Diamond anvil cell syntheses and compressibility studies of the spinel-structured gallium oxonitride

The formation conditions of cubic spinel-structured gallium oxonitride have been investigated in situ under high-pressure/high-temperature conditions using a laser-heated diamond anvil cell. As starting materials, a mixture of the end members w-GaN/ß-Ga2O3 in a molar ratio of 3:2 and a gallium oxonitride ceramic derived during pyrolysis from the metallo-organic precursor (Ga(OtBu)2NMe2)2 were used. In the mixture of the end members, spinel-structured gallium oxonitride starts crystallizing at a pressure of 3 GPa and at a temperature of about 1300 °C. The precursor-derived ceramic with predefined bondings reacted completely to the spinel phase, without by-products, at a pressure of 0.7 GPa. For the spinel-structured gallium oxonitride we determined a bulk modulus K of 216(7) GPa using a fixed value of 4 for K'. The spinel-structured gallium oxonitride exhibits a cell volume of 552.9(5) Aring3 at ambient pressure.