Revisiting a Rare Intermetallic Ternary Nitride, Ni2Mo3N: Crystal Structure and Property Measurements

The intermetallic ternary nitride, Ni2Mo3N, has been synthesized by the ammonolysis of a complexed mixed-metal chloride precursor. This compound crystallizes in the cubic space group P4132 [213] with Z=4 and a lattice parameter of a=6.6340 (2) ?, as determined from powder X-ray and neutron diffraction experiments and the Rietveld refinement of the neutron data collected at room temperature. The refinement converged with Rwp=0.032, Rp=0.025, RI=0.059, and chi2=1.48. Ni2Mo3N assumes a filled beta-manganese structure, ideally consisting of a lattice of corner-sharing Mo6N octahedra in a fivemembered ring arrangement and an interpenetrating net-like lattice of nickel atoms which occupy the pentagonal holes formed by the molybdenum nitride polyhedral rings. Electrical and magnetic characterization of Ni2Mo3N indicate that it is a metallic conductor which antiferromagnetically orders at 14.7 K. Neutron diffraction conducted at 10 K suggests that the size of the magnetic unit cell matches that of the crystallographic unit cell. A version of this nitride phase which is substoichiometric in nitrogen and therefore has a smaller lattice parameter also displays antiferromagnetic ordering, but with a much higher ordering temperature of 68.7 K.