X-ray diffraction measurements for solid methane at high pressures

X-ray powder diffraction and Raman scattering experiments for solid methane were carried out at pressures up to 37 GPa and room temperature. The diffraction pattern of phase B at 16.9 GPa is assigned to a cubic lattice with lattice constant of 7.914 Angstrom (B. At the transition from phase B to the HP phase, the pressure-volume curve shows an anomaly without the structural change.