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Sodium Phosphide

ScienceHideout - 17-10-2011 at 12:59

I have been looking everywhere for the synthesis of sodium phosphide... just a sample for my lab- maybe make a video on it. I even... used the search function

! I can't find the synthesis withoout using an impossible to find phosphorus compound...

Would decomp. of TSP work? Or could I do something with phosphoric acid?

Thanks in advance!

barley81 - 17-10-2011 at 18:52

No, you can't decompose TSP into sodium phosphide. You'd probably have to use metallic sodium and elemental phosphorus. It very easily hydrolyzes into phosphine (TOXIC!!!) and sodium hydroxide. If you want phosphine gas, get a bit of white P and boil it with sodium hydroxide (look on Woelen's site for details, http://woelen.homescience.net/science, there are also instructions to convert red P to white P )

Calcium Phosphide

AndersHoveland - 17-10-2011 at 23:10

Calcium phosphide can be obtained by intense heating of calcium phosphate with carbon in a covered crucible, or by heating lime together with phosphorous in an iron pipe to a red heat.

The reactions are probably:

Ca3(PO4)2 + (8)C --> Ca3P2 + (8)CO

(6)CaO + (4)P --> Ca3P2 + Ca(PO3)2

Calcium phosphide reacts with water to produce highly poisonous phosphine gas, which will spontaneously ignite upon exposure to air.

Ca3P2 + (6)H2O --> (3) Ca(OH)2 + (2)PH3

Phosphine gas is oxidized by sulfur dioxide at room temperature, the reaction is best done in a chloroform solvent as otherwise the two gases may combust on contact:

(8)PH3 + (6)SO2 --> (12)H2O + P2S6 + P4

[Edited on 18-10-2011 by AndersHoveland]

IrC - 18-10-2011 at 00:41

Quote: Originally posted by AndersHoveland

Calcium phosphide can be obtained by intense heating of sodium phosphate with carbon in a covered crucible, or by heating lime together with phosphorous in an iron pipe to a red heat.

The reactions are probably:

Ca3(PO4)2 + (8)C --> Ca3P2 + (8)CO

(6)CaO + (4)P --> Ca3P2 + Ca(PO3)2

Calcium phosphide reacts with water to produce highly poisonous phosphine gas, which will spontaneously ignite upon exposure to air.

Ca3P2 + (6)H2O --> (3) Ca(OH)2 + (2)PH3

Phosphine gas is oxidized by sulfur dioxide at room temperature, the reaction is best done in aqueous solution as otherwise the two gases may combust on contact:

(8)PH3 + (6)SO2 --> (12)H2O + P2S6 + P4

[Edited on 18-10-2011 by AndersHoveland]

Think you meant to say Calcium phosphate not sodium phosphate. I am so glad my brain is not the only one that does this on SCM while typing late at night.

The only two remotely similar reactions I know of for Na2P are:

Na2P + Cl6 + 2H2 = 4HCl + 2NaCl + P,
Na2P + 2H2 + 3Cl2 = 4HCl + 2NaCl + P.

You need someone good at this like Woelen to say if these reactions can be reversed, which would possibly be a route to Na2P?

From the page below is given Na3P, being not that familiar with Sodium Phosphide I am not sure why Na2P is listed on page 282 of "A Dictionary of Chemical Equations" the source of the two reactions I list above. Nowhere in this book does it indicate any reaction with Na3P in the equation so you will have to research this one. Meaning if Sodium Phosphide is Na3P then what is the name of Na2P?

http://en.wikipedia.org/wiki/Sodium_phosphide

This page leaves me wondering as below 3 the only other phosphide mentioned is NaP. I do not remember if phosphorus has a valence of one but two does not ring a bell for me either so it would take one of the better chemists here to straighten me out on that one. "In addition to Na3P, five other binary compositions of sodium and phosphorus are known: NaP, Na3P7, Na3P11, NaP7, and NaP15."; from the wiki page. My problem is I do not trust wiki completely and am inclined to believe my book as it was a good reference in it's day.

My not trusting wiki too much aside, I do not know why you did not start with google for sodium phosphide to get to the wiki page I link here, as in it is written the following:

"The first preparation of Na3P was first reported in the mid-19th century. French researcher, Alexandre Baudrimont prepared sodium phosphide by reacting molten sodium with phosphorus pentachloride.[4]

8 Na(l) + PCl5 → 5NaCl + Na3P

Many different routes to Na3P have been described. Due to its flammability and toxicity, Na3P (and related salts) are generally prepared in situ. White phosphorus is reduced by sodium-potassium alloy to give the phosphide salt.[5]

The conversion of white phosphorus to the phosphide has been well studied. Phosphorus reacts with sodium in an autoclave at 150 °C for 5 hours to produce Na3P. [6]

P4 + 12 Na → 4 Na3P ".

[Edited on 10-18-2011 by IrC]

AndersHoveland - 18-10-2011 at 01:32

"Na2P" was sometimes used as an early informal chemical abbreviation for disodium phosphate, even finding its way into actual use in equations. In such a case, the "P" may have actually meant phosphoric acid. Such ambiguity may have easily confused the compilers of such a dictionary.

I find it very doubtful that Na2P would have actually meant "disodium phosphide".

Endimion17 - 18-10-2011 at 06:17

I've made it once by joining together white phosphorus and sodium. It's a messy reaction, and the compound produced can also make a mess.

AndersHoveland - 18-10-2011 at 06:27

Modern scientists believe the formula for Greek Fire may have contained calcium phosphide (which ignites on contact with water). The Greeks would have made the ingredient by heating together lime, bones, charcoal. Bones contain a high proportion of calcium phosphate. Lime (calcium oxide) is essentially roasted limestone.

mr.crow - 18-10-2011 at 06:41

That would mean the Greeks discovered phosphorus (or were close) long before the alchemists. Interesting theory

watson.fawkes - 18-10-2011 at 06:53

Quote: Originally posted by mr.crow

That would mean the Greeks discovered phosphorus (or were close) long before the alchemists. Interesting theory

The modern notion of "discovering an element" means isolating it in atomic form. Ancient chemists knew enough about transformation that they could know the presence of something like phosphorus without having isolated it.

An excellent case it point is zinc. The Romans had brass, zinc-copper alloys, without ever having metallic zinc. The smelted zinc-bearing ores directly in molten copper, presumably with charcoal. The zinc ore reduced and immediately dissolved in the molten copper. It wasn't until Paracelsus that humankind had isolated zinc, but it's incorrect to claim that this was the first knowledge of zinc. Rather, it was a new and important understanding of zinc, not new knowledge of its existence.

ThePhDChemist - 18-10-2011 at 14:42

I know you won't believe this, but believe!
I found in supermarket "baking powder" near citric acid, sodium benzoate...
which contains: sodium bicarbonate, sodium diphosphide or sodium diphosphate - can't remember & starch, so this thread is closed...

[Edited on 18-10-2011 by ThePhDChemist]

Lambda-Eyde - 18-10-2011 at 14:55

Quote: Originally posted by ThePhDChemist

I know you won't believe this, but believe!
I found in supermarket "baking powder" near citric acid, sodium benzoate...
which contains: sodium bicarbonate, sodium diphosphide & starch, so this thread is closed...

Yeah, and I found starch containing sodium cyanide, and chocolate bars with 5% added lead acetate for extra sweetness!

I know you won't believe this, but ...no, really. There's no buts here...

ThePhDChemist - 18-10-2011 at 15:02

Quote: Originally posted by Lambda-Eyde

Quote: Originally posted by ThePhDChemist

Yeah, and I found starch containing sodium cyanide, and chocolate bars with 5% added lead acetate for extra sweetness!

I know you won't believe this, but ...no, really. There's no buts here...

You are making comedy, not me. Don't lie please.
When i seen that baking powder i said: "Oh, my god, why sodium diphosphide, isn't it poisonuos and unhealthy, this is first time i see this, but i did".
Please wait a couple days until i post a picture, then say something

Neil - 18-10-2011 at 15:10

Lambda-Eyde - 18-10-2011 at 15:30

Quote: Originally posted by ThePhDChemist

Yeah... Let's see what the Wikipedia article on sodium phosphide says:

Quote:

It should not be confused with sodium phosphate, Na3PO4.

[...]

Sodium phosphide is highly dangerous releasing toxic phosphine upon hydrolysis, a process that is so exothermic that fires result.

And what about the Wikipedia article on disodium hydrogen phosphate, Na<sub>2</sub>HPO<sub>4</sub>?

Quote:

It is a white powder that is highly hygroscopic and water soluble.[1] It is therefore used commercially as an anti-caking additive in powdered products.

Now you decide what is most likely.

ThePhDChemist - 18-10-2011 at 15:32

2

IrC - 18-10-2011 at 16:58

If I was going to pick PhDChemist as a name I would want to be able to tell the difference between something which makes my shirts stiff and rat poison which would make my whole body stiff as a board for good.

mr.crow - 19-10-2011 at 06:45

Quote: Originally posted by watson.fawkes

Quote: Originally posted by mr.crow

That would mean the Greeks discovered phosphorus (or were close) long before the alchemists. Interesting theory

Interesting, thanks. Greek and Roman technology was based on experience, not on science the way we know it.

ThePhDChemist was banned? Thank Christ!

ScienceSquirrel - 19-10-2011 at 07:11

Quote: Originally posted by mr.crow

Interesting, thanks. Greek and Roman technology was based on experience, not on science the way we know it.

ThePhDChemist was banned? Thank Christ!

A lot of early technology was based on experience and experiment.
It was only when we started to accumulate vast amounts of experience that we began to formulate rules that would predict the results of experiments that we have not performed yet.
Modern brewers have programmes that will predict the strength, colour and bitterness of a beer. But particular blends of malt and hops will produce something that is excellent while others will produce something that is only so so.
Science can help you produce the perfect pint but craft skills and a taste for beer is needed to make something outstanding.

Endimion17 - 19-10-2011 at 07:11

Christ has hardly any credits for that.

On topic. If someone made the actual compound, what was its color? Mine was grayish, maybe a tinge of brown. Disgusting thing to look at, and smell, too.

IrC - 19-10-2011 at 08:20

No doubt you were smelling Phosphine from moisture in the air reacting with your sample.

On a side note I think our bodies are programmed to instinctively revolt at that which is deadly, a survival instinct.

mr.crow - 19-10-2011 at 08:53

Quote: Originally posted by Endimion17

Christ has hardly any credits for that.

Hehe, just trying to vary profanities. Thank Thor wouldn't sound right

My theory (based on evolution) explains why amines, sulfides and short chain carboxylic acids smell so revolting. They are all products of decaying or putrid matter, things that would make us sick. Wolverines can eat 3 day old carcasses no problem, but humans can't even go out for chinese without some distress.

Phosphine won't occur in nature, so how does it smell revolting to us? Maybe it mimics other small molecules and fits in the same receptors. You also know its bad so you want to avoid it even though it is physically not that smelly

Endimion17 - 19-10-2011 at 09:30

I haven't found it to be that revolting. For example, impure carbon disulphide is something that makes me want to run away vomiting, but phosphine is just weird and smelly. I wouldn't be surprised if genetics plays a significant role here, like in the case of PTC.

AndersHoveland - 19-10-2011 at 11:04

Quote: Originally posted by Endimion17

I wouldn't be surprised if genetics plays a significant role here, like in the case of PTC.

I strongly suspect this to be the case, although I have never read anything of such phenomena. For some reason, the smell from both skunks and the ammonium sulfide stink vials does not seem to smell very bad to me, hardly unpleasant, while the people around me express how bad the smells are. I have also eaten chicken roasted over a volcanic vent, which other people found hard to eat because of the impregnated flavor of hydrogen sulfide. To me, all these things merely like boiled eggs, or store-bought lemon juice concentrate. Slightly pungent, but hardly so much as garlic. Skunks smell a little musky in addition, but I just do not understand why it bothers other people so much. It is certainly not the case that I am insensitive to bad smells, many other things are unbearable to me (such as blue cheese).

IrC - 19-10-2011 at 12:29

You are missing the smell receptors for H2S due to genetics. Similarly some people cannot smell cyanide. I can smell both and so well it can be in the PPM, if not into the PPB range.

Actually I love the smell of cyanide. H2S is another story. Buteric Acid is worse still, if the wind is right I am almost retching from a dead animal over a half mile away. Even the slightest trace in meat tastes so bad I want to puke. This in meat others say is just fine. Go figure.

AndersHoveland - 19-10-2011 at 13:40

Quote: Originally posted by IrC

I love the smell of cyanide

Perhaps a perfume or body fragrance should be made.
It would probably be popular amongst the emo crowd.

----------------------------------------------------------------------
I wish my lawn grass was emo, so it would cut itself.

[Edited on 19-10-2011 by AndersHoveland]

IrC - 19-10-2011 at 14:56

So you have never eaten almonds then. Or you can't taste them. Quite possible if H2S does not bother you then you may not be able to smell bitter almonds as well. There was a surplus place in Phoenix that also recovered gold. They had a big room with an air evacuation system which took the air through a special filter setup before it went outside. A huge window was the front wall so if the lone worker keeled over hopefully someone would see it. On one side the mere Sheetrock wall was the back wall of the break room. Against that wall was a crystal water fountain, cooler with a huge water bottle upside down sitting on top. Next to it a Mr Coffee, the water used in it was from this fountain. The Crystal guy replaced to big bottle at least once a week. If I was in there after the bottle had sat there say 3 days, the water was looking a light golden yellow. The coffee tasted slightly almond, actually it was great tasting coffee. I did not go there real often as I knew there had to be HCN leaking around the entire place but they did have great deals on spools of enameled wire and I was building large Tesla coils back then. I often wondered if anyone ever keeled over from the coffee after the place had been closed for the holidays an extra long time but then again I imagine the recovery was also shut down. They lucked out I guess.

Had to google emo. God help us the world is going to crap. These people will be running it? Earth is doomed if they end up in charge.

[Edited on 10-20-2011 by IrC]

AndersHoveland - 19-10-2011 at 20:43

I can smell hydrogen sulfide, but it just does not smell very pungent or bad to me. As for prussic acid, I am really not sure whether I would be able to smell or taste it since I have never tried, and would be a little reluctant to determine the answer.

About emo subculture:

Quote: Originally posted by IrC

Had to google emo. God help us the world is going to crap. These people will be running it? Earth is doomed if they end up in charge.

The "emo" subculture is associated with cutting ones wrists and preoccupies itself with the idea of depression and suicide.

Here is a picture of a typical "emo" youth: http://www.emohaircutstyles.com/wp-content/uploads/2008/09/e...
Note that this is actually a boy.
For more information you might also read: http://www.guardian.co.uk/music/2008/jul/22/russian.emo

Apparently there is much much worse. Just ask RoscoBodine about America's future, and what its young are being taught and exposed to. I could tell you things that go on in Sweden that you would not believe.

Suicides involving H2S and PH3:

At many Japanese schools there are suicide clubs, and there have been many instances of mass suicides amongst youth. Often hydrogen sulfide is employed.

BONIDE Lime Sulfur Spray contains 28% calcium polysulfide.
Liquid bath essence “610HAP” (found in Japan) contains about 20%-25% calcium polysulfides. When either of these is mixed with acid, poisonous hydrogen sulfide is produced.

http://news.bbc.co.uk/2/hi/uk_news/england/2314911.stm

Suicide using aluminum phosphide (used as a fumigant pesticide), is also seen with increasing frequency in parts of India.

[Edited on 20-10-2011 by AndersHoveland]

Aryan - 19-10-2011 at 22:40

forensic stories about aluminum phosphide (and other pesticide) killings

http://members.tripod.com/prof_anil_aggrawal/poiso020.html
http://members.tripod.com/prof_anil_aggrawal/poiso007.html

ScienceSquirrel - 20-10-2011 at 05:20

I do not care what the swastika represents and the font that you are using is not installed on my computer so I cannot see it anyway

Endimion17 - 20-10-2011 at 05:26

Quote: Originally posted by IrC

Had to google emo.

I don't get it. You're new to teh interwebs or what? It was ridiculed back in 2005...

Neil - 20-10-2011 at 06:53

Attached PDF discusses a solvent based process. You would still need P and Na but the reaction heat is lower.

[Edited on 20-10-2011 by Neil]

Attachment: 3397038_MANUFACTURE_OF_A_REACTIVE_TRISOD.pdf (165kB)
This file has been downloaded 515 times

mr.crow - 20-10-2011 at 06:54

Emos are only popular in high school. I went to a nerd school ~10 years ago so there weren't any. Once kids go to University all that bullshit stops, they meet like-minded smart people and don't have to make up a ridiculous subculture to fit in and not get bullied. Emo kids form their own groups to gain acceptance. Its also based on a genre of rock music.

I saw a bottle of calcium polysulfide at the garden store, kind of freaky. You can also get sodium polysulfide as a brown toner for B&W photographs. Looks really nice.

Polysulfide would be great for cleaning up mercury contamination.