Ca7ZrN6 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 tetrahedra that share corners with two equivalent Zr(1)N4 tetrahedra and  an edgeedge with one Ca(1)N4 tetrahedra. In the second Ca site, Ca(2) is bonded in a 4-coordinate geometry to two equivalent N(1) and two equivalent N(2) atoms. In the third Ca site, Ca(3) is bonded in a 4-coordinate geometry to four equivalent N(1) atoms. Zr(1) is bonded to four equivalent N(1) atoms to form ZrN4 tetrahedra that share corners with four equivalent Ca(1)N4 tetrahedra. There are two inequivalent N sites. In the first N site, N(1) is bonded in a 5-coordinate geometry to one Ca(1), one Ca(3), two equivalent Ca(2), and one Zr(1) atom. 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.
Ca7ZrN6 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 tetrahedra that share corners with two equivalent Zr(1)N4 tetrahedra and  an edgeedge with one Ca(1)N4 tetrahedra. Both Ca(1)-N(1) bond lengths are 2.42 Å. There is one shorter (2.43 Å) and one longer (2.56 Å) Ca(1)-N(2) bond length. In the second Ca site, Ca(2) is bonded in a 4-coordinate geometry to two equivalent N(1) and two equivalent N(2) atoms. There is one shorter (2.36 Å) and one longer (2.53 Å) Ca(2)-N(1) bond length. There is one shorter (2.47 Å) and one longer (2.57 Å) Ca(2)-N(2) bond length. 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 2.52 Å. Zr(1) is bonded to four equivalent N(1) atoms to form ZrN4 tetrahedra that share corners with four equivalent Ca(1)N4 tetrahedra. All Zr(1)-N(1) bond lengths are 2.09 Å. There are two inequivalent N sites. In the first N site, N(1) is bonded in a 5-coordinate geometry to one Ca(1), one Ca(3), two equivalent Ca(2), and one Zr(1) atom. 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.