RuNiS4 is Pyrite-derived structured and crystallizes in the monoclinic P2_1/c space group. Ru(1) is bonded to two equivalent S(2) and four equivalent S(1) atoms to form RuS6 octahedra that share corners with four equivalent Ru(1)S6 octahedra, corners with eight equivalent Ni(1)S6 octahedra, corners with two equivalent S(2)Ni2RuS tetrahedra, and corners with four equivalent S(1)NiRu2S tetrahedra. The corner-sharing octahedral tilt angles range from 65-66°. Ni(1) is bonded to two equivalent S(1) and four equivalent S(2) atoms to form NiS6 octahedra that share corners with four equivalent Ni(1)S6 octahedra, corners with eight equivalent Ru(1)S6 octahedra, corners with two equivalent S(1)NiRu2S tetrahedra, and corners with four equivalent S(2)Ni2RuS tetrahedra. The corner-sharing octahedral tilt angles range from 65-66°. There are two inequivalent S sites. In the first S site, S(1) is bonded to two equivalent Ru(1), one Ni(1), and one S(1) atom to form distorted SNiRu2S tetrahedra that share  a cornercorner with one Ni(1)S6 octahedra, corners with two equivalent Ru(1)S6 octahedra, corners with seven equivalent S(1)NiRu2S tetrahedra, and corners with eight equivalent S(2)Ni2RuS tetrahedra. The corner-sharing octahedral tilt angles range from 76-77°. In the second S site, S(2) is bonded to one Ru(1), two equivalent Ni(1), and one S(2) atom to form distorted SNi2RuS tetrahedra that share  a cornercorner with one Ru(1)S6 octahedra, corners with two equivalent Ni(1)S6 octahedra, corners with seven equivalent S(2)Ni2RuS tetrahedra, and corners with eight equivalent S(1)NiRu2S tetrahedra. The corner-sharing octahedral tilt angles range from 74-77°.
RuNiS4 is Pyrite-derived structured and crystallizes in the monoclinic P2_1/c space group. Ru(1) is bonded to two equivalent S(2) and four equivalent S(1) atoms to form RuS6 octahedra that share corners with four equivalent Ru(1)S6 octahedra, corners with eight equivalent Ni(1)S6 octahedra, corners with two equivalent S(2)Ni2RuS tetrahedra, and corners with four equivalent S(1)NiRu2S tetrahedra. The corner-sharing octahedral tilt angles range from 65-66°. Both Ru(1)-S(2) bond lengths are 2.36 Å. All Ru(1)-S(1) bond lengths are 2.37 Å. Ni(1) is bonded to two equivalent S(1) and four equivalent S(2) atoms to form NiS6 octahedra that share corners with four equivalent Ni(1)S6 octahedra, corners with eight equivalent Ru(1)S6 octahedra, corners with two equivalent S(1)NiRu2S tetrahedra, and corners with four equivalent S(2)Ni2RuS tetrahedra. The corner-sharing octahedral tilt angles range from 65-66°. Both Ni(1)-S(1) bond lengths are 2.35 Å. There are two shorter (2.36 Å) and two longer (2.41 Å) Ni(1)-S(2) bond lengths. There are two inequivalent S sites. In the first S site, S(1) is bonded to two equivalent Ru(1), one Ni(1), and one S(1) atom to form distorted SNiRu2S tetrahedra that share  a cornercorner with one Ni(1)S6 octahedra, corners with two equivalent Ru(1)S6 octahedra, corners with seven equivalent S(1)NiRu2S tetrahedra, and corners with eight equivalent S(2)Ni2RuS tetrahedra. The corner-sharing octahedral tilt angles range from 76-77°. The S(1)-S(1) bond length is 2.18 Å. In the second S site, S(2) is bonded to one Ru(1), two equivalent Ni(1), and one S(2) atom to form distorted SNi2RuS tetrahedra that share  a cornercorner with one Ru(1)S6 octahedra, corners with two equivalent Ni(1)S6 octahedra, corners with seven equivalent S(2)Ni2RuS tetrahedra, and corners with eight equivalent S(1)NiRu2S tetrahedra. The corner-sharing octahedral tilt angles range from 74-77°. The S(2)-S(2) bond length is 2.09 Å.