DOE OSTI2020
Ca5Bi6(O2Cl3)4 is Esseneite-like structured and crystallizes in the orthorhombic Immm space group. The structure is three-dimensional. there are three inequivalent Ca2+ sites. In the first Ca2+ site, Ca2+ is bonded in a 4-coordinate geometry to four equivalent O2- and four Cl1- atoms. All Ca–O bond lengths are 2.39 Å. There are two shorter (3.05 Å) and two longer (3.16 Å) Ca–Cl bond lengths. In the second Ca2+ site, Ca2+ is bonded to six Cl1- atoms to form a mixture of corner and edge-sharing CaCl6 octahedra. The corner-sharing octahedra tilt angles range from 0–14°. There are a spread of Ca–Cl bond distances ranging from 2.59–3.02 Å. In the third Ca2+ site, Ca2+ is bonded to six Cl1- atoms to form a mixture of corner and edge-sharing CaCl6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are a spread of Ca–Cl bond distances ranging from 2.67–2.79 Å. There are two inequivalent Bi3+ sites. In the first Bi3+ site, Bi3+ is bonded in a 4-coordinate geometry to four equivalent O2- and one Cl1- atom. There are two shorter (2.28 Å) and two longer (2.30 Å) Bi–O bond lengths. The Bi–Cl bond length is 3.09 Å. In the second Bi3+ site, Bi3+ is bonded in a 4-coordinate geometry to four equivalent O2- and two equivalent Cl1- atoms. All Bi–O bond lengths are 2.30 Å. Both Bi–Cl bond lengths are 3.15 Å. O2- is bonded to one Ca2+ and three Bi3+ atoms to form a mixture of corner and edge-sharing OCaBi3 tetrahedra. There are six inequivalent Cl1- sites. In the first Cl1- site, Cl1- is bonded in a square co-planar geometry to four Ca2+ atoms. In the second Cl1- site, Cl1- is bonded in a 4-coordinate geometry to four Bi3+ atoms. In the third Cl1- site, Cl1- is bonded in a 1-coordinate geometry to two Ca2+ atoms. In the fourth Cl1- site, Cl1- is bonded in a 1-coordinate geometry to three Ca2+ atoms. In the fifth Cl1- site, Cl1- is bonded in a T-shaped geometry to three Ca2+ atoms. In the sixth Cl1- site, Cl1- is bonded in a linear geometry to two equivalent Ca2+ atoms.