Sciencemadness Discussion Board

lead azide from lead nitrate?

menchaca - 13-3-2003 at 05:39

just a question:

is this reaction posible?


Pb(NO3)2 + 4NH3 ---> Pb(N3)2 + 6H2O

im not sure of it can work or if it doesn´t
i´ve tried to do the redox reaction but im not sure about how. I´d be very pleased if somebody could help me

PHILOU Zrealone - 24-3-2003 at 05:37

Unfortunately it doesn't work that way!

As far as I know

akinmad - 24-7-2003 at 15:38

It is synthesized by passing N2O through molten NaNH2.

:):):D

nice work

Polverone - 27-7-2003 at 22:00

I think I remember reading that before - probably when you posted it last - but I don't know that I commented.

1) Can you make Na2O by decomposition of NaNO3? I think decomposing NaOH or Na2CO3 would require too much heat. Of course NaNO3 thermal decomposition itself isn't all that rapid. Catalyst, maybe? Fe2O3, MnO2?

2) How do you separate the NaOH from NaN3 when the reaction's done?

Nick F - 28-7-2003 at 07:30

But can you think of a metal which has an insoluble azide but a soluble hydroxide..?
I think it's very likely that whatever azide you make will have a heavy hydroxide contamination.
Of course, it could be used for making things such as ammonium azide.

progress report

Polverone - 31-7-2003 at 12:55

NaNO3 seems to be more resistant than anticipated to complete thermal decomposition.

I've made two attempts, both using soup cans as my "crucibles" and a charcoal fire invigorated by an electric fan as the heat source. The first time, the nitrate rapidly melted and was vigorously bubbling within 10 minutes. Within 30 minutes the bubbling had greatly slowed and I assumed that conversion was complete. However, when cooled fragments of the product were added to water, the solution was only weakly alkaline. Addition of acid produced considerable fizzing and some visible NO2 (though not as much as I'd expect if it were pure nitrite). Adding a few fragments of the product to hot charcoal showed that they still had considerable oxidizing power, though not as much as that of NaNO3 alone.

The second time I maintainted the melt at heats ranging from "red" to "orange" for nearly 2 hours, until my charcoal and patience were nearly exhausted. It continued slowly bubbling up until the end, although it too rapidly passed the early "vigorous bubbling" stage. I had to swap cans halfway through as the original can was severely corroded by the melt and was starting to leak.

This batch too showed only weakly alkaline reaction, and again exhibited effervescence with liberation of some NO2 in acid. This is discouraging, because even if my melt contained just 1% or 2% of Na2O I would expect it to give a strongly alkaline reaction in aqueous solution.

It appears that NaNO3/NaNO2 are slow to decompose completely, even well above their published decomposition temperatures. I am wondering if KNO3 would be any different, and if there is any material that might act catalytically to hasten this process.

alwynj48 - 2-8-2003 at 17:31

Hi guys,
Just joined the group and I thought I was the only pyromaniac nut/mad scientist on the planet well apart from a few old friends.

When I was a lad some time ago now, you could buy sodium metal easlily and cheap $20 for 500g. It may be harder these days. I did see some on ebay recently.

Have fun and becarfull Bob

Theoretic - 17-11-2003 at 08:44

Hmmm... Sodium amide is prepared by reacting sodium oxide with liquid ammonia, but maybe gaseous ammonia would work? Also:
1)2CaO + 2NH3 => Ca(NH2)2 + Ca(OH)2
2)Na2CO3 + Ca(NH2)2 => 2NaNH2 + CaCO3
3)2NaNH2 + NaNO3 => NaN3 + 2NaOH + H2O.
OR as already proposed:
2NaNH2 + N2O => NaN3 + NaOH + NH3.
Sodium oxide, I think, could be made like this: CaO + Na2CO3 => CaCO3 + Na2O.
Oh, and by the way, mad scientists are welcome here. Pyromaniac nuts are welcome at E&W. :cool:

Blaster - 17-11-2003 at 14:44

If anyone has prepared NaN3 at home I'd be impressed! Very difficult, but in case it helps its a very common chemical in bio labs where its used as a preservative.

KABOOOM(pyrojustforfun) - 19-11-2003 at 15:21

the NaNO3 method isn't like that. it's:
3NaNH<sub>2</sub> + NaNO<sub>3</sub> <u><sup>&nbsp;175°C</sup></u><s>&nbsp;></s> NaN<sub>3</sub> + 3NaOH + NH<sub>3</sub>
the N<sub>2</sub>O method is done @ 190°C while mp of NaNH<sub>2</sub> is 210°C. thus the yield might be rather low.

Azide via the Hydrazine Route

chemoleo - 28-11-2003 at 20:13

Hmm, let's not forget though that HN3 and the respective salts can be made via the hydrazine route. Hydrazine should be a lot more accessible than metallic sodium, or NaNH2, for that matter.

This works with nitrites, according to

[N2H5+] + HNO2 -> HN3 + [H+] + 2 H2O

This has to be under acidic conditions, where sodium nitrite is added to an acidic solution of hydrazine. By carefully choosing the acid, I think one can then precipitate the azide, and keep the acid anion in solution.

Edit: for instance, using copper hydroxide/oxide/carbonate, and hydrazine sulphate acidified with H2SO4- the resulting CuSO4 is nicely soluble, while Copper azide is not (or so I think)

[Edited on 29-11-2003 by chemoleo]