Crystallographic parameters of atoms in the single crystals of the compounds RB6 (R=Y, La, Ce, Nd, Sm, Eu, Gd)

The lattice parameters, bond length between rare-earth metals R and boron a toms, intra- and inter-bond lengths between boron atoms and temperature par ameters of constituent atoms in rare-earth hexaborides RB6 (R=Y, La, Ce, Nd , Sm, Eu, Gd) were determined by analyzing integrated X-ray intensities wit h the use of ultra-short wavelength at room temperature. These parameters w ere related to the peculiar physical properties in the compounds. The Einst ein temperature of rare-earth metals in the crystal structure of RB6 (R=La, Ce, Nd, Sm, Eu, Gd) has also been determined by analyzing the temperature dependence of integrated X-ray intensities. Except for EuBdelta, the value is monotonously decreasing with increasing atomic number.