Materials Data on MgNb3 by Materials Project

Abstract

MgNb3 is alpha bismuth trifluoride structured and crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Mg is bonded to twelve Nb atoms to form distorted MgNb12 cuboctahedra that share corners with four equivalent MgNb12 cuboctahedra, corners with eight equivalent NbMg4Nb8 cuboctahedra, edges with eight equivalent MgNb12 cuboctahedra, faces with four equivalent MgNb12 cuboctahedra, and faces with six equivalent NbMg4Nb8 cuboctahedra. There are eight shorter (2.90 Å) and four longer (3.16 Å) Mg–Nb bond lengths. There are two inequivalent Nb sites. In the first Nb site, Nb is bonded to four equivalent Mg and eight equivalent Nb atoms to form NbMg4Nb8 cuboctahedra that share corners with four equivalent NbMg4Nb8 cuboctahedra, corners with eight equivalent MgNb12 cuboctahedra, edges with eight equivalent NbMg4Nb8 cuboctahedra, faces with four equivalent NbMg4Nb8 cuboctahedra, and faces with six equivalent MgNb12 cuboctahedra. All Nb–Nb bond lengths are 2.90 Å. In the second Nb site, Nb is bonded in a 12-coordinate geometry to four equivalent Mg and four equivalent Nb atoms.