Equation of state of InP to 19 GPa

X-ray diffraction experiments have been carried out on InP at room temperature to pressures of 19 GPa. The compression curve for the zinc-blende phase (I) was found to fit the Murnaghan equation up to 10.8 GPa where a transformation to the rocksalt structure was observed. Values for the bulk modulus, ${B}_{\mathrm{I}0}$ and its pressure derivative, ${B}_{\mathrm{I}0{}^{\mathcal{'}}}$, at P=0 obtained by a best-fit procedure to the Murnaghan equation were ${B}_{\mathrm{I}0=76\ifmmode\pm\else\textpm\fi{}4}$ GPa and ${B}_{\mathrm{I}0{}^{\mathcal{'}}=4\ifmmode\pm\else\textpm\fi{}0.2}$. These values are similar to those obtained from precision elastic constant measurements. Analogous parameters for the rocksalt phase (II) were obtained with reference to the transition pressure ${B}_{\mathrm{II}\mathit{t}=130\ifmmode\pm\else\textpm\fi{}10}$ GPa, ${B}_{\mathrm{II}\mathit{t}=1.6\ifmmode\pm\else\textpm\fi{}0.1}$. At 19 GPa a further transformation was observed to a phase which was tentatively identified as \ensuremath{\beta}-Sn-like. Data for these three phases are given and discussed in terms of models for the transitions.