DOE OSTI2020
Ca(O2I)4Hg crystallizes in the tetragonal P4_2/mbc space group. The structure is three-dimensional and consists of eight mercury molecules and one Ca(O2I)4 framework. In the Ca(O2I)4 framework, there are two inequivalent Ca sites. In the first Ca site, Ca is bonded in a 8-coordinate geometry to eight O atoms. There are four shorter (2.44 Å) and four longer (2.53 Å) Ca–O bond lengths. In the second Ca site, Ca is bonded in a 8-coordinate geometry to eight O atoms. There are four shorter (2.51 Å) and four longer (2.69 Å) Ca–O bond lengths. There are four inequivalent O sites. In the first O site, O is bonded in a bent 120 degrees geometry to one Ca and one I atom. The O–I bond length is 1.83 Å. In the second O site, O is bonded in a distorted trigonal planar geometry to one Ca and two I atoms. There are one shorter (1.89 Å) and one longer (2.52 Å) O–I bond lengths. In the third O site, O is bonded in a bent 120 degrees geometry to one Ca and one I atom. The O–I bond length is 1.89 Å. In the fourth O site, O is bonded in a bent 120 degrees geometry to one Ca and one I atom. The O–I bond length is 1.84 Å. There are three inequivalent I sites. In the first I site, I is bonded in a water-like geometry to two equivalent O atoms. In the second I site, I is bonded in a water-like geometry to two equivalent O atoms. In the third I site, I is bonded in a distorted water-like geometry to three O atoms.