Materials Data on SiNi2As by Materials Project
Ni2SiAs crystallizes in the orthorhombic Pbca space group. The structure is three-dimensional. there are two inequivalent Ni+2.50+ sites. In the first Ni+2.50+ site, Ni+2.50+ is bonded in a 5-coordinate geometry to two equivalent Si4- and four equivalent As1- atoms. Both Ni–Si bond lengths are 2.30 Å. There are a spread of Ni–As bond distances ranging from 2.35–3.06 Å. In the second Ni+2.50+ site, Ni+2.50+ is bonded to four equivalent Si4- and two equivalent As1- atoms to form a mixture of distorted corner, edge, and face-sharing NiSi4As2 octahedra. The corner-sharing octahedra tilt angles range from 44–57°. There are a spread of Ni–Si bond distances ranging from 2.32–2.41 Å. Both Ni–As bond lengths are 2.47 Å. Si4- is bonded in a 8-coordinate geometry to six Ni+2.50+, one Si4-, and one As1- atom. The Si–Si bond length is 2.57 Å. The Si–As bond length is 2.68 Å. As1- is bonded in a 7-coordinate geometry to six Ni+2.50+ and one Si4- atom.