Magnetic and electrical transport properties of a new compound, NpNiSn, cry
stallizing in the orthorhombic structure of the TiNiSi-type with parameters
a, b and c of 722.8(2), 447.7(1) and 757.1(2) pm, respectively, are report
ed. NpNiSn orders antiferromagnetically below T-N=37 K. Np-237 Mossbauer sp
ectroscopy yields Np moments of 1.53 mu(B). Tbe antiferromagnetic order is
not affected by magnetic field up to 9 T. (C) 1999 Elsevier Science S.A. Al
l rights reserved.