Mechanochemical synthesis of binary phosphorus telluride: Short range structure and thermal properties

A binary phosphorus telluride sample (20 at% Te) was synthesized by mechanochemical solid state reaction from elemental powders. The X-ray diffraction pattern and neutron total structure factor show no detectable Bragg peaks, indicating that the sample is amorphous with respect to X-ray and neutron diffraction. The neutron and X-ray total pair distribution functions show correlation peak arising from P–Te heteropolar bonds in addition to those arising from P–P and Te–Te bonds. The Te–Te bond length is slightly shorter than that in the crystal structure of trigonal tellurium, suggesting a different environment from a polymeric chain structure. The thermal analysis results show that the binary phosphorus telluride is thermally unstable, that is, it decomposes above 200 °C into trigonal tellurium crystals and gaseous phosphorus, where phosphors begins to gasify at a lower temperature than the sublimation temperature of red phosphors.