Hydrogen ordering in rhenium hydride: anti-CdI2 type structure of ReH0.36

Powder X-ray diffraction experiments of Re–hydrogen system were performed at high pressures and room temperature. Superstructure reflection lines, which were produced by the displacements of rhenium atoms from the hcp lattice points, were observed. This means that hydrogen is incorporated in every second layer along the c-axis of an hcp lattice, which results in an anti-CdI2 type structure. The displacements of rhenium atoms were determined from the relative intensities of these reflection lines.