Materials Data on Mg2SiNi3 by Materials Project
Mg2Ni3Si is Frank-Kasper $\mu$ Phase-derived structured and crystallizes in the trigonal R-3m space group. The structure is three-dimensional. Mg is bonded in a 12-coordinate geometry to four equivalent Mg, nine equivalent Ni, and three equivalent Si atoms. There are one shorter (2.76 Å) and three longer (3.03 Å) Mg–Mg bond lengths. There are three shorter (2.71 Å) and six longer (2.86 Å) Mg–Ni bond lengths. All Mg–Si bond lengths are 2.92 Å. Ni is bonded to six equivalent Mg, four equivalent Ni, and two equivalent Si atoms to form NiMg6Si2Ni4 cuboctahedra that share corners with four equivalent SiMg6Ni6 cuboctahedra, corners with fourteen equivalent NiMg6Si2Ni4 cuboctahedra, edges with six equivalent NiMg6Si2Ni4 cuboctahedra, faces with six equivalent SiMg6Ni6 cuboctahedra, and faces with twelve equivalent NiMg6Si2Ni4 cuboctahedra. All Ni–Ni bond lengths are 2.50 Å. Both Ni–Si bond lengths are 2.33 Å. Si is bonded to six equivalent Mg and six equivalent Ni atoms to form SiMg6Ni6 cuboctahedra that share corners with six equivalent SiMg6Ni6 cuboctahedra, corners with twelve equivalent NiMg6Si2Ni4 cuboctahedra, edges with six equivalent SiMg6Ni6 cuboctahedra, and faces with eighteen equivalent NiMg6Si2Ni4 cuboctahedra.