Thermoelastic equation of state of boron subphosphide B12P2

Abstract

Compressibility of boron subphosphide B₁₂P₂ has been studied under quasi-hydrostatic conditions up to 26 GPa and 2600 K using laser-heated diamond anvil cell and angle-dispersive synchrotron X-ray diffraction. 300-K data fit yields the values of bulk modulus B₀ = 192(11) GPa and its first pressure derivative B₀′ = 5.5(12). It has been found that at ambient pressure the thermal expansion is quasi-linear up to 1300 K with average volume expansion coefficient α = 17.4(1) × 10⁻⁶ K⁻¹. The whole set of experimental p–V–T data is well described by the Anderson-Grüneisen model with δ_T = 6.