Materials Data on Ba2CaCu2HgO6 by Materials Project

Abstract

HgBa2CaCu2O6 crystallizes in the tetragonal P4/mmm space group. The structure is three-dimensional. Ba2+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are four shorter (2.76 Å) and four longer (2.93 Å) Ba–O bond lengths. Ca2+ is bonded in a body-centered cubic geometry to eight equivalent O2- atoms. All Ca–O bond lengths are 2.51 Å. Cu2+ is bonded in a rectangular see-saw-like geometry to four equivalent O2- atoms. All Cu–O bond lengths are 1.95 Å. Hg2+ is bonded in a linear geometry to two equivalent O2- atoms. Both Hg–O bond lengths are 2.01 Å. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded in a 1-coordinate geometry to four equivalent Ba2+ and one Hg2+ atom. In the second O2- site, O2- is bonded to two equivalent Ba2+, two equivalent Ca2+, and two equivalent Cu2+ atoms to form a mixture of distorted edge, face, and corner-sharing OBa2Ca2Cu2 octahedra. The corner-sharing octahedra tilt angles range from 0–67°.