BIS(TRIPHENYLTIN) CHALCOGENIDES AS CONVENIENT PRECURSORS TO PHASE-PURE BINARY SEMICONDUCTORS

Bis(triphenyltin) chalcogenides, (Ph3Sn)2X (X = S, Se, and Te), were synthesized in good yield from Ph3SnCl and anhydrous Na2X made from elemental Na and X with a catalytic amount of naphthalene in THF. When heated to relatively modest temperatures (above 300-degrees-C) under an inert atmosphere, it is observed that these compounds undergo a series of phenyl migrations in the condensed (liquid) state. This pyrolysis results in the loss of tetraphenyltin and diphenylchalcogen as ''volatile'' byproducts while leaving behind an inorganic powder. These powders are characterized by X-ray diffraction and found to be phase pure and highly crystalline SnS, SnSe, or SnTe. Combustion analysis detects less than 1% carbon contamination after rinsing with common solvents. Scanning electron micrographs show the powders to be polycrystalline agglomerates having platy (SnS and SnSe) or cubooctahedral (SnTe) habits.