Silicon Subfluoride

According to Deville and Troost and Hautefeuille a lower fluoride of silicon is formed when gaseous silicon tetrafluoride is passed over silicon heated to the softening-point of glass and then suddenly cooled. A white, volatile powder is thus deposited, which contains less fluorine than silicon tetrafluoride and reduces permanganate solution; it is supposed to be a derivative of ter- or bi-valent silicon.