Magnesium Hydride, MgH₂

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.

A characteristic spectrum, obtained by high-frequency discharge between magnesium electrodes in hydrogen and observed in sun-spot spectra, has been attributed to magnesium hydride.