Ba2OsNiO6 is (Cubic) Perovskite-derived structured and crystallizes in the monoclinic Cm space group. There are six inequivalent Ba sites. In the first Ba site, Ba(1) is bonded to one O(10), one O(6), two equivalent O(2), two equivalent O(5), two equivalent O(9), and four equivalent O(1) atoms to form BaO12 cuboctahedra that share corners with three equivalent Ba(4)O12 cuboctahedra, corners with three equivalent Ba(6)O12 cuboctahedra, corners with six equivalent Ba(1)O12 cuboctahedra, faces with three equivalent Ba(3)O12 cuboctahedra, faces with three equivalent Ba(5)O12 cuboctahedra,  a faceface with one Os(1)O6 octahedra,  a faceface with one Ni(1)O6 octahedra, faces with three equivalent Os(3)O6 octahedra, and faces with three equivalent Ni(3)O6 octahedra. In the second Ba site, Ba(2) is bonded to one O(12), one O(8), two equivalent O(11), two equivalent O(4), two equivalent O(7), and four equivalent O(3) atoms to form BaO12 cuboctahedra that share corners with three equivalent Ba(3)O12 cuboctahedra, corners with three equivalent Ba(5)O12 cuboctahedra, corners with six equivalent Ba(2)O12 cuboctahedra, faces with three equivalent Ba(4)O12 cuboctahedra, faces with three equivalent Ba(6)O12 cuboctahedra,  a faceface with one Os(1)O6 octahedra,  a faceface with one Ni(1)O6 octahedra, faces with three equivalent Os(2)O6 octahedra, and faces with three equivalent Ni(2)O6 octahedra. In the third Ba site, Ba(3) is bonded to one O(2), one O(8), two equivalent O(1), two equivalent O(6), two equivalent O(7), and four equivalent O(5) atoms to form BaO12 cuboctahedra that share corners with three equivalent Ba(2)O12 cuboctahedra, corners with six equivalent Ba(3)O12 cuboctahedra, corners with three equivalent Ni(3)O6 octahedra,  a faceface with one Ba(5)O12 cuboctahedra, faces with three equivalent Ba(1)O12 cuboctahedra, faces with three equivalent Ba(4)O12 cuboctahedra,  a faceface with one Os(2)O6 octahedra, faces with three equivalent Os(3)O6 octahedra, and faces with three equivalent Ni(1)O6 octahedra. The corner-sharing octahedral tilt angles are 7°. In the fourth Ba site, Ba(4) is bonded to one O(4), one O(6), two equivalent O(3), two equivalent O(5), two equivalent O(8), and four equivalent O(7) atoms to form BaO12 cuboctahedra that share corners with three equivalent Ba(1)O12 cuboctahedra, corners with six equivalent Ba(4)O12 cuboctahedra, corners with three equivalent Ni(2)O6 octahedra,  a faceface with one Ba(6)O12 cuboctahedra, faces with three equivalent Ba(2)O12 cuboctahedra, faces with three equivalent Ba(3)O12 cuboctahedra,  a faceface with one Os(3)O6 octahedra, faces with three equivalent Os(2)O6 octahedra, and faces with three equivalent Ni(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 6-7°. In the fifth Ba site, Ba(5) is bonded to one O(12), one O(2), two equivalent O(1), two equivalent O(10), two equivalent O(11), and four equivalent O(9) atoms to form BaO12 cuboctahedra that share corners with three equivalent Ba(2)O12 cuboctahedra, corners with six equivalent Ba(5)O12 cuboctahedra, corners with three equivalent Os(3)O6 octahedra,  a faceface with one Ba(3)O12 cuboctahedra, faces with three equivalent Ba(1)O12 cuboctahedra, faces with three equivalent Ba(6)O12 cuboctahedra,  a faceface with one Ni(2)O6 octahedra, faces with three equivalent Os(1)O6 octahedra, and faces with three equivalent Ni(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 12-13°. In the sixth Ba site, Ba(6) is bonded to one O(10), one O(4), two equivalent O(12), two equivalent O(3), two equivalent O(9), and four equivalent O(11) atoms to form BaO12 cuboctahedra that share corners with three equivalent Ba(1)O12 cuboctahedra, corners with six equivalent Ba(6)O12 cuboctahedra, corners with three equivalent Os(2)O6 octahedra,  a faceface with one Ba(4)O12 cuboctahedra, faces with three equivalent Ba(2)O12 cuboctahedra, faces with three equivalent Ba(5)O12 cuboctahedra,  a faceface with one Ni(3)O6 octahedra, faces with three equivalent Os(1)O6 octahedra, and faces with three equivalent Ni(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 12-13°. There are three inequivalent Os sites. In the first Os site, Os(1) is bonded to one O(10), one O(12), two equivalent O(11), and two equivalent O(9) atoms to form OsO6 octahedra that share corners with three equivalent Ni(2)O6 octahedra, corners with three equivalent Ni(3)O6 octahedra,  a faceface with one Ba(1)O12 cuboctahedra,  a faceface with one Ba(2)O12 cuboctahedra, faces with three equivalent Ba(5)O12 cuboctahedra, and faces with three equivalent Ba(6)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 4-5°. In the second Os site, Os(2) is bonded to one O(4), one O(8), two equivalent O(3), and two equivalent O(7) atoms to form OsO6 octahedra that share corners with three equivalent Ba(6)O12 cuboctahedra, corners with three equivalent Ni(1)O6 octahedra,  a faceface with one Ba(3)O12 cuboctahedra, faces with three equivalent Ba(2)O12 cuboctahedra, faces with three equivalent Ba(4)O12 cuboctahedra, and  a faceface with one Ni(2)O6 octahedra. The corner-sharing octahedral tilt angles are 1°. In the third Os site, Os(3) is bonded to one O(2), one O(6), two equivalent O(1), and two equivalent O(5) atoms to form OsO6 octahedra that share corners with three equivalent Ba(5)O12 cuboctahedra, corners with three equivalent Ni(1)O6 octahedra,  a faceface with one Ba(4)O12 cuboctahedra, faces with three equivalent Ba(1)O12 cuboctahedra, faces with three equivalent Ba(3)O12 cuboctahedra, and  a faceface with one Ni(3)O6 octahedra. The corner-sharing octahedral tilt angles are 1°. There are three inequivalent Ni sites. In the first Ni site, Ni(1) is bonded to one O(6), one O(8), two equivalent O(5), and two equivalent O(7) atoms to form NiO6 octahedra that share corners with three equivalent Os(2)O6 octahedra, corners with three equivalent Os(3)O6 octahedra,  a faceface with one Ba(1)O12 cuboctahedra,  a faceface with one Ba(2)O12 cuboctahedra, faces with three equivalent Ba(3)O12 cuboctahedra, and faces with three equivalent Ba(4)O12 cuboctahedra. The corner-sharing octahedral tilt angles are 1°. In the second Ni site, Ni(2) is bonded to one O(12), one O(4), two equivalent O(11), and two equivalent O(3) atoms to form NiO6 octahedra that share corners with three equivalent Ba(4)O12 cuboctahedra, corners with three equivalent Os(1)O6 octahedra,  a faceface with one Ba(5)O12 cuboctahedra, faces with three equivalent Ba(2)O12 cuboctahedra, faces with three equivalent Ba(6)O12 cuboctahedra, and  a faceface with one Os(2)O6 octahedra. The corner-sharing octahedral tilt angles are 4°. In the third Ni site, Ni(3) is bonded to one O(10), one O(2), two equivalent O(1), and two equivalent O(9) atoms to form NiO6 octahedra that share corners with three equivalent Ba(3)O12 cuboctahedra, corners with three equivalent Os(1)O6 octahedra,  a faceface with one Ba(6)O12 cuboctahedra, faces with three equivalent Ba(1)O12 cuboctahedra, faces with three equivalent Ba(5)O12 cuboctahedra, and  a faceface with one Os(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 4-5°. There are twelve inequivalent O sites. In the first O site, O(1) is bonded to one Ba(3), one Ba(5), two equivalent Ba(1), one Os(3), and one Ni(3) atom to form a mixture of distorted corner and face-sharing OBa4NiOs octahedra. The corner-sharing octahedral tilt angles range from 6-60°. In the second O site, O(2) is bonded to one Ba(3), one Ba(5), two equivalent Ba(1), one Os(3), and one Ni(3) atom to form a mixture of distorted corner and face-sharing OBa4NiOs octahedra. The corner-sharing octahedral tilt angles range from 6-60°. In the third O site, O(3) is bonded to one Ba(4), one Ba(6), two equivalent Ba(2), one Os(2), and one Ni(2) atom to form a mixture of distorted corner and face-sharing OBa4NiOs octahedra. The corner-sharing octahedral tilt angles range from 6-60°. In the fourth O site, O(4) is bonded to one Ba(4), one Ba(6), two equivalent Ba(2), one Os(2), and one Ni(2) atom to form a mixture of distorted corner and face-sharing OBa4NiOs octahedra. The corner-sharing octahedral tilt angles range from 6-60°. In the fifth O site, O(5) is bonded in a distorted linear geometry to one Ba(1), one Ba(4), two equivalent Ba(3), one Os(3), and one Ni(1) atom. In the sixth O site, O(6) is bonded in a distorted linear geometry to one Ba(1), one Ba(4), two equivalent Ba(3), one Os(3), and one Ni(1) atom. In the seventh O site, O(7) is bonded in a distorted linear geometry to one Ba(2), one Ba(3), two equivalent Ba(4), one Os(2), and one Ni(1) atom. In the eighth O site, O(8) is bonded in a distorted linear geometry to one Ba(2), one Ba(3), two equivalent Ba(4), one Os(2), and one Ni(1) atom. In the ninth O site, O(9) is bonded in a distorted linear geometry to one Ba(1), one Ba(6), two equivalent Ba(5), one Os(1), and one Ni(3) atom. In the tenth O site, O(10) is bonded in a distorted linear geometry to one Ba(1), one Ba(6), two equivalent Ba(5), one Os(1), and one Ni(3) atom. In the eleventh O site, O(11) is bonded in a distorted linear geometry to one Ba(2), one Ba(5), two equivalent Ba(6), one Os(1), and one Ni(2) atom. In the twelfth O site, O(12) is bonded in a distorted linear geometry to one Ba(2), one Ba(5), two equivalent Ba(6), one Os(1), and one Ni(2) atom.
Ba2OsNiO6 is (Cubic) Perovskite-derived structured and crystallizes in the monoclinic Cm space group. There are six inequivalent Ba sites. In the first Ba site, Ba(1) is bonded to one O(10), one O(6), two equivalent O(2), two equivalent O(5), two equivalent O(9), and four equivalent O(1) atoms to form BaO12 cuboctahedra that share corners with three equivalent Ba(4)O12 cuboctahedra, corners with three equivalent Ba(6)O12 cuboctahedra, corners with six equivalent Ba(1)O12 cuboctahedra, faces with three equivalent Ba(3)O12 cuboctahedra, faces with three equivalent Ba(5)O12 cuboctahedra,  a faceface with one Os(1)O6 octahedra,  a faceface with one Ni(1)O6 octahedra, faces with three equivalent Os(3)O6 octahedra, and faces with three equivalent Ni(3)O6 octahedra. The Ba(1)-O(10) bond length is 2.92 Å. The Ba(1)-O(6) bond length is 2.93 Å. Both Ba(1)-O(2) bond lengths are 2.91 Å. Both Ba(1)-O(5) bond lengths are 2.94 Å. Both Ba(1)-O(9) bond lengths are 2.94 Å. There are two shorter (2.91 Å) and two longer (2.92 Å) Ba(1)-O(1) bond lengths. In the second Ba site, Ba(2) is bonded to one O(12), one O(8), two equivalent O(11), two equivalent O(4), two equivalent O(7), and four equivalent O(3) atoms to form BaO12 cuboctahedra that share corners with three equivalent Ba(3)O12 cuboctahedra, corners with three equivalent Ba(5)O12 cuboctahedra, corners with six equivalent Ba(2)O12 cuboctahedra, faces with three equivalent Ba(4)O12 cuboctahedra, faces with three equivalent Ba(6)O12 cuboctahedra,  a faceface with one Os(1)O6 octahedra,  a faceface with one Ni(1)O6 octahedra, faces with three equivalent Os(2)O6 octahedra, and faces with three equivalent Ni(2)O6 octahedra. The Ba(2)-O(12) bond length is 2.94 Å. The Ba(2)-O(8) bond length is 2.93 Å. Both Ba(2)-O(11) bond lengths are 2.94 Å. Both Ba(2)-O(4) bond lengths are 2.91 Å. Both Ba(2)-O(7) bond lengths are 2.94 Å. All Ba(2)-O(3) bond lengths are 2.91 Å. In the third Ba site, Ba(3) is bonded to one O(2), one O(8), two equivalent O(1), two equivalent O(6), two equivalent O(7), and four equivalent O(5) atoms to form BaO12 cuboctahedra that share corners with three equivalent Ba(2)O12 cuboctahedra, corners with six equivalent Ba(3)O12 cuboctahedra, corners with three equivalent Ni(3)O6 octahedra,  a faceface with one Ba(5)O12 cuboctahedra, faces with three equivalent Ba(1)O12 cuboctahedra, faces with three equivalent Ba(4)O12 cuboctahedra,  a faceface with one Os(2)O6 octahedra, faces with three equivalent Os(3)O6 octahedra, and faces with three equivalent Ni(1)O6 octahedra. The corner-sharing octahedral tilt angles are 7°. The Ba(3)-O(2) bond length is 2.85 Å. The Ba(3)-O(8) bond length is 2.96 Å. Both Ba(3)-O(1) bond lengths are 2.87 Å. Both Ba(3)-O(6) bond lengths are 2.90 Å. Both Ba(3)-O(7) bond lengths are 2.96 Å. All Ba(3)-O(5) bond lengths are 2.91 Å. In the fourth Ba site, Ba(4) is bonded to one O(4), one O(6), two equivalent O(3), two equivalent O(5), two equivalent O(8), and four equivalent O(7) atoms to form BaO12 cuboctahedra that share corners with three equivalent Ba(1)O12 cuboctahedra, corners with six equivalent Ba(4)O12 cuboctahedra, corners with three equivalent Ni(2)O6 octahedra,  a faceface with one Ba(6)O12 cuboctahedra, faces with three equivalent Ba(2)O12 cuboctahedra, faces with three equivalent Ba(3)O12 cuboctahedra,  a faceface with one Os(3)O6 octahedra, faces with three equivalent Os(2)O6 octahedra, and faces with three equivalent Ni(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 6-7°. The Ba(4)-O(4) bond length is 2.86 Å. The Ba(4)-O(6) bond length is 2.96 Å. Both Ba(4)-O(3) bond lengths are 2.87 Å. Both Ba(4)-O(5) bond lengths are 2.96 Å. Both Ba(4)-O(8) bond lengths are 2.90 Å. All Ba(4)-O(7) bond lengths are 2.91 Å. In the fifth Ba site, Ba(5) is bonded to one O(12), one O(2), two equivalent O(1), two equivalent O(10), two equivalent O(11), and four equivalent O(9) atoms to form BaO12 cuboctahedra that share corners with three equivalent Ba(2)O12 cuboctahedra, corners with six equivalent Ba(5)O12 cuboctahedra, corners with three equivalent Os(3)O6 octahedra,  a faceface with one Ba(3)O12 cuboctahedra, faces with three equivalent Ba(1)O12 cuboctahedra, faces with three equivalent Ba(6)O12 cuboctahedra,  a faceface with one Ni(2)O6 octahedra, faces with three equivalent Os(1)O6 octahedra, and faces with three equivalent Ni(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 12-13°. The Ba(5)-O(12) bond length is 3.05 Å. The Ba(5)-O(2) bond length is 2.90 Å. Both Ba(5)-O(1) bond lengths are 2.90 Å. Both Ba(5)-O(10) bond lengths are 2.92 Å. Both Ba(5)-O(11) bond lengths are 3.04 Å. There are two shorter (2.92 Å) and two longer (2.93 Å) Ba(5)-O(9) bond lengths. In the sixth Ba site, Ba(6) is bonded to one O(10), one O(4), two equivalent O(12), two equivalent O(3), two equivalent O(9), and four equivalent O(11) atoms to form BaO12 cuboctahedra that share corners with three equivalent Ba(1)O12 cuboctahedra, corners with six equivalent Ba(6)O12 cuboctahedra, corners with three equivalent Os(2)O6 octahedra,  a faceface with one Ba(4)O12 cuboctahedra, faces with three equivalent Ba(2)O12 cuboctahedra, faces with three equivalent Ba(5)O12 cuboctahedra,  a faceface with one Ni(3)O6 octahedra, faces with three equivalent Os(1)O6 octahedra, and faces with three equivalent Ni(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 12-13°. The Ba(6)-O(10) bond length is 3.06 Å. The Ba(6)-O(4) bond length is 2.91 Å. Both Ba(6)-O(12) bond lengths are 2.92 Å. Both Ba(6)-O(3) bond lengths are 2.90 Å. Both Ba(6)-O(9) bond lengths are 3.04 Å. There are two shorter (2.92 Å) and two longer (2.93 Å) Ba(6)-O(11) bond lengths. There are three inequivalent Os sites. In the first Os site, Os(1) is bonded to one O(10), one O(12), two equivalent O(11), and two equivalent O(9) atoms to form OsO6 octahedra that share corners with three equivalent Ni(2)O6 octahedra, corners with three equivalent Ni(3)O6 octahedra,  a faceface with one Ba(1)O12 cuboctahedra,  a faceface with one Ba(2)O12 cuboctahedra, faces with three equivalent Ba(5)O12 cuboctahedra, and faces with three equivalent Ba(6)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 4-5°. The Os(1)-O(10) bond length is 1.95 Å. The Os(1)-O(12) bond length is 1.95 Å. Both Os(1)-O(11) bond lengths are 1.95 Å. Both Os(1)-O(9) bond lengths are 1.95 Å. In the second Os site, Os(2) is bonded to one O(4), one O(8), two equivalent O(3), and two equivalent O(7) atoms to form OsO6 octahedra that share corners with three equivalent Ba(6)O12 cuboctahedra, corners with three equivalent Ni(1)O6 octahedra,  a faceface with one Ba(3)O12 cuboctahedra, faces with three equivalent Ba(2)O12 cuboctahedra, faces with three equivalent Ba(4)O12 cuboctahedra, and  a faceface with one Ni(2)O6 octahedra. The corner-sharing octahedral tilt angles are 1°. The Os(2)-O(4) bond length is 1.97 Å. The Os(2)-O(8) bond length is 1.94 Å. Both Os(2)-O(3) bond lengths are 1.97 Å. Both Os(2)-O(7) bond lengths are 1.95 Å. In the third Os site, Os(3) is bonded to one O(2), one O(6), two equivalent O(1), and two equivalent O(5) atoms to form OsO6 octahedra that share corners with three equivalent Ba(5)O12 cuboctahedra, corners with three equivalent Ni(1)O6 octahedra,  a faceface with one Ba(4)O12 cuboctahedra, faces with three equivalent Ba(1)O12 cuboctahedra, faces with three equivalent Ba(3)O12 cuboctahedra, and  a faceface with one Ni(3)O6 octahedra. The corner-sharing octahedral tilt angles are 1°. The Os(3)-O(2) bond length is 1.98 Å. The Os(3)-O(6) bond length is 1.96 Å. Both Os(3)-O(1) bond lengths are 1.96 Å. Both Os(3)-O(5) bond lengths are 1.94 Å. There are three inequivalent Ni sites. In the first Ni site, Ni(1) is bonded to one O(6), one O(8), two equivalent O(5), and two equivalent O(7) atoms to form NiO6 octahedra that share corners with three equivalent Os(2)O6 octahedra, corners with three equivalent Os(3)O6 octahedra,  a faceface with one Ba(1)O12 cuboctahedra,  a faceface with one Ba(2)O12 cuboctahedra, faces with three equivalent Ba(3)O12 cuboctahedra, and faces with three equivalent Ba(4)O12 cuboctahedra. The corner-sharing octahedral tilt angles are 1°. The Ni(1)-O(6) bond length is 2.10 Å. The Ni(1)-O(8) bond length is 2.11 Å. Both Ni(1)-O(5) bond lengths are 2.11 Å. Both Ni(1)-O(7) bond lengths are 2.10 Å. In the second Ni site, Ni(2) is bonded to one O(12), one O(4), two equivalent O(11), and two equivalent O(3) atoms to form NiO6 octahedra that share corners with three equivalent Ba(4)O12 cuboctahedra, corners with three equivalent Os(1)O6 octahedra,  a faceface with one Ba(5)O12 cuboctahedra, faces with three equivalent Ba(2)O12 cuboctahedra, faces with three equivalent Ba(6)O12 cuboctahedra, and  a faceface with one Os(2)O6 octahedra. The corner-sharing octahedral tilt angles are 4°. The Ni(2)-O(12) bond length is 2.04 Å. The Ni(2)-O(4) bond length is 2.13 Å. Both Ni(2)-O(11) bond lengths are 2.04 Å. Both Ni(2)-O(3) bond lengths are 2.13 Å. In the third Ni site, Ni(3) is bonded to one O(10), one O(2), two equivalent O(1), and two equivalent O(9) atoms to form NiO6 octahedra that share corners with three equivalent Ba(3)O12 cuboctahedra, corners with three equivalent Os(1)O6 octahedra,  a faceface with one Ba(6)O12 cuboctahedra, faces with three equivalent Ba(1)O12 cuboctahedra, faces with three equivalent Ba(5)O12 cuboctahedra, and  a faceface with one Os(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 4-5°. The Ni(3)-O(10) bond length is 2.05 Å. The Ni(3)-O(2) bond length is 2.13 Å. Both Ni(3)-O(1) bond lengths are 2.13 Å. Both Ni(3)-O(9) bond lengths are 2.04 Å. There are twelve inequivalent O sites. In the first O site, O(1) is bonded to one Ba(3), one Ba(5), two equivalent Ba(1), one Os(3), and one Ni(3) atom to form a mixture of distorted corner and face-sharing OBa4NiOs octahedra. The corner-sharing octahedral tilt angles range from 6-60°. In the second O site, O(2) is bonded to one Ba(3), one Ba(5), two equivalent Ba(1), one Os(3), and one Ni(3) atom to form a mixture of distorted corner and face-sharing OBa4NiOs octahedra. The corner-sharing octahedral tilt angles range from 6-60°. In the third O site, O(3) is bonded to one Ba(4), one Ba(6), two equivalent Ba(2), one Os(2), and one Ni(2) atom to form a mixture of distorted corner and face-sharing OBa4NiOs octahedra. The corner-sharing octahedral tilt angles range from 6-60°. In the fourth O site, O(4) is bonded to one Ba(4), one Ba(6), two equivalent Ba(2), one Os(2), and one Ni(2) atom to form a mixture of distorted corner and face-sharing OBa4NiOs octahedra. The corner-sharing octahedral tilt angles range from 6-60°. In the fifth O site, O(5) is bonded in a distorted linear geometry to one Ba(1), one Ba(4), two equivalent Ba(3), one Os(3), and one Ni(1) atom. In the sixth O site, O(6) is bonded in a distorted linear geometry to one Ba(1), one Ba(4), two equivalent Ba(3), one Os(3), and one Ni(1) atom. In the seventh O site, O(7) is bonded in a distorted linear geometry to one Ba(2), one Ba(3), two equivalent Ba(4), one Os(2), and one Ni(1) atom. In the eighth O site, O(8) is bonded in a distorted linear geometry to one Ba(2), one Ba(3), two equivalent Ba(4), one Os(2), and one Ni(1) atom. In the ninth O site, O(9) is bonded in a distorted linear geometry to one Ba(1), one Ba(6), two equivalent Ba(5), one Os(1), and one Ni(3) atom. In the tenth O site, O(10) is bonded in a distorted linear geometry to one Ba(1), one Ba(6), two equivalent Ba(5), one Os(1), and one Ni(3) atom. In the eleventh O site, O(11) is bonded in a distorted linear geometry to one Ba(2), one Ba(5), two equivalent Ba(6), one Os(1), and one Ni(2) atom. In the twelfth O site, O(12) is bonded in a distorted linear geometry to one Ba(2), one Ba(5), two equivalent Ba(6), one Os(1), and one Ni(2) atom.