Materials Data on TiFeH2 by Materials Project
TiFeH2 crystallizes in the orthorhombic Cmmm space group. The structure is three-dimensional. Ti is bonded to seven H atoms to form distorted TiH7 pentagonal bipyramids that share corners with seven equivalent TiH7 pentagonal bipyramids, edges with three equivalent TiH7 pentagonal bipyramids, edges with eight equivalent FeH5 trigonal bipyramids, and faces with two equivalent TiH7 pentagonal bipyramids. There are a spread of Ti–H bond distances ranging from 1.99–2.09 Å. Fe is bonded to five H atoms to form FeH5 trigonal bipyramids that share corners with seven equivalent FeH5 trigonal bipyramids, edges with eight equivalent TiH7 pentagonal bipyramids, and an edgeedge with one FeH5 trigonal bipyramid. There are a spread of Fe–H bond distances ranging from 1.78–1.88 Å. There are three inequivalent H sites. In the first H site, H is bonded to four equivalent Ti and two equivalent Fe atoms to form a mixture of edge, face, and corner-sharing HTi4Fe2 octahedra. The corner-sharing octahedra tilt angles range from 13–58°. In the second H site, H is bonded to four equivalent Ti and two equivalent Fe atoms to form a mixture of edge, face, and corner-sharing HTi4Fe2 octahedra. The corner-sharing octahedra tilt angles range from 42–58°. In the third H site, H is bonded to two equivalent Ti and four equivalent Fe atoms to form a mixture of edge and corner-sharing HTi2Fe4 octahedra. The corner-sharing octahedra tilt angles range from 42–48°.