Materials Data on Na2TiH4O5 by Materials Project

Na2TiH4O5 crystallizes in the orthorhombic Immm space group. The structure is two-dimensional and consists of two Na2TiH4O5 sheets oriented in the (0, 0, 1) direction. Na1+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Na–O bond distances ranging from 2.18–2.50 Å. Ti4+ is bonded to six O2- atoms to form a mixture of edge and corner-sharing TiO6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are four shorter (1.99 Å) and two longer (2.08 Å) Ti–O bond lengths. H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.98 Å. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded to two equivalent Na1+ and two equivalent Ti4+ atoms to form distorted ONa2Ti2 tetrahedra that share corners with six equivalent ONa2Ti2 tetrahedra, edges with four equivalent ONa4Ti2 octahedra, and an edgeedge with one ONa2Ti2 tetrahedra. In the second O2- site, O2- is bonded to four equivalent Na1+ and two equivalent Ti4+ atoms to form ONa4Ti2 octahedra that share corners with two equivalent ONa4Ti2 octahedra, edges with two equivalent ONa4Ti2 octahedra, and edges with eight equivalent ONa2Ti2 tetrahedra. The corner-sharing octahedral tilt angles are 0°. In the third O2- site, O2- is bonded in a distorted water-like geometry to two equivalent Na1+ and two equivalent H1+ atoms.