Ca(NiS2)2 crystallizes in the triclinic P-1 space group. There are two inequivalent Ca sites. In the first Ca site, Ca(1) is bonded to two equivalent S(1), two equivalent S(2), and two equivalent S(4) atoms to form CaS6 octahedra that share corners with six equivalent Ni(4)S6 octahedra, edges with two equivalent Ca(2)S6 octahedra, edges with two equivalent Ni(1)S6 octahedra, edges with two equivalent Ni(2)S6 octahedra, and edges with two equivalent Ni(3)S6 octahedra. The corner-sharing octahedral tilt angles range from 9-17°. In the second Ca site, Ca(2) is bonded to two equivalent S(2), two equivalent S(3), and two equivalent S(4) atoms to form CaS6 octahedra that share corners with six equivalent Ni(2)S6 octahedra, edges with two equivalent Ca(1)S6 octahedra, edges with two equivalent Ni(1)S6 octahedra, edges with two equivalent Ni(3)S6 octahedra, and edges with two equivalent Ni(4)S6 octahedra. The corner-sharing octahedral tilt angles range from 6-16°. There are four inequivalent Ni sites. In the first Ni site, Ni(1) is bonded to two equivalent S(1), two equivalent S(2), and two equivalent S(3) atoms to form NiS6 octahedra that share edges with two equivalent Ca(1)S6 octahedra, edges with two equivalent Ca(2)S6 octahedra, edges with two equivalent Ni(2)S6 octahedra, edges with two equivalent Ni(3)S6 octahedra, and edges with two equivalent Ni(4)S6 octahedra. In the second Ni site, Ni(2) is bonded to two equivalent S(2), two equivalent S(3), and two equivalent S(4) atoms to form distorted NiS6 octahedra that share corners with six equivalent Ca(2)S6 octahedra, edges with two equivalent Ca(1)S6 octahedra, edges with two equivalent Ni(1)S6 octahedra, edges with two equivalent Ni(3)S6 octahedra, and edges with two equivalent Ni(4)S6 octahedra. The corner-sharing octahedral tilt angles range from 6-16°. In the third Ni site, Ni(3) is bonded to two equivalent S(1), two equivalent S(3), and two equivalent S(4) atoms to form NiS6 octahedra that share edges with two equivalent Ca(1)S6 octahedra, edges with two equivalent Ca(2)S6 octahedra, edges with two equivalent Ni(1)S6 octahedra, edges with two equivalent Ni(2)S6 octahedra, and edges with two equivalent Ni(4)S6 octahedra. In the fourth Ni site, Ni(4) is bonded to two equivalent S(1), two equivalent S(2), and two equivalent S(4) atoms to form NiS6 octahedra that share corners with six equivalent Ca(1)S6 octahedra, edges with two equivalent Ca(2)S6 octahedra, edges with two equivalent Ni(1)S6 octahedra, edges with two equivalent Ni(2)S6 octahedra, and edges with two equivalent Ni(3)S6 octahedra. The corner-sharing octahedral tilt angles range from 9-17°. There are four inequivalent S sites. In the first S site, S(1) is bonded in a rectangular see-saw-like geometry to one Ca(1), one Ni(1), one Ni(3), and one Ni(4) atom. In the second S site, S(2) is bonded to one Ca(1), one Ca(2), one Ni(1), one Ni(2), and one Ni(4) atom to form a mixture of corner and edge-sharing SCa2Ni3 square pyramids. In the third S site, S(3) is bonded in a rectangular see-saw-like geometry to one Ca(2), one Ni(1), one Ni(2), and one Ni(3) atom. In the fourth S site, S(4) is bonded to one Ca(1), one Ca(2), one Ni(2), one Ni(3), and one Ni(4) atom to form a mixture of corner and edge-sharing SCa2Ni3 square pyramids.
Ca(NiS2)2 crystallizes in the triclinic P-1 space group. There are two inequivalent Ca sites. In the first Ca site, Ca(1) is bonded to two equivalent S(1), two equivalent S(2), and two equivalent S(4) atoms to form CaS6 octahedra that share corners with six equivalent Ni(4)S6 octahedra, edges with two equivalent Ca(2)S6 octahedra, edges with two equivalent Ni(1)S6 octahedra, edges with two equivalent Ni(2)S6 octahedra, and edges with two equivalent Ni(3)S6 octahedra. The corner-sharing octahedral tilt angles range from 9-17°. Both Ca(1)-S(1) bond lengths are 2.73 Å. Both Ca(1)-S(2) bond lengths are 2.72 Å. Both Ca(1)-S(4) bond lengths are 2.73 Å. In the second Ca site, Ca(2) is bonded to two equivalent S(2), two equivalent S(3), and two equivalent S(4) atoms to form CaS6 octahedra that share corners with six equivalent Ni(2)S6 octahedra, edges with two equivalent Ca(1)S6 octahedra, edges with two equivalent Ni(1)S6 octahedra, edges with two equivalent Ni(3)S6 octahedra, and edges with two equivalent Ni(4)S6 octahedra. The corner-sharing octahedral tilt angles range from 6-16°. Both Ca(2)-S(2) bond lengths are 2.73 Å. Both Ca(2)-S(3) bond lengths are 2.74 Å. Both Ca(2)-S(4) bond lengths are 2.73 Å. There are four inequivalent Ni sites. In the first Ni site, Ni(1) is bonded to two equivalent S(1), two equivalent S(2), and two equivalent S(3) atoms to form NiS6 octahedra that share edges with two equivalent Ca(1)S6 octahedra, edges with two equivalent Ca(2)S6 octahedra, edges with two equivalent Ni(2)S6 octahedra, edges with two equivalent Ni(3)S6 octahedra, and edges with two equivalent Ni(4)S6 octahedra. Both Ni(1)-S(1) bond lengths are 2.34 Å. Both Ni(1)-S(2) bond lengths are 2.33 Å. Both Ni(1)-S(3) bond lengths are 2.37 Å. In the second Ni site, Ni(2) is bonded to two equivalent S(2), two equivalent S(3), and two equivalent S(4) atoms to form distorted NiS6 octahedra that share corners with six equivalent Ca(2)S6 octahedra, edges with two equivalent Ca(1)S6 octahedra, edges with two equivalent Ni(1)S6 octahedra, edges with two equivalent Ni(3)S6 octahedra, and edges with two equivalent Ni(4)S6 octahedra. The corner-sharing octahedral tilt angles range from 6-16°. Both Ni(2)-S(2) bond lengths are 2.50 Å. Both Ni(2)-S(3) bond lengths are 2.31 Å. Both Ni(2)-S(4) bond lengths are 2.36 Å. In the third Ni site, Ni(3) is bonded to two equivalent S(1), two equivalent S(3), and two equivalent S(4) atoms to form NiS6 octahedra that share edges with two equivalent Ca(1)S6 octahedra, edges with two equivalent Ca(2)S6 octahedra, edges with two equivalent Ni(1)S6 octahedra, edges with two equivalent Ni(2)S6 octahedra, and edges with two equivalent Ni(4)S6 octahedra. Both Ni(3)-S(1) bond lengths are 2.31 Å. Both Ni(3)-S(3) bond lengths are 2.31 Å. Both Ni(3)-S(4) bond lengths are 2.51 Å. In the fourth Ni site, Ni(4) is bonded to two equivalent S(1), two equivalent S(2), and two equivalent S(4) atoms to form NiS6 octahedra that share corners with six equivalent Ca(1)S6 octahedra, edges with two equivalent Ca(2)S6 octahedra, edges with two equivalent Ni(1)S6 octahedra, edges with two equivalent Ni(2)S6 octahedra, and edges with two equivalent Ni(3)S6 octahedra. The corner-sharing octahedral tilt angles range from 9-17°. Both Ni(4)-S(1) bond lengths are 2.33 Å. Both Ni(4)-S(2) bond lengths are 2.38 Å. Both Ni(4)-S(4) bond lengths are 2.48 Å. There are four inequivalent S sites. In the first S site, S(1) is bonded in a rectangular see-saw-like geometry to one Ca(1), one Ni(1), one Ni(3), and one Ni(4) atom. In the second S site, S(2) is bonded to one Ca(1), one Ca(2), one Ni(1), one Ni(2), and one Ni(4) atom to form a mixture of corner and edge-sharing SCa2Ni3 square pyramids. In the third S site, S(3) is bonded in a rectangular see-saw-like geometry to one Ca(2), one Ni(1), one Ni(2), and one Ni(3) atom. In the fourth S site, S(4) is bonded to one Ca(1), one Ca(2), one Ni(2), one Ni(3), and one Ni(4) atom to form a mixture of corner and edge-sharing SCa2Ni3 square pyramids.