Phosphorus hydrides boron halides

The simplest hydrides and halides of boron, silicon, germanium, phosphorus, and arsenic can be decomposed in electric discharges to form... 

Many phosphine-borane complexes Y3P BZ3 have been characterized. They include compounds where Y = alkoxy, alkyl, amino, halide, and hydride groups, and Z = alkyl, halide, and hydride. The stabilities of these complexes vary widely depending on the Lewis acidity and basicity of the boron and phosphorus moieties, respectively. The relative stabilities of Lewis acid-base complexes with BH3 are R3P > R3N > RgAs > R3Sb, but with BF3 the order is R3N > R3P > RsAs > R3Sb. The stabilities of the boron halide complexes of phosphines follow the same order as the amine complexes BI3 > BBt3 > BCI3 > BF3. 

The deposition of boron phosphide by CVD was carried out in a gas flow system by the thermal decomposition of diborane-phosphine mixtures in a hydrogen atmosphere and the thermal reduction of boron tribromide-phosphorus trichloride mixtures with hydrogen (37). The hydrides are thermodynamically unstable at room temperature and decompose rapidly at above 500°C, which tends to promote homogeneous nucleation by pyrolysis in the gas phase. The halides are thermally more stable than the hydrides, and higher substrate temperatures may be used in the thermal reduction process with essentially no gas-phase reactions. At high substrate temperatures, a phosphorus pressure equal to or greater than the vapor pressure of boron phosphide must be present over the substrate surface to maintain the stoichiometry of the deposit. 

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