Characterization of the new uranium–nickel alloy U10Ni13

The crystal structure of U10Ni13 was investigated from single crystal X-ray diffraction data. This phase, which was formerly designated by the formulation U7Ni9, crystallizes in a new structure type (monoclinic, space group C2/m, a=7.6602(3) Å, b=13.0801(5) Å, c=7.6498(3) Å, β=108.875(2)°). There are 20 uranium atoms in the unit cell, distributed in 8j, 8j and 4i Wyckoff positions and 26 nickel atoms occupying 8j, 8j, 4i, 4i, 2a Wyckoff positions. In the first coordination sphere, the U–U distances range from 2.753(1) to 3.075(2) Å and the U–Ni distance ranges from 2.648(3) to 2.866(3) Å. U10Ni13 does not order magnetically at low temperature.