Sr2NiSi3 is hexagonal omega structure-derived structured and crystallizes in the hexagonal P-6m2 space group. Sr(1) is bonded to three equivalent Ni(1), three equivalent Si(1), three equivalent Si(2), and three equivalent Si(3) atoms to form a mixture of edge and face-sharing SrSi9Ni3 cuboctahedra. Ni(1) is bonded in a 9-coordinate geometry to six equivalent Sr(1) and three equivalent Si(2) atoms. There are three inequivalent Si sites. In the first Si site, Si(1) is bonded in a 9-coordinate geometry to six equivalent Sr(1) and three equivalent Si(3) atoms. In the second Si site, Si(2) is bonded in a 9-coordinate geometry to six equivalent Sr(1) and three equivalent Ni(1) atoms. In the third Si site, Si(3) is bonded in a 9-coordinate geometry to six equivalent Sr(1) and three equivalent Si(1) atoms.
Sr2NiSi3 is hexagonal omega structure-derived structured and crystallizes in the hexagonal P-6m2 space group. Sr(1) is bonded to three equivalent Ni(1), three equivalent Si(1), three equivalent Si(2), and three equivalent Si(3) atoms to form a mixture of edge and face-sharing SrSi9Ni3 cuboctahedra. All Sr(1)-Ni(1) bond lengths are 3.25 Å. All Sr(1)-Si(1) bond lengths are 3.39 Å. All Sr(1)-Si(2) bond lengths are 3.25 Å. All Sr(1)-Si(3) bond lengths are 3.39 Å. Ni(1) is bonded in a 9-coordinate geometry to six equivalent Sr(1) and three equivalent Si(2) atoms. All Ni(1)-Si(2) bond lengths are 2.36 Å. There are three inequivalent Si sites. In the first Si site, Si(1) is bonded in a 9-coordinate geometry to six equivalent Sr(1) and three equivalent Si(3) atoms. All Si(1)-Si(3) bond lengths are 2.36 Å. In the second Si site, Si(2) is bonded in a 9-coordinate geometry to six equivalent Sr(1) and three equivalent Ni(1) atoms. In the third Si site, Si(3) is bonded in a 9-coordinate geometry to six equivalent Sr(1) and three equivalent Si(1) atoms.