new demo idea. Brainstormers needed.

[hermanntrude]

I was talking with our good friend Insane_alien this morning in IRC, and he mentioned to me the fact he synthesised some disilane in the lab. I myself have made silane from magnesium, silica and HCl before, and I was thinking how a good demonstration could be made out of using a hydrocarbon and its silicon-based analogue, showing that the hydrocarbon requires additional heat to reach the activation energy for combustion but silane or whichever silicon-based analogue I choose doesn't.

 

the trouble is ideally i'd like to use analogues, ie methane and silane or ethane and disilane. It's not entirely neccessary but It'd add to the level of comparability.

 

any suggestions on how to make my silane(s) or what to use for my hydrocarbon would be appreciated, or any suggestions on the lab in general...

[insane_alien]

well the easiest way of collecting disilane would be to generate silane as usual(it also generates some disilane and even trisilane but not in useful quantaties) and condense the disilane vapour (it should condense at -14*C) you will need to use a refridgerated coolant(or a really cold day) for this.

 

the yield of disilane varies but i never figured out all the variables.

 

i also still haven't been able to uncover the website i mentioned earlier but you don't really need it i was just messing around with it to see what happens and it'd just complicate the setup.

 

a note on the safety aspect of it, silicon dioxide vapour will be produced, not really a good thing to have glass depositing itself in your lungs have an extractor fan going at all times.

 

also use the proper safety techniques for dealing with explosions although there shouldn't really be any bother if you're sensible about the amounts.

 

and i'm not really saying the safety stuff for hermanns benefit, i know he'll be safer than i was when i did it but its to anyone else who decides they want to give it a shot.

[hermanntrude]

thanks for the info IA. Do you think it's possible to make two substances which are compartable (have the same chain length), given that my lab is fairly old and cheap?

[Horza2002]

I thought the silanes were rather unstable to make and rapidly hydrolysed to silcon oxides in the presence of water...and that only upto the analogue of decane had been made so far?

[insane_alien]

yes, they are incredibly unstable. they spontaneously combust on exposre to air. but they are able to bubble up through water quite easily.

 

long term storage is probably impossible, i tried it but it only lasted a week or two.

 

i'm not sure what the largest silicon analogue is but it ain't a big one.