| By treating melts of the composition P2Se5 and P2Se3 with concentrated KOH greenish to colourless crystals of an octahedral habit are obtained having a composition corresponding to K2HPSe3O + 2½H2O. When a solution of K2S is substituted for KOH a thioselenophosphite is crystallised, 2K2S.P2Se3 + 5H2O. When NaOH is used instead of KOH long greenish prisms of Na3PSe3O + 10H2O are obtained. |