Smiles (Comptes rendus, 1902, pp. 5 6 9, 1 549) from the products obtained in the action of hydrochloric acid on magnesium silicide.
Numerous methods have been given for the preparation of magnesium silicide, Mg 2 Si, in a more or less pure state, but the pure substance appears to have been obtained by P. Lebeau (Cornptes rendus, 1908, 146, p. 282) in the following manner.
From the alloy containing 25% of silicon, the excess of magnesium is removed by a mixture of ethyl iodide and ether and a residue consisting of slate-blue octahedral crystals of magnesium silicide is left.
In answer to your inquiry, I have pleasure in sending you a large purple crystal of carbon silicide.