Materials Data on Na6SiNi2(CO4)4 by Materials Project
Na6Ni2Si(CO4)4 crystallizes in the cubic Fd-3 space group. The structure is three-dimensional. Na1+ is bonded to six O2- atoms to form distorted NaO6 octahedra that share corners with eight equivalent NaO6 octahedra, edges with two equivalent NiO6 octahedra, and an edgeedge with one SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 60–86°. There are a spread of Na–O bond distances ranging from 2.41–2.48 Å. Ni3+ is bonded to six equivalent O2- atoms to form NiO6 octahedra that share edges with six equivalent NaO6 octahedra. All Ni–O bond lengths are 2.09 Å. Si4+ is bonded to four equivalent O2- atoms to form SiO4 tetrahedra that share edges with six equivalent NaO6 octahedra. All Si–O bond lengths are 1.64 Å. C4+ is bonded in a trigonal planar geometry to three equivalent O2- atoms. All C–O bond lengths are 1.30 Å. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded to three equivalent Na1+ and one Si4+ atom to form distorted edge-sharing ONa3Si trigonal pyramids. In the second O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to two equivalent Na1+, one Ni3+, and one C4+ atom.