Sciencemadness Discussion Board

Making silane from calcium silicide

John paul III - 23-5-2018 at 10:37

Im looking forward to synthesizing silane from Ca2Si
I realize how dangerous this compound is, and im only going to make a tiny amount, burning it immediately
The process should be analogous to the Mg2Si reaction:
Mg2Si + 4HCl = SiH4 + 2MgCl2
My question is, can I use HNO3, which I have a lot of, or is the hydrochloric acid necessary?

[Edited on 23-5-2018 by John paul III]

unionised - 23-5-2018 at 10:39

HNO3 might oxidise the silane.
Vinegar would probably do the job.

aga - 23-5-2018 at 11:46

Silane spontaneously combusts explosively in air doesn't it ?

unionised - 23-5-2018 at 12:19

Yes.

aga - 23-5-2018 at 12:46

John paul III's photos after he's done this will be awesome.

Looking forward to seeing those photos.

MrHomeScientist - 23-5-2018 at 13:42

How are you making the calcium silicide? Or are you buying it someplace?

MineMan - 23-5-2018 at 14:40

The higher molecular wight silanes are being investigated for propellants and scram jets... as they are liquid and can combust in nitrogen too...

Not much information can be found about them, which makes me think its been quite for a reason... perhaps it does work very well for military fuel...

gatosgr - 25-10-2018 at 13:12

Silane gas is a very nasty chemical.

Silicone fluid are also combustible.

[Edited on 25-10-2018 by gatosgr]

Ubya - 25-10-2018 at 14:53

i can't see why calcium should be better, magnesium silicide is easy to make in the small quantities you need, it's a well known reaction and then magnesium is easier to find and cheaper.
about the acid, maybe HNO3 can oxidise silane directly, or maybe not if diluted enough, anyway it would be a waste of precious nitric acid, HCl or sulphuric acid is ok for this task

phlogiston - 26-10-2018 at 02:39

Interesting, but are you sure the reaction produces silane at all?

IIRC acid hydrolysis of calcium silicides yields polysilicon hydrides and/or siloxene.