Thermoelastic equation of state of boron subphosphide B12P2

Compressibility of boron subphosphide B$_{12}$P$_2$ 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 B$_0$ = 192(11) GPa and its first pressure derivative B$_0$′ = 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 $\alpha$ = 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.