Obtained by separation of mixed silanes prepared from magnesium silicide and hydrochloric acid: Stock, Somiesky, Ber. 49, 111 (1916); 54B, 524 (1921); 56B, 247 (1923); Culbertson, US 2551571 (1951 to Union Carbide); prepared by conversion of silane to higher silanes in an ozonizer type of electric discharge: Spanier, MacDiarmid, Inorg. Chem. 1, 432 (1962).