Materials Data on SrTa2H2O7 by Materials Project

Abstract

H2SrTa2O7 crystallizes in the tetragonal I4/mmm space group. The structure is two-dimensional and consists of two H2SrTa2O7 sheets oriented in the (0, 0, 1) direction. Sr2+ is bonded to twelve O2- atoms to form SrO12 cuboctahedra that share corners with four equivalent SrO12 cuboctahedra, faces with four equivalent SrO12 cuboctahedra, and faces with eight equivalent TaO6 octahedra. There are eight shorter (2.74 Å) and four longer (2.82 Å) Sr–O bond lengths. Ta5+ is bonded to six O2- atoms to form TaO6 octahedra that share corners with five equivalent TaO6 octahedra and faces with four equivalent SrO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 0–12°. There are a spread of Ta–O bond distances ranging from 1.89–2.08 Å. H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.97 Å. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted linear geometry to four equivalent Sr2+ and two equivalent Ta5+ atoms. In the second O2- site, O2- is bonded in a linear geometry to one Ta5+ and one H1+ atom. In the third O2- site, O2- is bonded in a 2-coordinate geometry to two equivalent Sr2+ and two equivalent Ta5+ atoms.