CoNiSi4 is half-Heusler-like structured and crystallizes in the trigonal R-3m space group. Co(1) is bonded in a body-centered cubic geometry to two equivalent Si(2) and six equivalent Si(1) atoms. Ni(1) is bonded in a body-centered cubic geometry to two equivalent Si(1) and six equivalent Si(2) atoms. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded to three equivalent Co(1), one Ni(1), three equivalent Si(1), and three equivalent Si(2) atoms to form distorted SiCo3Si6Ni tetrahedra that share corners with four equivalent Si(1)Co3Si6Ni tetrahedra, corners with six equivalent Si(2)CoSi3Ni3 tetrahedra, edges with three equivalent Si(1)Co3Si6Ni tetrahedra, edges with three equivalent Si(2)CoSi3Ni3 tetrahedra, faces with three equivalent Si(2)CoSi3Ni3 tetrahedra, and faces with six equivalent Si(1)Co3Si6Ni tetrahedra. In the second Si site, Si(2) is bonded to one Co(1), three equivalent Ni(1), and three equivalent Si(1) atoms to form distorted SiCoSi3Ni3 tetrahedra that share corners with four equivalent Si(2)CoSi3Ni3 tetrahedra, corners with six equivalent Si(1)Co3Si6Ni tetrahedra, edges with three equivalent Si(1)Co3Si6Ni tetrahedra, edges with nine equivalent Si(2)CoSi3Ni3 tetrahedra, and faces with three equivalent Si(1)Co3Si6Ni tetrahedra.
CoNiSi4 is half-Heusler-like structured and crystallizes in the trigonal R-3m space group. Co(1) is bonded in a body-centered cubic geometry to two equivalent Si(2) and six equivalent Si(1) atoms. Both Co(1)-Si(2) bond lengths are 2.28 Å. All Co(1)-Si(1) bond lengths are 2.30 Å. Ni(1) is bonded in a body-centered cubic geometry to two equivalent Si(1) and six equivalent Si(2) atoms. Both Ni(1)-Si(1) bond lengths are 2.35 Å. All Ni(1)-Si(2) bond lengths are 2.32 Å. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded to three equivalent Co(1), one Ni(1), three equivalent Si(1), and three equivalent Si(2) atoms to form distorted SiCo3Si6Ni tetrahedra that share corners with four equivalent Si(1)Co3Si6Ni tetrahedra, corners with six equivalent Si(2)CoSi3Ni3 tetrahedra, edges with three equivalent Si(1)Co3Si6Ni tetrahedra, edges with three equivalent Si(2)CoSi3Ni3 tetrahedra, faces with three equivalent Si(2)CoSi3Ni3 tetrahedra, and faces with six equivalent Si(1)Co3Si6Ni tetrahedra. All Si(1)-Si(1) bond lengths are 2.62 Å. All Si(1)-Si(2) bond lengths are 2.67 Å. In the second Si site, Si(2) is bonded to one Co(1), three equivalent Ni(1), and three equivalent Si(1) atoms to form distorted SiCoSi3Ni3 tetrahedra that share corners with four equivalent Si(2)CoSi3Ni3 tetrahedra, corners with six equivalent Si(1)Co3Si6Ni tetrahedra, edges with three equivalent Si(1)Co3Si6Ni tetrahedra, edges with nine equivalent Si(2)CoSi3Ni3 tetrahedra, and faces with three equivalent Si(1)Co3Si6Ni tetrahedra.