 21-8-2013 by PHILOU Zrealone]

Dany - 20-8-2013 at 16:03

Reply to PHILOU Zrealone

When you say "HE are by nature meant to break and destroy a target... the speed of detonation is very important in that effect mostly by contact or close viccinity to it, the brisance and detonation wave are primordial for those wished properties." be careful of taking the detonation velocity as a criterion to judge power of explosive. Detonation energy and pressure are more important when talking about brisance.

also you are saying that :"One of the main aspect that is not listed in the article on propellants is the need for low molecular weight output products (exhaust)...thus hydrogen is usually a must in those explosives. H2 is the best exhaust molecule, then comes HF, H2O, CO and N2, O2 and at least CO2 what is eavier and has the lowest quadratic speed. In fact H2 can be used to dillute up to 5 times a mix of H2 and O2 without arm...it reduces the risk of detonation, and increases the specific impulse what is not mentionned also into the article and stil a major aspect of the rocketry theories. NH3 and N2H4 are very good because they are hydrogen carriers and poduces some H2, N2 in the exhaust they are also more handelable than H2 in a tinier volume (less eavier tank, less insulation needed)...Carbon molecule are less interesting because lower SI are acheived" first, the author is treating the case of organic molecule and explosives so no need to mention the propulsion by hydrogen or other inorganic/cryogenic propellant. second, the author is treating the propellant performance in term of accelerating metal plate (explosive material that accelerate metal plate) and not the propellant that we know to burn in rocket chamber and eject gaseous product from the nozzle. In the 2 case the product of reaction are different and depend on the local conditions. Anyway, here's an important article on the "misuse of detonation velocity"

Dany.



Attachment: About the Misuse of the Detonation Velocity for the Characterization of High Explosives.pdf (802kB)
This file has been downloaded 1056 times

AndersHoveland - 21-8-2013 at 00:57

I would guess that a possible way to exceed this limitation might be to use boron compounds with -SF5 groups, possibly even pentaborane mixed with liquefied SF6 under pressure.

Reply to AndersHoveland

Dany - 21-8-2013 at 01:59

Reply to AndersHoveland

it is not true that fluorine and boron containing compound are advantageous over normal C-H-N-O organic explosive for the following reason: the detonation of boron containing explosive generate complex high molecular weight detonation products like BF3 and B2O3 which also have high degree of freedom (more degree of freedom than normal detonation products like CO, CO2 and N2). The result is that these detonation product (BF3 and B2O3) will retain much of the energy of detonation as internal, thermal energy rather than doing mechanical work on the surrounding. The net effect is that you will get higher detonation temperature but the energy contained in detonation product will be available at late time and at high expansion of the detonation product cloud (when the adiabatic exponent cofficient Cp/Cv approach the value of 1.4 down the isentrope). for more information on boron containing explosive see Numerical Modeling of Explosives and Propellants, Second Edition for Charles L. Mader.

Also, energetic materials containing fluorine explosophoric group (e.g., -NF2, -SF5...) shows that they increase little the crystal density when compared to nitro bearing group and that detonation performance is of the order of powerful classical explosive, nothing special.

Dany.


[Edited on 21-8-2013 by Dany]

AndersHoveland - 21-8-2013 at 22:52

Quote: Originally posted by Dany  
the detonation of boron containing explosive generate complex high molecular weight detonation products like BF3 and B2O3, these detonation product (BF3 and B2O3) will retain much of the energy of detonation as internal, thermal energy rather than doing mechanical work on the surrounding. The net effect is that you will get higher detonation temperature but the energy contained in detonation product will be available at late time

That is certainly a factor, but consider this: a tripropellant rocket, burning lithium with fluorine, and using the resulting heat to vaporize excess liquid hydrogen, has a higher specific impulse (is more energetic) than just burning liquid hydrogen with oxygen. In the situation here, the hot boron-containing decomposition products will transfer much of their heat to the nitrogen gas, causing it to expand.

You forgot to mention that H2O, a fairly ubiquitous decomposition product, also absorbs a fairly large amount of energy.

One potential decomposition product is boron oxyfluoride, and its formation may be the most optimal of the possible boron decomposition products, from the standpoint of what gaseous products will occupy the greatest volume. (not sure how much energy the gaseous trimer absorbs before decomposing into the monomer)
Quote: Originally posted by Dany  
energetic materials containing fluorine explosophoric group (e.g., -NF2, -SF5...) shows that they increase little the crystal density when compared to nitro bearing group and that detonation performance is of the order of powerful classical explosive, nothing special.

The fluorine-containing oxidizing groups release much more energy when they are combining with a fuel other than carbon atoms. What this means in practice is that -NF2 groups would add the most energy to organic molecules that already have a high oxygen balance.

The S-F bond is fairly strong, and such a group is only worth having if there is other atoms very preferential for the fluorine to bond to (not carbon).

Generally -NF2 groups are not really practical from a performance perspective because the oxygen in an -NO2 group can form two bonds, whereas a fluorine atom can form only one. Usually there is no shortage of fuel in the molecule and the oxidizing groups are the limiting factor. The formation of a molecule of H2O releases more energy than an HF, and hydrogen atoms are very easy to incorporate into an energetic molecule. -NF2 groups also result in the explosive being more sensitive, though in some cases they can have advantages over nitro groups. For example, two nitro groups on the same carbon tend to be thermally unstable, but if it is a nitro group and a difluoramino group it is very much more thermally stable.

Another possible area to explore may be the use of lithium clusters, of the type found in n-butyl lithium, a fairly common reducing reagent.

[Edited on 22-8-2013 by AndersHoveland]

caterpillar - 22-8-2013 at 00:02

Well, there is at least one crazy idea. What if one will be able to construct a cumulative charge from one molecule? As you, boys, definitely know, jet stream from a cumulative charge may have speed up to 15 km per second. Let's try to imagine chain of microscopic cumulative charges. The first ignites the second and so on. I mean, if it is possible to restrict propagation of a shock wave in some directions at molecular level? If so, the threshold (11 km/s) could be exceeded.

Dany - 22-8-2013 at 01:50

Quote: Originally posted by caterpillar  
Well, there is at least one crazy idea. What if one will be able to construct a cumulative charge from one molecule? As you, boys, definitely know, jet stream from a cumulative charge may have speed up to 15 km per second. Let's try to imagine chain of microscopic cumulative charges. The first ignites the second and so on. I mean, if it is possible to restrict propagation of a shock wave in some directions at molecular level? If so, the threshold (11 km/s) could be exceeded.


You can increase the detonation performance of a particular explosive and this by colliding detonation wave and forming mach wave in the explosive charge, but in this case you have an overdriven detonation. Overdriven detonation are unstable state and will decay back to the normal champan-jouguet state. Anyway, we are talking about organic explosive compositions that can sustain stable detonation wave and exceed 11 km/s.

Dany.

caterpillar - 22-8-2013 at 04:51

But if we may construct such molecular construction, where detonation wave is focusing itself? Such anisotropic medium, where shock wave is not a sphere? What about sandwich-shaped structures? Nano-tubes? What I'm trying to tell is that analysis, based on only brutto- formula of a compound is not very accurate. There is surely some reserves, lying deep in molecular structures. Large molecules may have some unexpected properties. for example, can you predict, if some protein is extremely toxic or absolutely harmless, knowing its formula (or even structure)?

Dany - 22-8-2013 at 05:52

Hello caterpillar,

The only way to increase the detonation performance beyond the normal Champan-Jouguet point of a given explosive is to take the explosive to an overdriven state. This can be accomplished in several way, for example detonating an HMX cylinder in close contact with an TNT cylinder, will cause the TNT to detonate in an overdriven fashion but only for a short run distance, which can be detected using ionizing pin method for measuring detonation velocity. Shock wave shaping is another mean of achieving overdriven detonation like colliding oblique detonation wave or convergent detonation wave. The impact of a high projectile (e.g., metal plate fired from a gas gun) cause an explosive to be in overdriven state. In some case, like the homogenous initiation of liquid explosive (e.g., nitromethane) the shock wave enter the explosive and heat the material at the interface. after a certain time, a detonation wave appear at the boundary and travel in the explosive in overdriven fashion, because the detonation wave is traveling in a medium that has been shocked and warmed by the passage of the first inert shock wave. Our experience with explosives and detonation of energetic shows that a great deal of properties can be predicted based on a few information (e.g, physical state, basic thermodynamics, and an assumed equation of state).

Some high explosive display what we call shock anisotropy. PETN has this property. But shock anisotropy affect the sensitivity of the explosive materials and not the detonation performance.

check this paper for more info on shock anisotropy in PETN

Dany.

Attachment: Shock Wave Initiation of Pentaerythritol Tetranitrate Single Crystals  Mechanism of Anisotropic Sensitivity.pdf (189kB)
This file has been downloaded 1400 times

[Edited on 22-8-2013 by Dany]

AndersHoveland - 22-8-2013 at 09:23

What about using exploding wire filaments throughout the explosive to detonate the mass simultaneously? Or shape propagating hollow channels into the explosive to transmit a high velocity explosive jet? If the detonation is being initiated by a source other than itself, the detonation velocity could potentially be exceeded.

Reply to AndersHoveland

Dany - 22-8-2013 at 09:56

You will always get an overdriven detonation that will decay to stable chapman-jouguet state.

Dany.

caterpillar - 22-8-2013 at 14:17

Hello, Dany, you think in terms of continuous media. Let's open your mind. Assume you have a super-molecular constructor, which is able to construct any molecule (if this one is stable, of course) and any combination of them. What me and Anders trying to say is that some things is possible, if not now, but may be some decades later with tomorrow technology. A micro cumulative charge may generate a jet with velocity higher than 11 km/sec. This jet may initiate the next micro charge and so on. We may get 15 km/sec at macro level. What prevents us to reproduce it at micro level? Only our too thick fingers. If a molecule blows up, their splinters fly at random directions. What is something like a laser effect is possible? A photon hits an activated media and generate two photons, moving at the same direction. What if something like it is possible in case of molecules? A splinter (one atom or some simple molecule like H2O, CO) hits the next molecule of HE and it generates splinters, moving at the same direction? And what has came to my mind just now. There is a way to obtain extremely hi speed of detonation. I read about it some years ago. What about 1000 miles per second? Or more? Detonation may be caused by light, generated during explosion of a molecule. Mixture of Cl2 and H2 blows up, been illuminated with UF beam. And during reaction this mixture generates such beams, which propagate with light velocity and transmit detonation. Detonation, initiated by light is possible in solid or liquid medias too. Well, I suspect that such media would be too sensitive, if one single photon may cause detonation of a molecule with hi probability. But we are speaking about possible ways (eq. pure theory) how to get extremely speed of detonation, but not about its practical realization.

Marvin - 22-8-2013 at 14:42

Light, electric current, nuclear criticality - there are plenty of ways of doing it but I think you are moving outside of what can reasonably be called a detonation wave. A constructed 'lattice' could have copper strips to detonate micro caps throughout the charge, propagation could be a significant percentage of the speed of light but it's not a VoD.

Microtek - 23-8-2013 at 02:54

I agree that these highly speculative methods of achieving VODs above 11 km/s are not really within the boundaries of the article that stated this limit. However, I also think that this limit is quite artificial, and akin to past assertions that eg. the speed of sound could not be exceeded, or that rockets wouldn't work in a vacuum.

It is good statistical practice to not use a fitted model to try to predict beyond the boundaries of said model, and that is exactly what the authors are doing here: They are making a model based on a selection of already synthesized energetic materials, and then try to predict the future from that.
But this only works as long as the initial assumptions and paradigms hold, and we have seem, time and again, that science progresses in leaps and bounds, precisely when a revolutionary discovery is made.

So, in essence I would call this article an entertaining theoretical excercise, but nothing more.

Dany - 23-8-2013 at 04:38

After reading what other member wrote , i would like to give some remarks:

first, the title of the topic is clear regarding the material studied which is organic explosive. Nobody said that, in general 11 km/s cannot be exceeded. As i mentioned above 11 km/s can be achieved and exceeded using homoleptic polynitrogen explosives. Pentazolium cation N5+ is an example (at least theoretical calculation predict a VoD of 12 km/s, no measurement has been made). Anyway, although Dr. Pepekin studied a small sample of explosive to derive his correlation, i can say that many of the compound can be treated as an extrem case of his group. For example, dinitrodiazenofuroxan is the denset and the most energetic of all furazan and furoxan derivatives. As we know, no furoxan derivative reported in the literature can surpass ~9.5 km/s. We also know that all known explosophoric moiety has been used in almost every combination we can imagine and the result shows that VoD is around ~10 km/s. These finding support the conclusion in Pepekin papers that 11 km/s is the limiting value of organic explosives. I believe, that there is some space for increasing VoD beyond 10 km/s if new, exotic organic explosophoric group are discovered (which is not very plausible). Also, As i mentioned in the thread, octanitrocubane is very energetic (VoD~9.8 km/s, Pcj~45 GPa) but with moderate sensitivity, so synthesizing new platonic hydrocarbon with very high heat of formation (>>650-700 kJ/mol) and high crystal density (>2.2g/cm3) may be helpful for exceedind 10 km/s. As it is clear from the literature, explosive scientist are working on high content nitrogen compounds because they are almost convinced that increasing the detonation performance with carbonaceous compound is almost exhausted.

Dany.

[Edited on 23-8-2013 by Dany]

Dany - 21-9-2013 at 07:38

Another evidence that support Pepekin conclusion (that the limited Dcj is arround 11 km/s and that there is a limiting detonation velocity in explosives materials). This time the evidence is from the vibrational frequencies of a particular atom pairs in explosive molecule.

F. E. Walker, Description of a Shock-Wave Velocity Barrier, Propellants and Explosives 6, 15-16 (1981).

Dany.

Attachment: Description of a Shock-Wave Velocity Barrier.pdf (202kB)
This file has been downloaded 830 times

[Edited on 21-9-2013 by Dany]

caterpillar - 21-9-2013 at 12:38

Another simple thing just came to my mind. Assume, we can initiate detonation of the whole piece of explosive in an instant (no matter how: electrical discharge, light beam, jet of protons and so on). In such case pressure in shock wave will be smaller, than in case of, let's say, "natural" detonation, initiated from one small part of explosive. In case of "natural" detonation shock wave is result of interference of shock waves, generated by any particle of explosive. There will be no such interference, if a whole piece goes off in in instant. Therefore, even if some trick to get super speed of detonation is possible, brisance will suffer.

Ral123 - 21-9-2013 at 14:48

Quote: Originally posted by caterpillar  
Another simple thing just came to my mind. Assume, we can initiate detonation of the whole piece of explosive in an instant (no matter how: electrical discharge, light beam, jet of protons and so on). In such case pressure in shock wave will be smaller, than in case of, let's say, "natural" detonation, initiated from one small part of explosive. In case of "natural" detonation shock wave is result of interference of shock waves, generated by any particle of explosive. There will be no such interference, if a whole piece goes off in in instant. Therefore, even if some trick to get super speed of detonation is possible, brisance will suffer.

I've had the idea that casual cheap explosives can have high velocity core, to initiate all the volume of the material at once, but I also feel, the reduced time to complete reaction this way, wont contribute to more efficiency.

Dany - 21-9-2013 at 18:44

Ral123,

the idea of a "cheap explosives can have high velocity core, to initiate all the volume of the material at once" is not true. Putting a high detonation velocity core explosive will set a curved detonation wave in the whole explosive charge. you can imagine this like an inverted cone detonation wave. so no instantaneous detonation. the reaction still need time to complete. this principal is not new, it is known as wave shaping. Plane wave lens used in detonation experiment uses this technique (wave shaping) to set a plan detonation wave in an acceptor charge. generally the Plane wave lens is formed by two cone of high explosive, with the outer cone formed by a "fast" explosive (e.g., HMX-based explosive) relative to the inner cone formed by a "slow" explosive (e.g., baratol). An important conference on wave shaping can be found here:

http://www.dtic.mil/dtic/tr/fulltext/u2/128529.pdf

Dany.

Ral123 - 21-9-2013 at 23:42

May be the idea isn't worth it for most applications. Imagine a 10 tons rock that must be split. A hole is made for dynamite. If the dynamite has high velocity core, more force will try to split the rock at once.
You have access to pretty interesting documents.

franklyn - 22-9-2013 at 19:18

Hydrogen molecules exist in two types with respect to spin state of their electrons. The ratio of spin isomers depends on temperature. It is 3 moles orthohydrogen (parallel spin) to 1 mole parahydrogen (antiparallel spin) at ambient conditions. It is never possible to obtain a sample containing more than 75 % of orthohydrogen because the ortho form is an excited state and has a higher energy than the para form , it is unstable and cannot be gathered. It is possible to obtain pure parahydrogen , hydrogen molecules are almost entirely of the lower energy para state at cryogenic temperatures. A gas of unpaired hydrogen atoms near absolute zero in a very high magnetic field align antiparallel to the magnetic field and do not form into diatomic molecules. Research to produce monoatomic hydrogen entirely of the parallel spin orthohydrogen is ongoing. Recombination of a metastable monoatomic form into molecules releases 10 's of times more energy by weight than conventional energetic chemistry , but at greater volume due to the very low density of hydrogen.

It should be understood that spin is a quantum property which does not involve mass transport or energy transfer so there is no time limitation for transition between states. Spin polarized hydrogen can change orientation without time as a constraint , as it requires no time to do so. This suggests that reaction speed of this type of energetic process has no fundamental limit since the rate is already effectively infinite.

Ultra Cold Methods for Polarized Atomic Hydrogen
http://deepblue.lib.umich.edu/bitstream/handle/2027.42/87438/119_1.pdf?sequence=2

Separation of Water into Its Ortho and Para Isomers
Abstract here _
www.sciencemag.org/content/296/5577/2363
Download PDF
www.sciencemag.org/content/296/5577/2363.full.pdf

.

[Edited on 23-9-2013 by franklyn]

Microtek - 23-9-2013 at 04:30

But even if the spin transition can occur in no time, the actual recombination into molecular hydrogen cannot. So, the energy release will not be instantaneous.

simply RED - 23-9-2013 at 06:22

"Hydrogen molecules exist in two types with respect to spin state of their electrons."

No! With respect to spin state of their PROTONS. Acc to the quantum mechanics H2 molecule has one sigma bonding and one sigma* antibonding orbital.
http://i48.photobucket.com/albums/f221/Corribus/hydrogen_mol...
Of course the electrons occupy the sigma orbital with antiparalel spin and every attempt to excite to sigma* will break the molecule.

watson.fawkes - 24-9-2013 at 03:58

Quote: Originally posted by franklyn  
Research to produce monoatomic hydrogen entirely of the parallel spin orthohydrogen is ongoing.
That paper you posted has nothing to do with "parallel spin orthohydrogen", which is a state of diatomic hydrogen H2 involving alignment of proton spins (as already stated). The paper is about electron spins aligned with an external magnetic field. About the only things they share are hydrogen atoms and spin, in other words, not much.

Primer on ortho- and para-H2: http://en.wikipedia.org/wiki/Spin_isomers_of_hydrogen

PHILOU Zrealone - 1-9-2014 at 11:38

Quote: Originally posted by Dany  
Another evidence that support Pepekin conclusion (that the limited Dcj is arround 11 km/s and that there is a limiting detonation velocity in explosives materials). This time the evidence is from the vibrational frequencies of a particular atom pairs in explosive molecule.

F. E. Walker, Description of a Shock-Wave Velocity Barrier, Propellants and Explosives 6, 15-16 (1981).

Dany.



[Edited on 21-9-2013 by Dany]

I just reread this article and found evidence that the theory simply doesn't hold the line at least it is very insufficient.

They explain the VOD limitation of High Energy Explosive Material at 10,3 km/s (+/- 11 km/s) by the highest vibration of C-H or N-H bond frequency based on Infrared absorption spectra.

Sole problems are that:
1°) any explosive containing C-H or N-H with the same density should then detonate at the same speed not regarding their OB, amount of explosophoric groups or energy content.

2°) non hydrogen explosives like hexanitrobenzen and octanitrocubane should detonate at very low detonations speeds because they only contain C-C, C=C, C-N, N-O, N=O bonds what resonates in IR with very much lower frequencies than C-H or N-H ones...so VOD should be folowing their theory in the range 5-6km/s while they are both practically in the 9-10 km/s range.

They also postulate that:
a)In the detonation proces propagation of the wave is only vibrational and not radiative or electromagnetic in nature.
--> But what is IR by definition...radiative emission/absorption of electromagnetic field.
b)After the wave has passed higher vibrational frequencies may occur...
--> Thus in the detonation products behind the detonation wave...

Dany - 14-9-2014 at 00:45

PHILOU,

this article simply try to explain that detonation velocity of CHNO high explosive is limited by the vibrational frequency of the bond that make up the system. Regardless of the detonation velocity of a specific explosive, a "limiting" value for Dcj is reached which is governed by the vibrational frequency of the atoms. In fact the author didn't said that the 10.35 or 11 km/s cannot be exceeded, he said:

"It is not intended to imply that the barrier cannot be exceeded but rather that there is a significant decrease in energy efficiency as the barrier is exceeded."

The conclusion set by the author about this barrier (like the sonic and thermal barrier explained in the paper) comes from the experimental evidence that until now thousands of organic explosive CHNO explosive have been synthesized but none (until now) can exceed the 10 km/s which make the vibrational frequency barrier hypothesis very likely.

If in the future an organic CHNO, CHN or even CN explosive will exceed the 11 km/s than we will review and critics this hypothesis.

Dany.

chemister2015 - 28-4-2016 at 18:48

Will metallorganic compounds have high VoD? Example (CH3)2Ti(ClO4)2?

In article Propellants, Explosives, Pyrotechnics Volume 37 issue 3 2012 pp. 335-344 VoD is higher 15 km/s.

P.S.: I'm sorry for my English.

Metacelsus - 28-4-2016 at 20:55

How would one even make that compound, let alone isolate it? It looks ludicrously unstable.

a nitrogen rich explosive - 28-4-2016 at 22:13

It would be. Personally, I am working on a complex of tetrammine copper hexamethylene triperoxide diamine perchlorate. The peroxide ion is very uncomfortable with the Cu+ ion, which would make this an extremely sensitive and powerful explosive.

PHILOU Zrealone - 29-4-2016 at 06:04

Quote: Originally posted by chemister2015  
Will metallorganic compounds have high VoD? Example (CH3)2Ti(ClO4)2?

In article Propellants, Explosives, Pyrotechnics Volume 37 issue 3 2012 pp. 335-344 VoD is higher 15 km/s.

P.S.: I'm sorry for my English.

Very interesting. Do you have the article for me or a picture of that page stating 15 km/s.

Usually Metals are a dead weight for explosives and induce lower VOD...see heavy metals primaries have usually VOD <7 km/s and most of the time between 3 and 6 km/s.

PHILOU Zrealone - 29-4-2016 at 06:06

Quote: Originally posted by a nitrogen rich explosive  
It would be. Personally, I am working on a complex of tetrammine copper hexamethylene triperoxide diamine perchlorate. The peroxide ion is very uncomfortable with the Cu+ ion, which would make this an extremely sensitive and powerful explosive.

If you take infos from another poster, at least take the info right!
Cu(2+) not Cu(+)!

a nitrogen rich explosive - 30-4-2016 at 13:04

Sorry Philou...

The famous Hideki Matsumoto said thus:

Just discussing Octonitrocubane and the power this molecule has with a contact of mine! Turns out that the military thinks that the detonation velocity of this compound could be in the neighbourhood of 91Km/sec (over sublight speeds). This would make this compund almost as powerful as a nuclear weapon! WoW the Cubane molecule has apparently 166KCal per mole of energy! I will see what I can come up with on how it is put together!

Dornier 335A - 30-4-2016 at 23:46

Quote: Originally posted by a nitrogen rich explosive  
Sorry Philou...

The famous Hideki Matsumoto said thus:

Just discussing Octonitrocubane and the power this molecule has with a contact of mine! Turns out that the military thinks that the detonation velocity of this compound could be in the neighbourhood of 91Km/sec (over sublight speeds). This would make this compund almost as powerful as a nuclear weapon! WoW the Cubane molecule has apparently 166KCal per mole of energy! I will see what I can come up with on how it is put together!


91 km/s? What a load of rubbish. Octanitrocubane would reach just over 10 km/s if the predicted high density crystal structure could be achieved. Furthermore, the explosive contains just above 8 MJ/kg (~1.7 times as much as TNT) while nuclear weapons like the Tsar Bomba comes in at around 8 TERAjoules per kilogram.
Have you heard about source criticism?

a nitrogen rich explosive - 1-5-2016 at 00:11

Oh, christ no! I was joking!

Someone on this forum a while ago got banned after saying this... I know that this is shit!

Microtek - 2-5-2016 at 03:25

Philou:

I read the paper referenced above (the one with 15 km/s). It is a purely theoretical paper on nitro-functionalized boron containing molecules. Since the molecules are speculative, the densities are difficult to estimate. For this reason, they calculate the detonation parameters at a range of densities (1.3 to 2.0 g/cc), and the model gives very high figures for VOD (and to a lesser degree, Pcj). The paper is written by Klapötke's group, and they note that there are several potential problems with the model.

PHILOU Zrealone - 2-5-2016 at 12:18

Quote: Originally posted by Microtek  
Philou:

I read the paper referenced above (the one with 15 km/s). It is a purely theoretical paper on nitro-functionalized boron containing molecules. Since the molecules are speculative, the densities are difficult to estimate. For this reason, they calculate the detonation parameters at a range of densities (1.3 to 2.0 g/cc), and the model gives very high figures for VOD (and to a lesser degree, Pcj). The paper is written by Klapötke's group, and they note that there are several potential problems with the model.

OK thanks.
I have also a dozen of putative molécules with VOD >10km

a nitrogen rich explosive - 2-5-2016 at 12:24

Can you U2U me some of them for me to evaluate?

MineMan - 2-5-2016 at 12:47

Will a VOD change from 10km/s to 11km/s make a difference? I would think at a certain point that changes in VOD would be negligible. Has anyone performed a test where an EBW was run through the whole length of a product to simulate a very very high VOD ( in the longitudinal direction only though).

CL-20 shows 40% more depth penetration in shape charges than HMX... with only a 400-600m/s difference, but it also has a higher energy density, and crystal density. I am just speculating that at some point, maybe after 10-12km/s a change in VOD won't make that much of a difference, does the equation for Detonation Pressure become irrelevant at that point.

Danny, I know you are a wizard with these kinds of questions...

a nitrogen rich explosive - 2-5-2016 at 13:17

Well, 10km/s to 11km/s is a 10% change... However, there is a point where VoD becomes irrelevant because of the diffusion of energy throughout the object.

Dornier 335A - 2-5-2016 at 13:37

Changes in VoD are certainly never negligible. Detonation pressure is the important parameter in things like shaped charges. It is related to the detonation velocity according to the following formula:

PCJ = ρ DCJ2 / (1 + γ)
where γ is the adiabatic index (~3 for high density solid explosives) and ρ is the loading density.

So small variations in VoD gives large changes in pressure. For example, HMX at max density has about 4% higher VoD than RDX, but 15% higher detonation pressure.

MineMan - 3-5-2016 at 16:05

Donier,

I am wondering though if that equation should have some boundary conditions though? If I put and EBW through the length of the explosive than the VOD would be near the speed of light (assuming the wire explodes at the rate that current travels through it?)

What am I missing here?

careysub - 3-5-2016 at 16:35

Quote: Originally posted by MineMan  
Donier,

I am wondering though if that equation should have some boundary conditions though? If I put and EBW through the length of the explosive than the VOD would be near the speed of light (assuming the wire explodes at the rate that current travels through it?)

What am I missing here?


Could you show your work? This is a somewhat puzzling statement.

Exploding wires are not detonations. They are explosions that develop over time as energy is fed into them, the peak current flow and heating occurring during the early stage of wire plasma expansion.

MineMan - 3-5-2016 at 16:43

I don't have any work to back this up. It is just a thought experiment...

The wire turning into plasma will detonate the explosive simultaneously though, thus making the VOD (in one axis) the same speed of this reaction from the wire. I am presuming....

careysub - 3-5-2016 at 18:08

Bridge wires aren't very long, for practical purposes it is initiation at a point like with other detonators, with the detonation expanding outward as usual.

You can do much better with a slapper detonator (or on an even larger scale an explosive driven flying plate) which will initiate an entire surface simultaneously. This is not "infinite detonation velocity" though - just a whole bunch of initiation points over an entire surface (the limiting case) and the detonation proceeds at normal velocity in a direction normal to the initiation surface.

This is how air lenses are used to arrange for perfect spherical implosions.

MineMan - 3-5-2016 at 18:53

Right bridgewires are not usually that long, and are meant to initiate at a point...but it is certainly possible to make them run through the whole axis of the explosive, which would initiate more surface area than a slapper disk or the such. If that was done, what would the VOD in the longitudinal axis be....

Detcord running through the length of an emulsion cartridge greatly increases the VOD of the emulsion... I would expect and EBW to do the same if it were long enough. I don't know if it would have any practical applications, but it would be interesting to see the results...

Microtek - 3-5-2016 at 22:06

In a traditionally initiated HE, the shock wave gathers strength as it travels through the mass of explosive, much like an avalanche or a laser does. Initiating the mass throughout its length, negates this effect, so I would not be surprised if this would actually diminish the brisance of the explosive in tests such as the plate dent test.

Pulverulescent - 4-5-2016 at 01:19

Quote:
Initiating the mass throughout its length, negates this effect, so I would not be surprised if this would actually diminish the brisance of the explosive in tests such as the plate dent test.

Mineman is correct, Microtek ─ initiation at multiple points, or at all points along an axis would certainly increase brisance of emulsions and the higher VOD of detcord would be expected to contribute to that increase.

PHILOU Zrealone - 4-5-2016 at 11:02

Quote: Originally posted by a nitrogen rich explosive  
Can you U2U me some of them for me to evaluate?

You evaluate my molecules?
When you have already hard time evaluating your own brew ones...:(

clearly_not_atara - 4-5-2016 at 13:00

I think you've excluded from consideration the sulfur-nitrogen derivatives while forgetting that this class of compounds is relatively unexplored (due to toxicity, instability, and difficulty of synthesis). Tetranitro tetrasulfur tetraimide, S4N4(NO2)4 might be particularly explosive, if it can be synthesized at all (draw it by following S8 > S7NH > S6N2H2 >> S4N4H4 and replacing H with NO2).

PHILOU Zrealone - 5-5-2016 at 04:42

Quote: Originally posted by clearly_not_atara  
I think you've excluded from consideration the sulfur-nitrogen derivatives while forgetting that this class of compounds is relatively unexplored (due to toxicity, instability, and difficulty of synthesis). Tetranitro tetrasulfur tetraimide, S4N4(NO2)4 might be particularly explosive, if it can be synthesized at all (draw it by following S8 > S7NH > S6N2H2 >> S4N4H4 and replacing H with NO2).

While interesting idea...theorically, practically it will not be very interesting...

Why? Because replacing all C atoms by S atoms in energetic molecules means that:
-you will eventually increase the density a little what is favourable for detonic parameters
-you will change the high energy providing CO2(g) (8.19 kJ/g) for nearly half that with SO2(g) (4.64 kJ/g)

But S4N4 is a sensitive negative OB with medium power on its own and eventually by making a binary out of it by admixing a positive OB HE...this might lead to something interesting

--> S4N4 / HONH3NO3
--> S4N4 / N2H5NO3
--> S4N4 / NH4C(NO2)3
--> S4N4 / N2H5C(NO2)3
--> S4N4 / HONH3ClO4
--> S4N4 / N2H5ClO4
--> S4N4 / N2H6(ClO4)2
--> S4N4 / C(NO2)4
--> S4N4 / C2(NO2)6

But this should be less interesting than binaries with superfuels based on CxNy like:
-dicyanoacethylene
-hexacyanobenzene
-tricyano-s-triazine (cyanuric tricyanide)
-hexaazidobenzene
-triazido-tricyano-benzene
-cyanuric triazide
-dicyanotetrazole
-dicyanotetrazine

clearly_not_atara - 8-2-2024 at 09:14

It appears that this assertion may have been defeated in an unexpected manner. The novel superhard material tl24-CN2 is reported to have a gravimetric energy density (Hf) greater than RDX:

https://onlinelibrary.wiley.com/doi/full/10.1002/adma.202308...

Since the speed of sound in diamond is 12 km/s, it's likely similar in these superhard nitrides, so if they can be coaxed into detonating, the VoD would necessarily be even higher.

This is an end-run around the OP argument: instead of packing more energy into the molecule, the bulk modulus was instead pushed to an incredible value.

EDIT: The paper also mentions the high-pressure synthesis of the current (inorganic) champion, lithium pentazolate, VoD = 11.3 km/s (calculated).

[Edited on 8-2-2024 by clearly_not_atara]