Materials Data on BaCo2As6(H2O7)2 by Materials Project

Abstract

BaCo2As6(H2O7)2 crystallizes in the orthorhombic Pnma space group. The structure is two-dimensional and consists of two BaCo2As6(H2O7)2 sheets oriented in the (0, 0, 1) direction. Ba2+ is bonded in a 10-coordinate geometry to ten O2- atoms. There are a spread of Ba–O bond distances ranging from 2.79–3.06 Å. Co2+ is bonded to six O2- atoms to form distorted edge-sharing CoO6 octahedra. There are a spread of Co–O bond distances ranging from 2.08–2.44 Å. There are three inequivalent As3+ sites. In the first As3+ site, As3+ is bonded in a distorted T-shaped geometry to three O2- atoms. There are a spread of As–O bond distances ranging from 1.75–1.91 Å. In the second As3+ site, As3+ is bonded in a distorted trigonal non-coplanar geometry to three O2- atoms. There is one shorter (1.78 Å) and two longer (1.85 Å) As–O bond length. In the third As3+ site, As3+ is bonded in a distorted T-shaped geometry to three O2- atoms. There are a spread of As–O bond distances ranging from 1.78–1.88 Å. There are two inequivalent H1+ sites. In the first H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.99 Å. In the second H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.99 Å. There are nine inequivalent O2- sites. In the first O2- site, O2- is bonded in a trigonal non-coplanar geometry to two equivalent Co2+ and one As3+ atom. In the second O2- site, O2- is bonded in a 3-coordinate geometry to one Ba2+ and two equivalent As3+ atoms. In the third O2- site, O2- is bonded in a water-like geometry to one Ba2+ and two equivalent H1+ atoms. In the fourth O2- site, O2- is bonded in a bent 120 degrees geometry to two As3+ atoms. In the fifth O2- site, O2- is bonded in a water-like geometry to one Ba2+ and two equivalent H1+ atoms. In the sixth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Ba2+ and two equivalent As3+ atoms. In the seventh O2- site, O2- is bonded in a 2-coordinate geometry to one Ba2+, one Co2+, and two As3+ atoms. In the eighth O2- site, O2- is bonded in a 3-coordinate geometry to one Ba2+, two equivalent Co2+, and one As3+ atom. In the ninth O2- site, O2- is bonded in a 3-coordinate geometry to one Ba2+, one Co2+, and one As3+ atom.