Ca3NbO6 crystallizes in the monoclinic P2_1/c space group. There are two inequivalent Ca sites. In the first Ca site, Ca(1) is bonded in a 8-coordinate geometry to two equivalent O(1), three equivalent O(2), and three equivalent O(3) atoms. In the second Ca site, Ca(2) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form CaO6 octahedra that share corners with six equivalent Nb(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 35-42°. Nb(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form NbO6 octahedra that share corners with six equivalent Ca(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 35-42°. There are three inequivalent O sites. In the first O site, O(1) is bonded to one Ca(2), two equivalent Ca(1), and one Nb(1) atom to form distorted corner-sharing OCa3Nb tetrahedra. In the second O site, O(2) is bonded in a 4-coordinate geometry to one Ca(2), three equivalent Ca(1), and one Nb(1) atom. In the third O site, O(3) is bonded in a 5-coordinate geometry to one Ca(2), three equivalent Ca(1), and one Nb(1) atom.
Ca3NbO6 crystallizes in the monoclinic P2_1/c space group. There are two inequivalent Ca sites. In the first Ca site, Ca(1) is bonded in a 8-coordinate geometry to two equivalent O(1), three equivalent O(2), and three equivalent O(3) atoms. There is one shorter (2.34 Å) and one longer (2.42 Å) Ca(1)-O(1) bond length. There are a spread of Ca(1)-O(2) bond distances ranging from 2.37-3.06 Å. There are a spread of Ca(1)-O(3) bond distances ranging from 2.34-2.82 Å. In the second Ca site, Ca(2) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form CaO6 octahedra that share corners with six equivalent Nb(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 35-42°. Both Ca(2)-O(1) bond lengths are 2.34 Å. Both Ca(2)-O(2) bond lengths are 2.35 Å. Both Ca(2)-O(3) bond lengths are 2.30 Å. Nb(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form NbO6 octahedra that share corners with six equivalent Ca(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 35-42°. Both Nb(1)-O(1) bond lengths are 2.02 Å. Both Nb(1)-O(2) bond lengths are 2.04 Å. Both Nb(1)-O(3) bond lengths are 2.01 Å. There are three inequivalent O sites. In the first O site, O(1) is bonded to one Ca(2), two equivalent Ca(1), and one Nb(1) atom to form distorted corner-sharing OCa3Nb tetrahedra. In the second O site, O(2) is bonded in a 4-coordinate geometry to one Ca(2), three equivalent Ca(1), and one Nb(1) atom. In the third O site, O(3) is bonded in a 5-coordinate geometry to one Ca(2), three equivalent Ca(1), and one Nb(1) atom.