DOE OSTI2020
(YCI)2Y2C2IBr crystallizes in the monoclinic Cm space group. The structure is two-dimensional and consists of one Y2C2IBr sheet oriented in the (0, 0, 1) direction and one YCI sheet oriented in the (0, 0, 1) direction. In the Y2C2IBr sheet, there are two inequivalent Y3+ sites. In the first Y3+ site, Y3+ is bonded in a 1-coordinate geometry to five C2- and three equivalent I1- atoms. There are a spread of Y–C bond distances ranging from 2.35–2.71 Å. There are two shorter (3.11 Å) and one longer (3.24 Å) Y–I bond lengths. In the second Y3+ site, Y3+ is bonded in a 8-coordinate geometry to five C2- and three equivalent Br1- atoms. There are a spread of Y–C bond distances ranging from 2.35–2.71 Å. There are two shorter (2.94 Å) and one longer (3.12 Å) Y–Br bond lengths. There are two inequivalent C2- sites. In the first C2- site, C2- is bonded in a 6-coordinate geometry to five Y3+ and one C2- atom. The C–C bond length is 1.33 Å. In the second C2- site, C2- is bonded in a 6-coordinate geometry to five Y3+ and one C2- atom. I1- is bonded in a 3-coordinate geometry to three equivalent Y3+ atoms. Br1- is bonded in a 3-coordinate geometry to three equivalent Y3+ atoms. In the YCI sheet, there are two inequivalent Y3+ sites. In the first Y3+ site, Y3+ is bonded in a 1-coordinate geometry to five C2- and three equivalent I1- atoms. There are a spread of Y–C bond distances ranging from 2.35–2.71 Å. There are two shorter (3.10 Å) and one longer (3.24 Å) Y–I bond lengths. In the second Y3+ site, Y3+ is bonded in a 1-coordinate geometry to five C2- and three equivalent I1- atoms. There are a spread of Y–C bond distances ranging from 2.35–2.70 Å. There are two shorter (3.10 Å) and one longer (3.23 Å) Y–I bond lengths. There are two inequivalent C2- sites. In the first C2- site, C2- is bonded in a 6-coordinate geometry to five Y3+ and one C2- atom. The C–C bond length is 1.33 Å. In the second C2- site, C2- is bonded in a 6-coordinate geometry to five Y3+ and one C2- atom. There are two inequivalent I1- sites. In the first I1- site, I1- is bonded in a 3-coordinate geometry to three equivalent Y3+ atoms. In the second I1- site, I1- is bonded in a 3-coordinate geometry to three equivalent Y3+ atoms.