Ba2CrNbO6 is (Cubic) Perovskite-derived structured and crystallizes in the hexagonal P6_3/mmc space group. There are three inequivalent Ba sites. In the first Ba site, Ba(1) is bonded to three equivalent O(2), three equivalent O(3), and six equivalent O(1) atoms to form distorted BaO12 cuboctahedra that share corners with nine equivalent Ba(1)O12 cuboctahedra, corners with three equivalent Cr(1)O6 octahedra,  a faceface with one Ba(1)O12 cuboctahedra, faces with three equivalent Ba(2)O12 cuboctahedra, faces with three equivalent Ba(3)O12 cuboctahedra, faces with three equivalent Cr(1)O6 octahedra, and faces with four equivalent Nb(1)O6 octahedra. The corner-sharing octahedral tilt angles are 7°. In the second Ba site, Ba(2) is bonded to six equivalent O(1) and six equivalent O(2) atoms to form BaO12 cuboctahedra that share corners with six equivalent Ba(2)O12 cuboctahedra, corners with six equivalent Ba(3)O12 cuboctahedra, faces with six equivalent Ba(1)O12 cuboctahedra, faces with two equivalent Nb(1)O6 octahedra, and faces with six equivalent Cr(1)O6 octahedra. In the third Ba site, Ba(3) is bonded to six equivalent O(1) and six equivalent O(3) atoms to form BaO12 cuboctahedra that share corners with six equivalent Ba(2)O12 cuboctahedra, corners with six equivalent Ba(3)O12 cuboctahedra, faces with six equivalent Ba(1)O12 cuboctahedra, faces with two equivalent Cr(1)O6 octahedra, and faces with six equivalent Nb(1)O6 octahedra. Nb(1) is bonded to three equivalent O(1) and three equivalent O(3) atoms to form NbO6 octahedra that share corners with three equivalent Nb(1)O6 octahedra, corners with three equivalent Cr(1)O6 octahedra,  a faceface with one Ba(2)O12 cuboctahedra, faces with three equivalent Ba(3)O12 cuboctahedra, and faces with four equivalent Ba(1)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 0-1°. Cr(1) is bonded to three equivalent O(1) and three equivalent O(2) atoms to form CrO6 octahedra that share corners with three equivalent Ba(1)O12 cuboctahedra, corners with three equivalent Nb(1)O6 octahedra,  a faceface with one Ba(3)O12 cuboctahedra, faces with three equivalent Ba(1)O12 cuboctahedra, faces with three equivalent Ba(2)O12 cuboctahedra, and  a faceface with one Cr(1)O6 octahedra. The corner-sharing octahedral tilt angles are 1°. There are three inequivalent O sites. In the first O site, O(3) is bonded in a distorted linear geometry to two equivalent Ba(1), two equivalent Ba(3), and two equivalent Nb(1) atoms. In the second O site, O(1) is bonded in a distorted linear geometry to one Ba(2), one Ba(3), two equivalent Ba(1), one Nb(1), and one Cr(1) atom. In the third O site, O(2) is bonded to two equivalent Ba(1), two equivalent Ba(2), and two equivalent Cr(1) atoms to form a mixture of distorted face and corner-sharing OBa4Cr2 octahedra. The corner-sharing octahedral tilt angles range from 7-60°.
Ba2CrNbO6 is (Cubic) Perovskite-derived structured and crystallizes in the hexagonal P6_3/mmc space group. There are three inequivalent Ba sites. In the first Ba site, Ba(1) is bonded to three equivalent O(2), three equivalent O(3), and six equivalent O(1) atoms to form distorted BaO12 cuboctahedra that share corners with nine equivalent Ba(1)O12 cuboctahedra, corners with three equivalent Cr(1)O6 octahedra,  a faceface with one Ba(1)O12 cuboctahedra, faces with three equivalent Ba(2)O12 cuboctahedra, faces with three equivalent Ba(3)O12 cuboctahedra, faces with three equivalent Cr(1)O6 octahedra, and faces with four equivalent Nb(1)O6 octahedra. The corner-sharing octahedral tilt angles are 7°. All Ba(1)-O(2) bond lengths are 2.77 Å. All Ba(1)-O(3) bond lengths are 3.16 Å. All Ba(1)-O(1) bond lengths are 2.91 Å. In the second Ba site, Ba(2) is bonded to six equivalent O(1) and six equivalent O(2) atoms to form BaO12 cuboctahedra that share corners with six equivalent Ba(2)O12 cuboctahedra, corners with six equivalent Ba(3)O12 cuboctahedra, faces with six equivalent Ba(1)O12 cuboctahedra, faces with two equivalent Nb(1)O6 octahedra, and faces with six equivalent Cr(1)O6 octahedra. All Ba(2)-O(1) bond lengths are 2.94 Å. All Ba(2)-O(2) bond lengths are 2.90 Å. In the third Ba site, Ba(3) is bonded to six equivalent O(1) and six equivalent O(3) atoms to form BaO12 cuboctahedra that share corners with six equivalent Ba(2)O12 cuboctahedra, corners with six equivalent Ba(3)O12 cuboctahedra, faces with six equivalent Ba(1)O12 cuboctahedra, faces with two equivalent Cr(1)O6 octahedra, and faces with six equivalent Nb(1)O6 octahedra. All Ba(3)-O(1) bond lengths are 2.86 Å. All Ba(3)-O(3) bond lengths are 2.89 Å. Nb(1) is bonded to three equivalent O(1) and three equivalent O(3) atoms to form NbO6 octahedra that share corners with three equivalent Nb(1)O6 octahedra, corners with three equivalent Cr(1)O6 octahedra,  a faceface with one Ba(2)O12 cuboctahedra, faces with three equivalent Ba(3)O12 cuboctahedra, and faces with four equivalent Ba(1)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 0-1°. All Nb(1)-O(1) bond lengths are 1.97 Å. All Nb(1)-O(3) bond lengths are 2.07 Å. Cr(1) is bonded to three equivalent O(1) and three equivalent O(2) atoms to form CrO6 octahedra that share corners with three equivalent Ba(1)O12 cuboctahedra, corners with three equivalent Nb(1)O6 octahedra,  a faceface with one Ba(3)O12 cuboctahedra, faces with three equivalent Ba(1)O12 cuboctahedra, faces with three equivalent Ba(2)O12 cuboctahedra, and  a faceface with one Cr(1)O6 octahedra. The corner-sharing octahedral tilt angles are 1°. All Cr(1)-O(1) bond lengths are 2.04 Å. All Cr(1)-O(2) bond lengths are 1.97 Å. There are three inequivalent O sites. In the first O site, O(3) is bonded in a distorted linear geometry to two equivalent Ba(1), two equivalent Ba(3), and two equivalent Nb(1) atoms. In the second O site, O(1) is bonded in a distorted linear geometry to one Ba(2), one Ba(3), two equivalent Ba(1), one Nb(1), and one Cr(1) atom. In the third O site, O(2) is bonded to two equivalent Ba(1), two equivalent Ba(2), and two equivalent Cr(1) atoms to form a mixture of distorted face and corner-sharing OBa4Cr2 octahedra. The corner-sharing octahedral tilt angles range from 7-60°.