The Crystal Structure of LaCu6

The crystal structure of LaCu 6 has been determined by an X-ray precession method and Rietveld analysis on powder X-ray diffraction data. The crystal system is monoclinic (space group P 2 1 / c ) with lattice parameters a =5.143 A, b =10.204 A, c =8.144 A and β=91.49°. The unit cell contains four formula units La 4 Cu 24 . The structure is a slight modification of the orthorhombic CeCu 6 structure accompanied by a monoclinic deformation and minor shifts of the atomic positions.