Sciencemadness Discussion Board - Black Phosphorus

Black Phosphorus

Hydragyrum - 5-5-2009 at 00:25

Hi all,

I hope this is the right place to ask this - if not, apologies!

I am looking to acquire a small amount of phosphorus (black allotrope) just for an element collection - I don't need red or white for this, and I believe the black allotrope is docile enough to have sent by post without problems.

My only problem is: where to find some? I've searched this forum, and also on ebay, with no luck so far. If anybody can point me in the right direction, that would be fine.

I am in Australia, but I think black P will be OK to have sent from overseas... if I can find it.

ScienceGeek - 5-5-2009 at 03:05

Check out this website:
http://theodoregray.com/PeriodicTable/Elements/015/index.s7....

Ask this guy! He will certainly be able to point you in the right direction!
I also recommend taking some time on the website to check out his amazing elements- collection.

Hydragyrum - 5-5-2009 at 03:16

Thanks ScienceGeek, that seems like a good source of info - much appreciated!

smart elements

pantone159 - 5-5-2009 at 16:45

Try this place - I have never ordered anything from them as their prices are very high, but they do have some interesting things, including black P. (0.5 g 0.99998 P for 157 euros).

http://www.smart-elements.com/?
http://www.smart-elements.com/?element=P&arg=show&li...

Hydragyrum - 5-5-2009 at 23:17

pantone159, thanks very much for that link as well - it looks as though they have some nice things there - I'll check it out.

Fleaker - 7-5-2009 at 12:57

Yep, better get it while you can! It's not that easy to make and rather bothersome to recover the expensive reagent used in its synthesis (believe me, I've done it

).

I'm going to have another crack at it sometime soon though.

Saber - 8-5-2009 at 02:16

Black P is rather expencive to buy.
One can make it however, simply use a the apparatus used to produce white P from red P. what is left after the 'distillation' of the red phosphorus is black P. It can be seperated by dissolving the red and white P in chlorine water, leaving the black allotrope.

Hydragyrum - 8-5-2009 at 02:25

The link given by pantone159 sure does have some nice black phosphorus available - about which they say, "On behalf of a research laboratory we offer these extremely rare crystals of pure black phosphorus, which were made by a new process. Black phosphorus can be prepared under low-pressure conditions at 873 K from red phosphorus via the addition of small quantities of other elements."

Seems this 'new process' has been described in the literature - for any interested, please see: Inorganic Chemistry (2007) 46, 4028-35. The article refers to a method for black P production at 873K. Interesting stuff, but €157 is probably too pricey for me

Saber, you posted while I was writing - thanks for the info!

[Edited on 8-5-2009 by Hydragyrum]

not_important - 8-5-2009 at 08:37

Still a newer process, perhaps. The more traitional method, decades old, uses a seed of black phosphorus and some mercury as a catalyst, newer ones use bismuth as a flux or just red phosphorus with temperature cycling under high vacuum.

woelen - 9-5-2009 at 10:04

Quote: Originally posted by Saber

Black P is rather expencive to buy.
One can make it however, simply use a the apparatus used to produce white P from red P. what is left after the 'distillation' of the red phosphorus is black P. It can be seperated by dissolving the red and white P in chlorine water, leaving the black allotrope.

Are you sure this material is black phosphorus. I also did the experiment of making white P from red P and I also obtained some of the black material, but only a very small amount. Total amount of phosphorus I used was 3 grams, and this yielded almost 3 grams of white P. The black remains are less than 50 mg. I however, kept the black remains as well, just to be sure.

I considered this an impurity in the red phosphorus. I have read that making black P requires pressures of 12.000 atmosphere, which only can be achieved in very well equipped labs.

[Edited on 9-5-09 by woelen]

Eclectic - 10-5-2009 at 06:35

http://www3.interscience.wiley.com/cgi-bin/summary/114035122...

http://dx.doi.org/10.1016/j.jssc.2008.03.008

http://pubs.acs.org/doi/pdf/10.1021/ic062192q

Could someone with full access make the articles available for us?

woelen - 10-5-2009 at 09:45

Interesting to read that there also are low-pressure techniques. Indeed, it would be nice if these articles could be made available to us.

Here are some articles

Fleaker - 10-5-2009 at 18:55

I have already attempted the black phosphorus synthesis on numerous occasions. I had a tougher time of it than I thought I would, mainly because I rushed the heating profile and my pressure was 0.5 micron (needed to be lower in my opinion). My impatience there caused poor results.

Here are a few papers I have sitting on my computer from when I tried it. If anyone really wants to see it, I can go ahead and take the time to post a bunch of photos of how I set up to do it. Unfortunately, I failed the synthesis. Now that I have very, very nice PIDs and muffle furnaces and a proper vacuum system for 10^-7 torr, I will definitely be attempting the synthesis again. I just need a free weekend sometime!

I promised the black P synthesis just as well as the Cs and Rb synthesis (which in the case of Cs did work, however, I need to make a larger apparatus from SS316 and quartz). I have 2 new clamshell tube furnaces which I hope to use in my scale up synthesis.

By the way, most likely Saber found Hittorf's phosphorus (violet phosphorus, which looks black finely ground). It could also just be carbon? In any case, it isn't black phosphorus!

Attachment: Black P by gas phase transport.pdf (300kB)
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Attachment: blackphosphorus.pdf (516kB)
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Hydragyrum - 11-5-2009 at 05:35

Thanks for the articles Fleaker. Is that some kind of preprint you've found?

Jdurg - 10-7-2009 at 18:02

Thanks for the articles Fleaker. I passed the information along to a buddy of mine who has that whole apparatus and the funds/ability to conduct the experiment. Hopefully he gets some good results.

Fleaker - 11-7-2009 at 10:12

Well if he doesn't have oxy hydrogen, then he won't have success. Similarly, if he doesn't have ultra high purity red phosphorus, he will also fail.

careysub - 14-6-2016 at 09:52

Here is the paper on preparing black phosphorus using metal catalysts. It is mentioned above, but the paper is not provided.

It is pretty neat. It uses a significant amount of gold (recoverable probably), about $3 worth for 150 mg of P, and requires the use of silica (quartz) ampoules since the transformation temperature is ~900 C.

It would be nice if you could get a screw-seal refractory metal vessel for this, so making and breaking quartz ampoules is not required.

Attachment: lange2007.pdf (339kB)
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Fleaker - 26-6-2016 at 08:10

I think the gold would wet the refractory metal. Molybdenum handles iodine well (indeed, in van arkel de boer apparatus for crystal bar production, it's usually moly-clad inconel 625--spendy!).

I would like to get this done again now that I have some larger roughing pumps and a turbo pump as well as a large programmable box oven.

The ampoules aren't hard to make if you work in narrow diameters and with a Hoke torch. It is blinding work with quartz, but aside from the heat, it's more forgiving than borosilicate.

careysub - 26-6-2016 at 16:25

Quote: Originally posted by Fleaker

I think the gold would wet the refractory metal.

Gold does not wet molybdenum or tungsten unless special preparation is made to do so.

The normal oxide layer prevents wetting so either it must be removed in a reducing atmosphere or a special gold-platinum alloy is required for wetting to occur.

If necessary an oxidation preparation step might be called for (but from what I am reading, not). If the gold is introduced as a nano-powder (precipitated gold) thoroughly mixed any possibility of wetting is probably minimized.

Although ready-made molybdenum parts (threaded tube and end caps) do not seem to exist, molybdenum tube and rod is readily available and is apparently easily worked by common machine tools. Cutting an internal thread in the ends of a tube, and an external one on a rod of matching diameter (perhaps with a little milling to size) would create such a reaction vessel easily enough. Just a matter of some dollars. Expensive no doubt, but not, I think, extravagantly so, since all the materials and methods are readily available commercially

[Edited on 27-6-2016 by careysub]

Fleaker - 27-6-2016 at 08:38

I'm presuming reducing conditions of P vapor prevail in the tube, although whether or not that affects the W or Mo layer remains to be seen. Having run several hundred kilograms of W evaporation coils + boats with gold on them, I can tell you this much, it sure as hell does wet tungsten in vacuum conditions (as is pieces, not H2 reduced), though that might be due to sublimation of the WO3 when in use for PVD.

As an FYI, we routinely de-braze a pretty diverse array of materials (including PtAu brazed materials).

I have a great idea--why don't you test it out. I've already attempted the synthesis in quartz and had some issues with getting the ampoules sealed with CH4/O2 and no issues with H2/O2; I'd be keen to see how it goes for you in an all molybdenum setup! Maybe Juergen can buy the black phosphorus off you this time...

careysub - 27-6-2016 at 14:28

It will be awhile before I get to that on my projects list - it is pretty long at this point (lots of stuff to do in my - eventual - retirement!)

If anyone has any other ideas about a possible container for this reaction. Although the temperatures aren't too extreme really, 650 C, a container that can be hermetically sealed and won't react with at least one of the components is a problem, e.g., anything containing nickel (often used for chemical resistance) seems out of the question since that is used as a gold scavenger.

Fleaker - 29-6-2016 at 06:37

I think fused silica tubing is still the cheapest option...

Making Black Phosphorus

Dan Vizine - 16-8-2016 at 19:29

Black phosphorus, the least reactive, densest and only known semi-metallic allotrope of phosphorus has a limited range of known synthetic methods:

1) synthesis under high-pressure conditions
2) preparation using mercury as a catalyst
3) the bismuth-flux based method.
4) a temperature/ high vacuum cycling process
5) Au3SnP7 method
6) Sn/SnI4 method

1) The synthesis of black P can be traced back to 100 y ago. In 1914 Bridgman first reported a method to convert white P to black P at a moderate temperature of 200 °C and a high pressure of 1.2 GPa within 5–30 min. By melting black P at a temperature of 900 °C and under a pressure of 1 GPa, black P single crystals larger than 5 × 5 × 10 mm3 can be achieved, as reported by Endo S, Akahama Y, Terada S, Narita S (1982) Growth of large single crystals of black phosphorus under high pressure. Jpn J Appl Phys 21(Part 2, No 8):L482–L484. whereas recently it was reported that amorphous red P could be transformed into crystalline black P at 7.5 ± 0.5 GPa even at room temperature.

2) A mixture of 50 g. of distilled, white P and 50 g. of Hg is placed in an ampoule filled with pieces of copper-plated welding rods. At the same time, 0.5 g. of black P, which has been well pulverized beforehand in an atmosphere of N2, is added as seed crystals. The ampoule is fused shut and gently heated until the white P melts. It is then shaken to achieve good mixing. As a result, a layer of seed crystal powder adheres to the newly amalgamated surface of the welding rods. The ampoule is heated in a protective iron tube to 220°C and then, over a period of two days, to 370°C. After a total of eight days, black P forms quantitatively. Its surface sometimes shows traces of white and red phosphorus.
To produce the seed crystals, a small ampoule filled with freshly distilled white P and 30-40 at. % Hg is placed in a furnace preheated to about 370 C. It is left there for three days at this temperature. It is then heated for one day at 380°C, one day at 390 C and three to four days at 410°C. The well-formed spherules of black P can be easily separated from the other material.To extract the crude product from the admixed Hg, the pulverized sample is placed next to a piece or Pb and heated in an evacuated ampoule for several days at 300-450 C. After repeating the process with the re-pulverized sample and fresh Pb, the remaining Hg amounts to about 1 at. %. If gold is used instead of Pb in the second amalgamation the amount of Hg after heating to between 370°C and 440°C is reduced to about 0.5 at. %. The Hg content cannot be further reduced by this or any other known method. The crystals are reported to become wet over a period of days or weeks

3) Black phosphorus single crystals were prepared from a solution of white phosphorus in liquid bismuth.The bismuth is dissolved away with (1:1) HNO3. Brown A, Rundqvist S (1965) Refinement of the crystal structure of black phosphorus. Acta Crystallogr 19(4):684–685. See also: Synthesis and some properties of black phosphorus single crystals Y. Maruyama, S. Suzuki K. Kobayashi, S. Tanuma

4) Black phosphorus can be made from red phosphorus by thermally cycling red phosphorus in a vacuum between 360-400° C. and 200-240° C., whereupon the red phosphorous undergoes an allotropic phase change to black phosphorus. A mere part of the procedure is enough to place it out of reach of reasonable home synthesis. The detailed structure of the apparatus is therefore omitted.

The conversion process of the invention proceeds as follows: The container is charged with amorphous red phosphorus. The charge may be any size and may be a single piece or multiple pieces. The vacuum chamber is then evacuated to a very low pressure, e.g. <1×10-7 Torr, and preferably <1×10-8 Torr. The vacuum is conveniently pulled through exhaust valve in a third chamber. Before initiating thermal cycling it is generally beneficial to purge the apparatus by outgassing the chambers and evaporating volatile impurities from the phosphorus source material. This procedure involves heating to stages 1 and 2 to a temperature above 200° C., e.g. 250° C. or above.The P chamber is heated to a temperature of approximately 200° C., or above, to prevent material being outgassed from condensing on the walls of the vacuum chamber. Heating for several hours is adequate to clean the apparatus. The valve is closed and thermal cycling initiated. Thermal cycling involves heating the red phosphorus container to a temperature above 350° C., and preferably in the range 360-400° C., with a ramp of preferably 5-20° C./min. The red phosphorus is allowed to cool to a temperature below 300° C., and preferably below 250° C., e.g. 200-240° C. The cooling rate may be comparable to, or more rapid than, the heating rate. This completes one cycle. The red phosphorus is thermally cycled in this manner for three cycles or more, at which point the phosphorus undergoes a sharp allotropic phase change from red to black. The change typically occurs after 3-5 cycles but may occur later. During thermal cycling in a vacuum, P4 vapor is constantly emitted from the red phosphorus charge. This vapor is potentially hazardous. As the P4 vapor rises through the second stage it is converted to P2, the less hazardous form. The third stage is provided to condense vapor that is unconverted in the second stage. During the cool phase of the cycle, this vapor passes to the third stage where it is condensed. Material condensed in the condenser is potentially hazardous and can be periodically burned, or the condenser can be removed and cleaned. The allotropic phase change from red phosphorus to black is accompanied by a dramatic decline in the amount of P4 vapor emitted from the charge. The amount (grams) of white phosphorus condensed from the P4 vapor emitted by a 78 gram red phosphorus source is plotted vs. the number of thermal cycles. A drop in condensed white phosphorus after 4 cycles signals the phase change of the bulk of the charge from red to black. The emitted P4 vapor can be monitored by a pressure gauge. This phase change is stable and irreversible under the conditions of the process.

5) Black phosphorus can be prepared under low-pressure conditions at 600 C from red phosphorus via the addition of small quantities of gold, tin, and tin(IV) iodide. Au3SnP7, AuSn, and Sn4P3 were observed as additional phases. Tin(IV) iodide remains unreacted during the preparation process. SnI4 was prepared by mixing tin (12 g, 0.10 mol) and iodine (40 g, 0.16 mol) in toluene (250 mL). The mixture was refluxed for 30 min until the violet color of the iodine disappeared. The hot solution was decanted from the remaining tin. Orange SnI4 crystallized after the mixture was cooled to room temperature. The crude product was recrystallized from toluene and dried over molecular sieves. Black phosphorus was prepared by the reaction of gold (70.5 mg, 0.358 mmol, 99.9%, foil, Chempur), tin (42.5 mg, 0.358 mmol, 99.999%, ingots, Heraeus), red phosphorus (155.2 mg, 5.011 mmol, 99.999+ %, pieces, Chempur), and SnI4 (10.0 mg, 0.016 mmol, recrystallized) in evacuated (10-3 mbar) silica ampules (length 50 mm, inner diameter 8 mm). The starting materials were heated to 550, 600, or 650 C and kept at this temperature for 5-10 days. Side products, grown on top of the bulk material consisting of either Au3SnP7 and Sn4P3 (600 C) or of Au3SnP7 and AuSn (650 C), can be separated mechanically.

5 Alternate) The mineralizer SnI4 was prepared from tin powder (1.2 g, 99.995%, Chempur) and iodine (4.0 g, resublimed, 99.999%, Chempur) in 25 ml toluene. The starting materials were refluxed for approximately 30 m until the violet color of the dissolved iodine disappeared. After decanting the hot solution from the remaining tin the orange crude product was crystallized at room temperature. The crude product was finally recrystallized from toluene and dried over molecular sieve. AuSn was prepared in a sealed evacuated silica ampoule using an equimolar mixture of gold (Heraeus, 499.9%) and tin (Heraeus, 99.999%). A H2/O2 burner was used to melt the starting materials. After homogenization of the product the purity of AuSn was checked by X-ray powder diffraction and the phase-pure starting material was used without further purification. AuSn acts as a binary precursor to accelerate the reaction to the polyphosphide Au3SnP7 at elevated temperatures prior to the transport reaction. Red phosphorus (500 mg, electronic grade, 99.999+%, Chempur) and AuSn (364 mg) were transferred to a silica ampoule of 10 cm length and an inner diameter of 10 mm. Ten milligram of SnI4 was added and the ampoule was evacuated to pressures lower than 10-3 mbar. The sealed ampoule was transferred to a muffle furnace and was placed horizontally in the middle of the furnace chamber. After heating to 673 K within 1 h the temperature was held at that temperature for 2 h. In the following the temperature was raised to 873 K (1 h) and kept constant at this temperature for 23 h. In a next step the temperature was reduced to 773 K applying a cooling rate of 40 C/h and kept at that temperature before the oven was switched off. The ampoule was cooled down to room temperature within 4 h. This procedure results in the formation of black phosphorus with crystal sizes larger than 1 cm. The efficiency of the preparation process can be substantiated by a reduction of the total reaction time and the amount of AuSn to 10 h (holding time at 700 C) and 200 mg, which results in a comparable conversion ratio with slightly smaller (approx. 0.5 cm) black phosphorus crystals. A total conversion of the red to black phosphorus can be achieved by a prolongation of the reaction time to 70 h at 650 C.

6) Black phosphorus can be made using Sn/SnI4 without Au. Red phosphorus (0.5 g), tin (10 mg), and tin iodide (15 mg) were loaded into a partially sealed quartz tube in a glovebox. The tube was 14 cm long, with a 1 cm inner diameter and a 1.4 cm outer diameter. The tube and its contents were evacuated to ca. 4 x 10-3 mbar and sealed with an oxyhydrogen torch while maintaining vacuum within the ampule.We ensured that the ends of the quartz tubes were >0.4 cm and without entrapped gas bubbles; in one experiment, the quartz tube burst because the walls were too thin. (Caution: only perform this synthesis in a well-ventilated area with restricted access as the risk of unanticipated explosions is high because the tube pressure greatly exceeds 1 atm.) The reaction was carried out in a Lindberg Blue three-zone furnace using the temperature profile described by Nilges. We maintained a 60 C temperature differential across the 15 cm tube by inserting insulation between the two zones.

With the increase of temperature a reduction of the crystal sizes was observed compared with the reaction at 600 C. It was shown that phosphorus in form of P4 and P2 fragments is the only transport relevant species out of all starting materials and possible gas-phase molecule in the present case. The very fast growth of black phosphorus within 32.5 h and a small temperature gradient to crystals larger than 1 cm can only be explained by a rapid gas-phase reaction from these phosphorus fragments (mainly P4 and P2) at the reaction temperature.
No other possible transport species like tin iodides, gold iodides, iodine itself, phosphorus iodides or tin phosphides show reasonable transport efﬁciencies at the applied temperature. We have determined the temperature gradient within the ampoule from measurements with an external thermocouple close to the top and the middle of the ampoules and found a gradient of about 45 K at 600 and at 500 K. The exact application of the reported temperature program is important to grow black phosphorus in the presented way. A deviation from the program led to the formation of white or violet phosphorus as the main phase beside only small or no amounts of black phosphorus. Obviously the combination of different minority gas phase species, the majority phosphorus components and some very complex and temperature dependent gas-phase equilibriums are responsible for the fast formation of black phosphorus. More detailed studies of these phenomena are currently underway to achieve a full understanding of the growth mechanism of black phosphorus.

The reported transport reaction led to the formation of large black phosphorus crystals within reasonable short reaction times. It represents a signiﬁcant improvement in preparation time and achievable crystal size compared with traditional methods like mercury catalysis, high-pressure synthesis and bismuth-ﬂux methods. The present method also drastically improves the previously reported low-pressure route to black phosphorus in the overall product amount per reaction and maybe is suitable to bring the compound a little bit more into the focus of materials scientists for electrochemical applications. Now a deﬁned crystalline product is available at very high purity with no additional workup steps necessary, prior to use. Up-scaling to higher product amount is only dependent on the size of the ampoule and furnace. A reduction of the amount of the starting material AuSn and the mineralizer SnI4 is also possible in order to minimize the production costs and to optimize the conversion rate.

Given the parameters, method 6 is the only practical home synthesis of black P. Unless you have Au to spare, in which case method 5 is equally practical. I think I'll try this synthesis next. Again, this won't be done in a short time, some basic skills need investigation. Sealing the quartz tubing will need examination/practice.

Attribution for information in 6) will follow. A special thanks goes to Anginelle, should she ever happen to read this.

[Edited on 17-8-2016 by Dan Vizine]

Oscilllator - 16-8-2016 at 20:04

Sealing the tube in a vacuum sounds extremely difficult. Have you considered doing something like flushing the inside of the tube with (for example) highly pure CO2, and placing a small amount of Lithium oxide in the tube to absorb this CO2, leaving behind a vacuum?

j_sum1 - 16-8-2016 at 22:14

What a great bit of research. Thanks.

Synthesising thorium aint enough for you Dan?

All of this looks well out of my league. Which of the methods do you think you will go for?

MrHomeScientist - 17-8-2016 at 08:11

The thorium isn't even cool yet and already you're moving on to other things! I really admire your enthusiasm.

The bismuth method sounds extremely simple and easily doable, but I haven't read the citations so it may be much more involved. Molten bismuth is easily achievable by anybody.

Dan Vizine - 17-8-2016 at 13:01

I needed a tube furnace project. I built a 2 zone unit and I've never even used it. It was either this or vapor phase deposition of metal crystals. Black P will be a challenge and much more profitable.

The pressure based syntheses can give bulk transformation of large(r) amounts, 80 g or more. The Au/Sn/SnI4 and Sn/SnI4 methods can give crystals up to 1 cm, while those formed in Bi tend to be rather small in comparison. The Hg product is not worth commenting on, as it is clearly a horrible travesty.

PS. For what it's worth, getting silver colored Ba into an ampoule is much harder to do than making thorium or black P.
I still haven't come close to cracking that nut here. Ironically, I'm helping a professor in Fla. to custom design his glovebox to do just that. Some of the mods are truly one-of-a-kind. Each minute source of a reactive contaminate has been identified and a system put in place to address it. Now we'll see if a slight nitrogen level, if oxygen and water are excluded, does anything to a shiny Ba surface.

[Edited on 17-8-2016 by Dan Vizine]

Dan Vizine - 17-8-2016 at 13:53

Quote: Originally posted by Oscilllator

Sealing the tube in a vacuum sounds extremely difficult. Have you considered doing something like flushing the inside of the tube with (for example) highly pure CO2, and placing a small amount of Lithium oxide in the tube to absorb this CO2, leaving behind a vacuum?

Sealing a borosilicate glass tube while under vacuum is not difficult. It proceeds as you might imagine. You heat on side of the tube until it starts to deflect inward, turn 180 degrees & repeat, turn 90 degrees & repeat, turn 180 degrees and repeat. With luck, the central channel has closed already and you just heat more strongly and pull. Use the flame to fuse the channel to a rounded bump. But as I know from about 2 hours worth of experience 20 years ago, and from everyone who has ever done it, that quartz does not act like borosilicate glass at all when you try glassblowing. I'll need to sharpen my skills with quartz.

The chemistry of this is still very poorly understood. Even screwing up the heating cycle can have very deleterious effects. Changing more variables, like adding lithium carbonate, is to be avoided. Ingenious idea for some projects though!

[Edited on 17-8-2016 by Dan Vizine]

Dan Vizine - 17-8-2016 at 14:19

Quote: Originally posted by j_sum1

What a great bit of research. Thanks.

Synthesising thorium aint enough for you Dan?

All of this looks well out of my league. Which of the methods do you think you will go for?

Method 6 is the hands-down winner. Interesting enough, a group using one of our gloveboxes is doing electrical work on exfoliated single layers. It is thanks to one of these researchers that I became aware of the Au-less route. She is, in fact, quoted pretty much verbatim in the warnings given about ampoule integrity and the need for isolation. Interacting with these and other young university researchers is the best part of my job.

careysub - 17-8-2016 at 14:43

Here is a previous thread on this, where I uploaded the original paper about method 6 (Lange, 2007):

http://www.sciencemadness.org/talk/viewthread.php?tid=12196

clearly_not_atara - 17-8-2016 at 15:01

Quote:

Black phosphorus single crystals were prepared from a solution of white phosphorus in liquid bismuth.The bismuth is dissolved away with (1:1) HNO3. Brown A, Rundqvist S (1965) Refinement of the crystal structure of black phosphorus. Acta Crystallogr 19(4):684–685. See also: Synthesis and some properties of black phosphorus single crystals Y. Maruyama, S. Suzuki K. Kobayashi, S. Tanuma

What if a bismuth eutectic alloy were used? The eutectic alloy of bismuth and tin melts at 140 C. Tin forms a phosphide but at low enough temperatures it might be possible to dissolve phosphorus without reaction. Field's metal in particular might dissolve phosphorus, although it may slowly form indium phosphide. The eutectic of bismuth, lead and tin melts below 100 C.

So I think this route is underrated: it does not first of all carry the possibility of explosion, and secondly, it doesn't seem impossible to recycle the bismuth (or alloy) for multiple uses, since it should be converted to the nitrate, which can then be reduced. Even pure bismuth melts as low as 270 C. It forms an auride (ick) and the melting temperature is not appreciably depressed by silver, but eutectics exist with lead and tin which are interesting.

EDIT:

http://iopscience.iop.org/article/10.1143/JJAP.28.1019/meta

[Edited on 17-8-2016 by clearly_not_atara]

Dan Vizine - 17-8-2016 at 17:26

Oops careysub, sorry. Maybe it should be merged?
clearly-not-atara, the goal is not just to make black P, it's to make the largest crystals possible.

j_sum1 - 17-8-2016 at 18:35

Quoting from the related thread...

Quote: Originally posted by Fleaker

Yep, better get it while you can! It's not that easy to make and rather bothersome to recover the expensive reagent used in its synthesis (believe me, I've done it

).

I'm going to have another crack at it sometime soon though.

Ok. Now I'm curious. Fleaker, if you are around, what method did you employ?
I continued reading the thread but could not identify which method you said you were successful in.

Dan Vizine - 17-8-2016 at 18:56

He used method 5. That's why method 6 is a no-brainer, no gold needed, same results or better.

[Edited on 18-8-2016 by Dan Vizine]

MrHomeScientist - 18-8-2016 at 07:07

Let's say I just want to make a small amount of black P for display in my element collection. How does the bismuth method (#3) work? Do you have more details? It sounds exceedingly simple, and could make a nice video that others could try. I have lots of Bi and some white P.

careysub - 18-8-2016 at 07:42

Quote: Originally posted by Dan Vizine

He used method 5. That's why method 6 is a no-brainer, no gold needed, same results or better.

[Edited on 18-8-2016 by Dan Vizine]

Oh sorry, I misread the lead-in sentence to say "with gold". Do you have the actual reference for method 6?

Fleaker - 22-8-2016 at 12:33

I did indeed use gold. It works. I did it in 1 cm quartz tubes with very thick walls and still had I think 2 ampoules out of 8 or so pop on me and I did check them with polarized glass for cracks. I used both a rotary vane/Pirani and diffusion/IC to pull and measure the vacuum. I think after it was pumped down I put the bottom into LN2 and flame sealed the top. It's really alarming to flame seal thick wall quartz as the heat required is rather substantial. I think this was maybe back in 2008 - 2012. I can't remember for sure, I know I got the PDF about it from iamthewaffler and the paper was somewhat fresh off the presses then. He sent me two papers. Those two were the ones I sealed with CH4/O2 not H2/O2 so that seemed to be all the difference

I made the SnI4 also. The gold recovery made a stink of phosphine, I do remember that. I think I boiled it all in HCl then filtered and went to aqua regia before precipitating the gold back with SO2.

If no gold is required, and you're honestly doing this in Pyrex--I'd be willing to give this another go. Dan, I can order in some very heavy wall large diameter pyrex or vycor and try for bigger crystals in my large tube furnace, which is also built like a brick crap house.

MrHomeScientist - 3-12-2016 at 20:45

rgbco on eBay is selling some very beautiful (and very expensive!) samples of black P - http://www.ebay.com/itm/BLACK-PHOSPHORUS-CRYSTALS-15-10-gram...

If nothing else, they qualify as some very Pretty Pictures.

Dan Vizine - 29-12-2016 at 07:36

Quote: Originally posted by MrHomeScientist

rgbco on eBay is selling some very beautiful (and very expensive!) samples of black P - http://www.ebay.com/itm/BLACK-PHOSPHORUS-CRYSTALS-15-10-gram...

I temporarily lost this thread.
Meanwhile, travel demands are currently the worst in my working lifetime. Company grows, US workforce doesn't ==> work more hours every damned month. I feel like I'm stuck in amber.

I went back and reviewed all the posts for info that I may have missed. There were some fine points, details that need clarification.

Fleaker, I must not have explained myself very well. If I gave the impression that I was going to attempt this in borosilicate, sorry. That is not my intention. It couldn't work, Quartz is absolutely needed.

Fleaker, you also made several other statements that caught my eye...
1) "Similarly, if he doesn't have ultra high purity red phosphorus, he will also fail."
I noticed that the syntheses used 99.999+ % red P. Since the products were intended for electronic investigations, it wasn't clear if the UHP was used for this reason or if it was required for a successful reaction. Is your finding that UHP red P is needed for a good synthesis? If so, I'm out of the game before it even begins. I'm finding it difficult to find any red P, let alone UHP.

2) " It is blinding work with quartz, but aside from the heat, it's more forgiving than borosilicate. "
More forgiving in what way?

3) Reading between the lines, I get the impression that you feel that a very good vacuum level, better than a two-stage mechanical pump can provide, is a key to success? Am I correct in this feeling? Again, this is a crucial point to me. I won't have anything but a two-stage pump. This is confusing. It isn't as though we need a vacuum for the vapor transport, because the tubes are actually pressurized.

Other statements that caught my eye...the idea of a refractory metal tube...
This has several hidden implications. How would it be sealed under vacuum? What seal would remain vacuum-tight at the prevailing conditions? How best to deal with the oxidation of the tube exterior? Mo won't be good at these temperatures in air for days in a row. The gold-free variant at least addresses the alloying issue.

Ultimately, I believe Fleaker is right about quartz being the best alternative.

Another statement backs up my pre-existing belief that oxyhydrogen is needed. The failure of the two tubes that were sealed with a C-containing fuel gas in Fleaker's work seems more than coincidental. I read (somewhere) that normal fuel gasses leave surface contaminants and make weaker seals.

The thing that is boggling my mind is the size of the RGBCO and Smart-Element samples. How?? They suggest this was made similarly to the quartz tube procedure (near atmospheric pressure). But the rest of the world makes this stuff by the gram or smaller. And these guys make samples up to 15 grams??

I will tell you some things you won't find in the literature....
a)My friends at Chapel Hill are interested in the electronic applications.
b) They initially bought black P from Smart-Elements when they were selling 1 g and smaller samples years back.
c) When Smart-Elements started advertising these big 10 and 15 g samples, Chapel hill found the material unsuitable for use. They never set out to make their own black P, it was done out of necessity.

So, there is SOMETHING different about these larger pieces. But they clearly ARE NOT amorphous black P, they're highly crystalline. So, ??? I just don't understand....

And finally...I see WHY I lost this thread. It's in "Reagents and Apparatus Acquisition" ??! This thread may peripherally touch on these points, but isn't this a SYNTHESIS topic? If not, I'm posting in the wrong place. Please consider moving this to a more appropriate spot. If this thread isn't meant to be about making black P, only about obtaining materials, I could start "The preparation of black phosphorous" as a new topic in the appropriate spot so that it gets a good volume of creatively useful traffic.

[Edited on 29-12-2016 by Dan Vizine]

Texium - 29-12-2016 at 08:14

Quote: Originally posted by Dan Vizine

And finally...I see WHY I lost this thread. It's in "Reagents and Apparatus Acquisition" ??! This thread may peripherally touch on these points, but isn't this a SYNTHESIS topic? If not, I'm posting in the wrong place. Please consider moving this to a more appropriate spot.

You got it!

Also, I would recommend adding this thread and others that interest you to your favorites list, that way you'll always be able to find them. Just click Add to Favorites at the top left of the thread. Then you'll be able to find them by going to your User Control Panel, and the favorites page.

[Edited on 12-29-2016 by zts16]

Dan Vizine - 29-12-2016 at 08:25

Thank you on both points zts16!

clearly_not_atara - 21-3-2017 at 12:13

Quote: Originally posted by MrHomeScientist

Let's say I just want to make a small amount of black P for display in my element collection. How does the bismuth method (#3) work? Do you have more details? It sounds exceedingly simple, and could make a nice video that others could try. I have lots of Bi and some white P.

I looked into this extensively. The problem really isn't bismuth, it's that red phosphorus will not dissolve in bismuth, so white phosphorus must be used, and crucially, the white phosphorus must be free of red phosphorus, which means you either have to prepare it in the dark or in situ, either version requiring a complex apparatus and far more work than it sounded like initially.

Köpf et al 2014 has better plans. Here is the full paper with pictures. But the use of an evacuated ampoule is highly discouraging.

I am actually wondering if it might be possible to react carbon with phosphates and condense the vapor into a solvent containing tin (II) iodide. Of course there's an awful lot of "solvent" involved but chloroform is much cheaper than black phosphorus. No reason to distill phosphorus twice when it's already produced as a vapor in the first place, right?

It appears the key catalyst is SnI2. However this will disproportionate at room temperature. So the solvent will have to be hot enough to support some concentration of SnI2 at equilibrium. Hopefully this is not *too* hot.

EDIT: SnI2 has exothermic heat of solution in some solvents, including DMF and DMSO, which may be good (or bad):

http://www.sciencedirect.com/science/article/pii/00221902788...

[Edited on 21-3-2017 by clearly_not_atara]

Fleaker - 28-3-2017 at 07:04

Quote: Originally posted by Dan Vizine

Quote: Originally posted by MrHomeScientist

rgbco on eBay is selling some very beautiful (and very expensive!) samples of black P - http://www.ebay.com/itm/BLACK-PHOSPHORUS-CRYSTALS-15-10-gram...

Sorry I didn't see this. I got into car accident few months back and a facility move and bunch of work.

Anyway, when I did this I used gold. I tried with cheap technical red phosphorus and never got any black P with it. I never got very big black P crystals. Was trying some ramping in a box oven, not a tube furnace. I will try the inclined tube furnace one of these years. I do remember when refining the gold for reuse that if I went right into aqua regia with it, there was no phosphine produced.

Kurt sent me some red P that was low grade for me to work with. I just haven't had the time to mess with it.

Quartz is more forgiving in that it doesn't really thermally shock. It also requires a hell of a lot of heat and thick wall quartz tubing is a must due to pressure. I had several explode ampoules explode on me.

Not only is it that it leaves fuel contamination (though most quartz is lean flame), it's more the fact that oxymethane wasn't as hot. I have a MUCH bigger torch (melted 400 g of Pt with it in a pop) so getting the ampoule liquid at one end is no problem!

Go talk to Jack at Technical Glass Products. They're awesome. They even have some sort of pressure advice on their website. You have to get a great seal on the ampoule for it not to explode.

I also was using a rotary vane and diffusion pump. I think I had a Pirani gauge and a cold cathode.

clearly_not_atara - 28-3-2017 at 10:18

Quote:

It also requires a hell of a lot of heat and thick wall quartz tubing is a must due to pressure. I had several explode ampoules explode on me.

I think that's why they were evacuating their ampoules. If anyone can figure out a way to do that at home though I'd be pretty impressed. Maybe you can put a piece of Mg in the ampoule as a gas scrubber? It reacts with both oxygen and nitrogen...