Kagutsuchi - 26-9-2015 at 04:43
I was wondering if I put a burning piece of magnesium into hydragen gas, would it yield magnesium hydride?
unionised - 26-9-2015 at 04:54
No.
Or, at least nor at any reasonable pressure.
The hydride decomposes at about 300C
zed - 26-9-2015 at 13:10
Hydrogenation of finely divided Magnesium Powder, in toluene, at elevated temperature and pressure, might work. Seems to me, such a technique has
been reported, in the presence of Sodium Borates, which are reduced by the Magnesium Hydride, to Sodium Borohydride.
AJKOER2 - 29-9-2015 at 06:45
Some words from Atomistry .com on the topic:
"Winkler observed an absorption of gas when magnesium and magnesium oxide were heated in a current of hydrogen. The solid product had an unpleasant
odour, evolved hydrogen slowly in contact with water, and produced water when it was heated in oxygen. Jolibois, by a different method, obtained a
grey powder which much more certainly contained magnesium hydride than Winkler's product. It decomposed at 280° C. with evolution of hydrogen, and 1
molecule of hydrogen was expelled for every atom of magnesium - corresponding to the formula MgH2. Jolibois obtained his product by heating magnesium
ethyl iodide (electrically) to 175° C. Dry ether washed practically all the iodine out of it, and it then, in contact with water, gave off hydrogen
which took fire. "
Link: http://magnesium.atomistry.com/magnesium_hydride.html
My take on this is that heating MgO in H2 produces a hydrogen containing substance, which may be the result of surface chemistry properties of MgO.
See, for example, dscussion at http://pubs.rsc.org/en/content/chapterhtml/2014/bk9781849739...
Assuming impurities in the Mg/MgO, some possibly unfriendly gases as well, be careful. Research list the most common impurities in magnesium oxide as
CaO, Al2O3, Fe2O3, SiO2 and B2O3, where I find the last compound most problematic as it could be a source of boron and boron hydride (?) with the
latter having been characterized as extremely toxic.
[Edited on 29-9-2015 by AJKOER2]
clearly_not_atara - 29-9-2015 at 15:12
Hydrogenation of Mg is catalyzed by anthracene•magnesium - transition metal halide complexes and may also be catalyzed by naphthalene. These allow
the reaction to proceed at ambient pressure.
http://onlinelibrary.wiley.com/doi/10.1002/anie.198008181/ab...
http://www.sciencedirect.com/science/article/pii/03603199879...
chemrox - 29-9-2015 at 16:36
How a dumb-ass question turns into a nifty thread!
Kagutsuchi - 30-9-2015 at 03:47
I'll do a little testing. Boron and sio2 does not react with acetic acid but magnesium does so I'll dissolve some of my mg and check if I have
anything solid. Also, sorry for the silly question, it was evening here and I was tired. And when I'm tired, I do some foolish things once in a while.
[Edited on 30-9-2015 by Kagutsuchi]