Materials Data on Mg2CoH5 by Materials Project

Abstract

Mg2CoH5 crystallizes in the tetragonal P4/nmm space group. The structure is three-dimensional. there are two inequivalent Mg2+ sites. In the first Mg2+ site, Mg2+ is bonded in a body-centered cubic geometry to eight equivalent H1- atoms. All Mg–H bond lengths are 2.16 Å. In the second Mg2+ site, Mg2+ is bonded to twelve H1- atoms to form distorted MgH12 cuboctahedra that share corners with four equivalent MgH12 cuboctahedra, faces with four equivalent MgH12 cuboctahedra, and faces with four equivalent CoH5 square pyramids. There are four shorter (2.23 Å) and eight longer (2.39 Å) Mg–H bond lengths. Co1+ is bonded to five H1- atoms to form CoH5 square pyramids that share faces with four equivalent MgH12 cuboctahedra. There is four shorter (1.53 Å) and one longer (1.57 Å) Co–H bond length. There are two inequivalent H1- sites. In the first H1- site, H1- is bonded to four equivalent Mg2+ and one Co1+ atom to form a mixture of edge and corner-sharing HMg4Co square pyramids. In the second H1- site, H1- is bonded in a 5-coordinate geometry to four Mg2+ and one Co1+ atom.