BaNiS2 crystallizes in the tetragonal P4/nmm space group. Ba(1) is bonded to five equivalent S(2) atoms to form a mixture of distorted edge and corner-sharing BaS5 square pyramids. Ni(1) is bonded in a 5-coordinate geometry to one S(2) and four equivalent S(1) atoms. There are two inequivalent S sites. In the first S site, S(1) is bonded in a 4-coordinate geometry to four equivalent Ni(1) atoms. In the second S site, S(2) is bonded to five equivalent Ba(1) and one Ni(1) atom to form a mixture of edge and corner-sharing SBa5Ni octahedra. The corner-sharing octahedral tilt angles are 13°.
BaNiS2 crystallizes in the tetragonal P4/nmm space group. Ba(1) is bonded to five equivalent S(2) atoms to form a mixture of distorted edge and corner-sharing BaS5 square pyramids. There are four shorter (3.15 Å) and one longer (3.19 Å) Ba(1)-S(2) bond length. Ni(1) is bonded in a 5-coordinate geometry to one S(2) and four equivalent S(1) atoms. The Ni(1)-S(2) bond length is 2.31 Å. All Ni(1)-S(1) bond lengths are 2.34 Å. There are two inequivalent S sites. In the first S site, S(1) is bonded in a 4-coordinate geometry to four equivalent Ni(1) atoms. In the second S site, S(2) is bonded to five equivalent Ba(1) and one Ni(1) atom to form a mixture of edge and corner-sharing SBa5Ni octahedra. The corner-sharing octahedral tilt angles are 13°.