Ca3(NbN2)2 crystallizes in the monoclinic C2/c space group. There are two inequivalent Ca sites. In the first Ca site, Ca(1) is bonded in a 3-coordinate geometry to one N(2) and three equivalent N(1) atoms. In the second Ca site, Ca(2) is bonded in a distorted see-saw-like geometry to four equivalent N(2) atoms. Nb(1) is bonded to two equivalent N(1) and two equivalent N(2) atoms to form a mixture of distorted edge and corner-sharing NbN4 tetrahedra. There are two inequivalent N sites. In the first N site, N(1) is bonded in a 5-coordinate geometry to three equivalent Ca(1) and two equivalent Nb(1) atoms. In the second N site, N(2) is bonded to one Ca(1), two equivalent Ca(2), and two equivalent Nb(1) atoms to form a mixture of distorted edge and corner-sharing NCa3Nb2 trigonal bipyramids.
Ca3(NbN2)2 crystallizes in the monoclinic C2/c space group. There are two inequivalent Ca sites. In the first Ca site, Ca(1) is bonded in a 3-coordinate geometry to one N(2) and three equivalent N(1) atoms. The Ca(1)-N(2) bond length is 2.46 Å. There are a spread of Ca(1)-N(1) bond distances ranging from 2.38-3.00 Å. In the second Ca site, Ca(2) is bonded in a distorted see-saw-like geometry to four equivalent N(2) atoms. There are two shorter (2.39 Å) and two longer (2.47 Å) Ca(2)-N(2) bond lengths. Nb(1) is bonded to two equivalent N(1) and two equivalent N(2) atoms to form a mixture of distorted edge and corner-sharing NbN4 tetrahedra. There is one shorter (1.98 Å) and one longer (2.18 Å) Nb(1)-N(1) bond length. Both Nb(1)-N(2) bond lengths are 2.06 Å. There are two inequivalent N sites. In the first N site, N(1) is bonded in a 5-coordinate geometry to three equivalent Ca(1) and two equivalent Nb(1) atoms. In the second N site, N(2) is bonded to one Ca(1), two equivalent Ca(2), and two equivalent Nb(1) atoms to form a mixture of distorted edge and corner-sharing NCa3Nb2 trigonal bipyramids.