The new phosphide
Hf5Nb5Ni3P5
has been prepared by arc-melting of a pressed stoichiometric mixture
of
HfP, Nb, and Ni. Single crystals suitable for the structure
determination were obtained after annealing in an
induction
furnace at 1350 °C.
Hf5Nb5Ni3P5
crystallizes in the hexagonal space group
P6̄2m (No. 189). The early
transition
metal atoms Hf and Nb are found on three crystallographically different
sites, with refined occupancies of 100% Hf
for the M1, 59.5(4)% Hf and 40.5(4)% Nb for the M2, and
13.1(6)% Hf and 86.9(6)% Nb for the M3 site.
Small
variations of the Hf to Nb ratio are possible, occurring with
significantly different lattice parameters. The early
transition elements form a three-dimensional framework with numerous
M−M (M = Hf, Nb) interactions, including
Ni and P in its trigonal prismatic voids. The differential
fractional site occupancies can be understood on the basis
of the different preferences of Hf and Nb to form M−M, M−Ni, and
M−P bonds. The metallic character is confirmed
by the Pauli paramagnetism experimentally obtained.