Ca7SnN6 crystallizes in the orthorhombic Ibam space group. There are three inequivalent Ca sites. In the first Ca site, Ca(1) is bonded to two equivalent N(1) and two equivalent N(2) atoms to form CaN4 trigonal pyramids that share corners with two equivalent Sn(1)N4 tetrahedra and  an edgeedge with one Ca(1)N4 trigonal pyramid. In the second Ca site, Ca(2) is bonded in a 5-coordinate geometry to two equivalent N(2) and three equivalent N(1) atoms. In the third Ca site, Ca(3) is bonded in a 4-coordinate geometry to four equivalent N(1) atoms. Sn(1) is bonded to four equivalent N(1) atoms to form distorted SnN4 tetrahedra that share corners with four equivalent Ca(1)N4 trigonal pyramids. There are two inequivalent N sites. In the first N site, N(1) is bonded to one Ca(1), one Ca(3), three equivalent Ca(2), and one Sn(1) atom to form a mixture of distorted edge, corner, and face-sharing NCa5Sn octahedra. The corner-sharing octahedral tilt angles range from 41-65°. In the second N site, N(2) is bonded in a 6-coordinate geometry to two equivalent Ca(1) and four equivalent Ca(2) atoms.
Ca7SnN6 crystallizes in the orthorhombic Ibam space group. There are three inequivalent Ca sites. In the first Ca site, Ca(1) is bonded to two equivalent N(1) and two equivalent N(2) atoms to form CaN4 trigonal pyramids that share corners with two equivalent Sn(1)N4 tetrahedra and  an edgeedge with one Ca(1)N4 trigonal pyramid. Both Ca(1)-N(1) bond lengths are 2.45 Å. There is one shorter (2.44 Å) and one longer (2.48 Å) Ca(1)-N(2) bond length. In the second Ca site, Ca(2) is bonded in a 5-coordinate geometry to two equivalent N(2) and three equivalent N(1) atoms. There is one shorter (2.45 Å) and one longer (2.70 Å) Ca(2)-N(2) bond length. There are a spread of Ca(2)-N(1) bond distances ranging from 2.32-2.87 Å. In the third Ca site, Ca(3) is bonded in a 4-coordinate geometry to four equivalent N(1) atoms. All Ca(3)-N(1) bond lengths are 2.51 Å. Sn(1) is bonded to four equivalent N(1) atoms to form distorted SnN4 tetrahedra that share corners with four equivalent Ca(1)N4 trigonal pyramids. All Sn(1)-N(1) bond lengths are 2.10 Å. There are two inequivalent N sites. In the first N site, N(1) is bonded to one Ca(1), one Ca(3), three equivalent Ca(2), and one Sn(1) atom to form a mixture of distorted edge, corner, and face-sharing NCa5Sn octahedra. The corner-sharing octahedral tilt angles range from 41-65°. In the second N site, N(2) is bonded in a 6-coordinate geometry to two equivalent Ca(1) and four equivalent Ca(2) atoms.