NixFe3-xN were synthesized with the route starting from NixFe3-xO4 (x = 0, 0.5, 1 and 1.5) powders, to NixFe3-x alloys via reduction in the H-2/N-2 mixture gases and finally to NixFe3-xN through nitriding in NH3 at 1000 degrees C. The structural transitions and the magnetic field and temperature dependent magnetizations were systematically investigated for three systems of NixFe3-xO4, NixFe3-x alloys and NixFe3-xN nitrides. For the NixFe3-xN nitrides, the Ni fraction was expanded to x= 1.5 while it was terminated at x = 0.8 in many previous reports. Several novel magnetic properties were observed: the moments of NixFe3-x alloys with x = 0.5 and 1.5 are 2.15 mu(B)/f.u. and 1.53 mu(B)/f.u., larger than previously reported values and the theoretically calculated ones; Unexpectedly, the gamma'-NiFe2N has the larger magnetization than the corresponding NiFe2 alloy, because, generally, the hybridization of 3d and 2p states in nitrides decreases the magnetic moment of Fe. (C) 2017 Elsevier Ltd. All rights reserved.