Materials Data on Ca(CO2)2 by Materials Project

CaC2O4 crystallizes in the monoclinic P2/m space group. The structure is two-dimensional and consists of one CaC2O4 sheet oriented in the (1, 0, 0) direction. there are two inequivalent Ca2+ sites. In the first Ca2+ site, Ca2+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Ca–O bond distances ranging from 2.23–2.56 Å. In the second Ca2+ site, Ca2+ is bonded in a 6-coordinate geometry to seven O2- atoms. There are a spread of Ca–O bond distances ranging from 2.29–3.04 Å. There are four inequivalent C3+ sites. In the first C3+ site, C3+ is bonded in a bent 120 degrees geometry to two O2- atoms. There is one shorter (1.26 Å) and one longer (1.27 Å) C–O bond length. In the second C3+ site, C3+ is bonded in a bent 120 degrees geometry to two equivalent O2- atoms. Both C–O bond lengths are 1.27 Å. In the third C3+ site, C3+ is bonded in a bent 120 degrees geometry to two equivalent O2- atoms. Both C–O bond lengths are 1.27 Å. In the fourth C3+ site, C3+ is bonded in a single-bond geometry to one O2- atom. The C–O bond length is 1.33 Å. There are six inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted single-bond geometry to one Ca2+ and one C3+ atom. In the second O2- site, O2- is bonded in a 3-coordinate geometry to two Ca2+ and one C3+ atom. In the third O2- site, O2- is bonded in a 3-coordinate geometry to two equivalent Ca2+ and one C3+ atom. In the fourth O2- site, O2- is bonded in a 3-coordinate geometry to two Ca2+ and one C3+ atom. In the fifth O2- site, O2- is bonded in a distorted single-bond geometry to two equivalent Ca2+, one C3+, and one O2- atom. The O–O bond length is 1.45 Å. In the sixth O2- site, O2- is bonded in a distorted L-shaped geometry to one Ca2+ and one O2- atom.

CaC₂O₄晶体属于单斜晶系P2/m空间群。其结构为二维结构，由一个沿(1, 0, 0)方向排列的CaC₂O₄片层构成。结构中存在两个不等价Ca²+位点：第一个Ca²+位点中，Ca²+以七配位几何构型与七个O²-原子键合，Ca-O键长范围为2.23–2.56 Å；第二个Ca²+位点中，Ca²+以六配位几何构型与七个O²-原子键合，则Ca-O键长范围为2.29–3.04 Å。此外，结构包含四个不等价C³+位点：第一个C³+位点中C³+以弯曲120°几何构型与两个O²-原子键合，C-O键长分别为1.26 Å（较短）和1.27 Å（较长）；第二个C³+位点中C³+以弯曲120°几何构型与两个等价O²-原子键合，所有C-O键长均为1.27 Å；第三个C³+位点情况与第二个一致；第四个C³+位点中C³+以单键构型与一个O²-原子键合，则C-O键长为1.33 Å。结构还存在六个不等价O²-位点：第一个O²-位点中O²-以扭曲单键构型与一個Ca²+原子和一個C³+原子键合；第二个O²-位点中O²-以三配位构型与两个Ca²+原子和一個C³+原子键合；第三个O²-位点中O²-以三配位构型与两个等价Ca²+原子和一個C³+原子键合；第四个O²-位点情况与第二个相同；第五个O²-位点中O²-以扭曲单键构型与两个等价Ca²+原子、一個C³+原子及一個O²-原子键合，O-O键长为1.45 Å；第六个O²-位点中O²-以扭曲L形构型与一個Ca²+原子和一個O²-原子键合。