Phosphine and arsine derivatives of monosilane

Abstract

The reaction of silyl iodide with phosphorus, phosphine, arsenic and the arsenides of potassium and mercury has been studied. The compounds P(SiH 3)I 2 and As(SiH 3)I 2 have been isolated and characterized. Both decompose below 100°. Evidence is presented for the existence of the compounds P(SiH 3) 2I, P(SiH 3) 3, P(SiH 3) 4I, As(SiH 3) 2I, As(SiH 3) 3 and As(SiH 3) 4I which, however, have not yet been fully characterized. Silyl iodide forms 1:1 addition compounds with trimethylamine, triethylamine, trimethyl phosphine, triethylphosphine and trimethyl arsine. The first four are only slightly dissociated, but the arsenic compound dissociates readily. Silyl iodide also forms a compound SiH 3I . 1·8 N(CH 3) 3 in its reaction with trimethylamine under pressure. This compound gives a non-conducting solution in acetonitrile, whereas the compounds with one mole of trimethylamine and triethylphosphine give conducting solutions and are therefore salt-like. These results are related to current theories of the formation by silicon of compounds with co-ordination number in excess of four, and of the utilization of d orbitals in bond formation.