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ScienceHideout
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Sodium Phosphide
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!
hey, if you are reading this, I can't U2U, but you are always welcome to send me an email!
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barley81
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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 )
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AndersHoveland
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Calcium Phosphide
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]
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IrC
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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]
"Science is the belief in the ignorance of the experts" Richard Feynman
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AndersHoveland
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"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".
I'm not saying let's go kill all the stupid people...I'm just saying lets remove all the warning labels and let the problem sort itself out.
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Endimion17
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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.
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AndersHoveland
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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.
I'm not saying let's go kill all the stupid people...I'm just saying lets remove all the warning labels and let the problem sort itself out.
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mr.crow
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That would mean the Greeks discovered phosphorus (or were close) long before the alchemists. Interesting theory
Double, double toil and trouble; Fire burn, and caldron bubble
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watson.fawkes
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| 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.
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ThePhDChemist
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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]
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Lambda-Eyde
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| 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...
This just in: 95,5 % of the world population lives outside the USA
You should really listen to ABBAPlease drop by our IRC channel: #sciencemadness @ irc.efnet.org
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ThePhDChemist
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| Quote: Originally posted by Lambda-Eyde | | 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... |
 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 
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Neil
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Lambda-Eyde
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| Quote: Originally posted by ThePhDChemist |
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
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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.
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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.
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Now you decide what is most likely.
This just in: 95,5 % of the world population lives outside the USA
You should really listen to ABBAPlease drop by our IRC channel: #sciencemadness @ irc.efnet.org
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ThePhDChemist
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IrC
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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.
"Science is the belief in the ignorance of the experts" Richard Feynman
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mr.crow
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| 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 |
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.
|
Interesting, thanks. Greek and Roman technology was based on experience, not on science the way we know it.
ThePhDChemist was banned? Thank Christ!
Double, double toil and trouble; Fire burn, and caldron bubble
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ScienceSquirrel
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| 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.
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Endimion17
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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.
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IrC
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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.
"Science is the belief in the ignorance of the experts" Richard Feynman
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mr.crow
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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
Double, double toil and trouble; Fire burn, and caldron bubble
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Endimion17
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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.
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AndersHoveland
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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).
I'm not saying let's go kill all the stupid people...I'm just saying lets remove all the warning labels and let the problem sort itself out.
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IrC
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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.
"Science is the belief in the ignorance of the experts" Richard Feynman
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AndersHoveland
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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]
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