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Abstract

Ytterbiumhydrides can be synthesized by reaction of ytterbium metal in hydrogen atmosphere above 600 K. The experiments were carried out in the pressure range from 200 to 3200 bar. X-ray investigations on powdered samples and elastic neutron diffraction experiments on deuterated compounds led to a complete structure determination. YbH2.67 is obtained at reaction pressures of 200, 1400 und 3200 bar. In contrast to reports in literature the deuterides crystallize with trigonal symmetry (P (3) over bar 1m, a = 6.344(1) Angstrom, c = 9.002(1) Angstrom, Z = 9) and not in the cubic crystal system. The composition YbD2.67 was additionally checked by chemical analysis. The crystal structure can be described as a close packing of ytterbium atoms (stacking sequence ...ABC...) in which all tetrahedral holes and 2/3 of the octahedral holes are occupied in an ordered manner by hydrogen. Magnetic susceptibility measurements are in agreement with literature data.