Materials Data on Ba2CuHgO4 by Materials Project
HgBa2CuO4 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 (2.75 Å) and four longer (2.95 Å) Ba–O bond lengths. Cu2+ is bonded in a square co-planar geometry to four equivalent O2- atoms. All Cu–O bond lengths are 1.97 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 four equivalent Ba2+ and two equivalent Cu2+ atoms to form a mixture of distorted corner, edge, and face-sharing OBa4Cu2 octahedra. The corner-sharing octahedral tilt angles are 0°.