Na3Ca2BiO6 is Caswellsilverite-derived structured and crystallizes in the orthorhombic Fddd space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded to two equivalent O(2) and four equivalent O(1) atoms to form NaO6 octahedra that share corners with two equivalent Na(1)O6 octahedra, corners with two equivalent Ca(1)O6 octahedra, corners with two equivalent Bi(1)O6 octahedra, edges with two equivalent Na(1)O6 octahedra, edges with two equivalent Bi(1)O6 octahedra, edges with three equivalent Na(2)O6 octahedra, and edges with five equivalent Ca(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 4-12°. In the second Na site, Na(2) is bonded to two equivalent O(2) and four equivalent O(1) atoms to form NaO6 octahedra that share corners with two equivalent Bi(1)O6 octahedra, corners with four equivalent Ca(1)O6 octahedra, edges with two equivalent Bi(1)O6 octahedra, edges with four equivalent Ca(1)O6 octahedra, and edges with six equivalent Na(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 0-11°. Ca(1) is bonded to two equivalent O(2) and four equivalent O(1) atoms to form CaO6 octahedra that share corners with two equivalent Na(1)O6 octahedra, corners with two equivalent Na(2)O6 octahedra, corners with two equivalent Ca(1)O6 octahedra, edges with two equivalent Na(2)O6 octahedra, edges with two equivalent Ca(1)O6 octahedra, edges with three equivalent Bi(1)O6 octahedra, and edges with five equivalent Na(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 10-13°. Bi(1) is bonded to two equivalent O(2) and four equivalent O(1) atoms to form BiO6 octahedra that share corners with two equivalent Na(2)O6 octahedra, corners with four equivalent Na(1)O6 octahedra, edges with two equivalent Na(2)O6 octahedra, edges with four equivalent Na(1)O6 octahedra, and edges with six equivalent Ca(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 0-4°. There are two inequivalent O sites. In the first O site, O(1) is bonded to one Na(2), two equivalent Na(1), two equivalent Ca(1), and one Bi(1) atom to form a mixture of edge and corner-sharing ONa3Ca2Bi octahedra. The corner-sharing octahedral tilt angles range from 2-9°. In the second O site, O(2) is bonded to one Na(2), two equivalent Na(1), two equivalent Ca(1), and one Bi(1) atom to form a mixture of edge and corner-sharing ONa3Ca2Bi octahedra. The corner-sharing octahedral tilt angles range from 0-9°.
Na3Ca2BiO6 is Caswellsilverite-derived structured and crystallizes in the orthorhombic Fddd space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded to two equivalent O(2) and four equivalent O(1) atoms to form NaO6 octahedra that share corners with two equivalent Na(1)O6 octahedra, corners with two equivalent Ca(1)O6 octahedra, corners with two equivalent Bi(1)O6 octahedra, edges with two equivalent Na(1)O6 octahedra, edges with two equivalent Bi(1)O6 octahedra, edges with three equivalent Na(2)O6 octahedra, and edges with five equivalent Ca(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 4-12°. Both Na(1)-O(2) bond lengths are 2.45 Å. There are two shorter (2.50 Å) and two longer (2.55 Å) Na(1)-O(1) bond lengths. In the second Na site, Na(2) is bonded to two equivalent O(2) and four equivalent O(1) atoms to form NaO6 octahedra that share corners with two equivalent Bi(1)O6 octahedra, corners with four equivalent Ca(1)O6 octahedra, edges with two equivalent Bi(1)O6 octahedra, edges with four equivalent Ca(1)O6 octahedra, and edges with six equivalent Na(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 0-11°. Both Na(2)-O(2) bond lengths are 2.70 Å. All Na(2)-O(1) bond lengths are 2.44 Å. Ca(1) is bonded to two equivalent O(2) and four equivalent O(1) atoms to form CaO6 octahedra that share corners with two equivalent Na(1)O6 octahedra, corners with two equivalent Na(2)O6 octahedra, corners with two equivalent Ca(1)O6 octahedra, edges with two equivalent Na(2)O6 octahedra, edges with two equivalent Ca(1)O6 octahedra, edges with three equivalent Bi(1)O6 octahedra, and edges with five equivalent Na(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 10-13°. Both Ca(1)-O(2) bond lengths are 2.37 Å. There are two shorter (2.40 Å) and two longer (2.41 Å) Ca(1)-O(1) bond lengths. Bi(1) is bonded to two equivalent O(2) and four equivalent O(1) atoms to form BiO6 octahedra that share corners with two equivalent Na(2)O6 octahedra, corners with four equivalent Na(1)O6 octahedra, edges with two equivalent Na(2)O6 octahedra, edges with four equivalent Na(1)O6 octahedra, and edges with six equivalent Ca(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 0-4°. Both Bi(1)-O(2) bond lengths are 2.17 Å. All Bi(1)-O(1) bond lengths are 2.19 Å. There are two inequivalent O sites. In the first O site, O(1) is bonded to one Na(2), two equivalent Na(1), two equivalent Ca(1), and one Bi(1) atom to form a mixture of edge and corner-sharing ONa3Ca2Bi octahedra. The corner-sharing octahedral tilt angles range from 2-9°. In the second O site, O(2) is bonded to one Na(2), two equivalent Na(1), two equivalent Ca(1), and one Bi(1) atom to form a mixture of edge and corner-sharing ONa3Ca2Bi octahedra. The corner-sharing octahedral tilt angles range from 0-9°.