Crystal structure and magnetic properties of the binary uranium-nickel alloy UNi4

The crystal structure of binary UNi4 was studied from single crystal X-ray diffraction data. This compound crystallises with CaCu5 structure type (space group P6/mmm), with the unit-cell dimension: a = 4.8457(2) (A) over circle, c = 4.0451(2) (A) over circle. This phase belongs to the limited solid solution U1+x Ni5-x with 0.20 < x < 0.33, where U atoms substitute partially Ni on its two crystallographic sites. UNi4 is paramagnetic down to 4.2 K. (C) 2002 Elsevier Science Ltd. All rights reserved.