The electronic structures of CaNiN as well as its metallic conductivity and magnetism have been studied by using DFT method. The calculated results indicate that, due to the weak interaction between the NiN^2- chains, the band structures of NiN with different dimensions are similar, which also determine the conductivity and magnetism of the compound. Compared with [MX] chains (M=Pt, Pd; X=halogen atom), it shows that the undistortion of the NiN^2- chain is mainly originated from the compertition between the decrease of the orbital energy andthe increase of the paired energy. For the [MX] chains, the latter effect is dominant and hence, the distortion of their chains is observed. It seems that the smaller distortion the compound has,the more favorable its magnetism will be.

Key words: BAND STRUCTURES, CALCIUM COMPOUDS, NICKEL COMPOUNDS, NITROGEN COMPOUNDS, MAGNETISM, ABERRATION, PARAMAGNETISM, CHAIN STRUCTURE, ELECTRONIC STRUCTURE