Materials Data on KMg3 by Materials Project

Abstract

KMg3 is alpha bismuth trifluoride structured and crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. K is bonded to twelve Mg atoms to form distorted KMg12 cuboctahedra that share corners with four equivalent KMg12 cuboctahedra, corners with eight equivalent MgK4Mg8 cuboctahedra, edges with eight equivalent KMg12 cuboctahedra, faces with four equivalent KMg12 cuboctahedra, and faces with six equivalent MgK4Mg8 cuboctahedra. There are eight shorter (3.40 Å) and four longer (3.75 Å) K–Mg bond lengths. There are two inequivalent Mg sites. In the first Mg site, Mg is bonded to four equivalent K and eight equivalent Mg atoms to form MgK4Mg8 cuboctahedra that share corners with four equivalent MgK4Mg8 cuboctahedra, corners with eight equivalent KMg12 cuboctahedra, edges with eight equivalent MgK4Mg8 cuboctahedra, faces with four equivalent MgK4Mg8 cuboctahedra, and faces with six equivalent KMg12 cuboctahedra. All Mg–Mg bond lengths are 3.40 Å. In the second Mg site, Mg is bonded in a distorted body-centered cubic geometry to four equivalent K and four equivalent Mg atoms.