Crystal structure of the ternary silicide ErNi_4.04Si_0.96

The ternary silicide ErNi4.04Si0.96 was synthesized by arc-melting of stoichiometric quantities of the elements, and its crystal structure has been determined using single-crystal X-ray diffraction data. The compound crystallizes in the CaCu5 structure type: hexagonal space group P6/mmm, Pearson code hP6, Z = 1; a = 4.874(3), c = 3.959(2) angstrom, V = 81.5(1) angstrom 3; R1 = 0.0239, wR2 = 0.0503, for 67 independent reflections with I > 2 sigma(I) and eight variables. The erbium and nickel atoms occupy the crystallographic positions 1a and 2c, respectively. The position 3g is occupied by a mixture of Ni and Si atoms. The structure of this silicide represents a packing of bipyramidal units built from nickel and Ni/Si atoms.