Materials Data on Ca(FeO2)2 by Materials Project

CaFe2O4 crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are two inequivalent Ca2+ sites. In the first Ca2+ site, Ca2+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Ca–O bond distances ranging from 2.28–2.70 Å. In the second Ca2+ site, Ca2+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Ca–O bond distances ranging from 2.28–2.91 Å. There are four inequivalent Fe3+ sites. In the first Fe3+ site, Fe3+ is bonded to five O2- atoms to form distorted FeO5 square pyramids that share corners with four FeO6 octahedra and edges with two equivalent FeO5 square pyramids. The corner-sharing octahedra tilt angles range from 51–56°. There are a spread of Fe–O bond distances ranging from 1.95–2.10 Å. In the second Fe3+ site, Fe3+ is bonded to six O2- atoms to form FeO6 octahedra that share corners with four FeO5 square pyramids and edges with four FeO6 octahedra. There are a spread of Fe–O bond distances ranging from 2.01–2.11 Å. In the third Fe3+ site, Fe3+ is bonded to six O2- atoms to form FeO6 octahedra that share corners with four FeO5 square pyramids and edges with four FeO6 octahedra. There are a spread of Fe–O bond distances ranging from 1.98–2.13 Å. In the fourth Fe3+ site, Fe3+ is bonded to five O2- atoms to form distorted FeO5 square pyramids that share corners with four FeO6 octahedra and edges with two equivalent FeO5 square pyramids. The corner-sharing octahedra tilt angles range from 50–56°. There are a spread of Fe–O bond distances ranging from 1.96–2.10 Å. There are eight inequivalent O2- sites. In the first O2- site, O2- is bonded in a 3-coordinate geometry to one Ca2+ and three Fe3+ atoms. In the second O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to one Ca2+ and three Fe3+ atoms. In the third O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to one Ca2+ and three Fe3+ atoms. In the fourth O2- site, O2- is bonded in a 4-coordinate geometry to one Ca2+ and three Fe3+ atoms. In the fifth O2- site, O2- is bonded in a rectangular see-saw-like geometry to two equivalent Ca2+ and two equivalent Fe3+ atoms. In the sixth O2- site, O2- is bonded to two equivalent Ca2+ and three Fe3+ atoms to form distorted edge-sharing OCa2Fe3 trigonal bipyramids. In the seventh O2- site, O2- is bonded in a rectangular see-saw-like geometry to two equivalent Ca2+ and two equivalent Fe3+ atoms. In the eighth O2- site, O2- is bonded to two equivalent Ca2+ and three Fe3+ atoms to form distorted edge-sharing OCa2Fe3 square pyramids.

CaFe₂O₄结晶于三斜晶系P1空间群。其晶体结构为三维骨架结构。体系中存在2个非等效的Ca²+位点：在第一个Ca²+位点中，Ca²+以六配位构型与6个O²-原子成键，Ca–O键的键长分布范围为2.28~2.70 Å；在第二个Ca²+位点中，Ca²+同样以六配位构型与6个O²-原子成键，Ca–O键的键长分布范围为2.28~2.91 Å。体系中存在4个非等效的Fe³+位点：在第一个Fe³+位点中，Fe³+与5个O²-原子配位形成畸变FeO5四方锥（FeO5 square pyramids），该多面体通过共顶点与4个FeO6八面体（FeO6 octahedra）相连，并通过共边与2个等价的FeO5四方锥相连；共顶点八面体的倾斜角范围为51°~56°，Fe–O键的键长分布范围为1.95~2.10 Å。在第二个Fe³+位点中，Fe³+与6个O²-原子配位形成FeO6八面体，该多面体通过共顶点与4个FeO5四方锥相连，并通过共边与4个等价的FeO6八面体相连，Fe–O键的键长分布范围为2.01~2.11 Å。在第三个Fe³+位点中，Fe³+与6个O²-原子配位形成FeO6八面体，该多面体通过共顶点与4个FeO5四方锥相连，并通过共边与4个等价的FeO6八面体相连，Fe–O键的键长分布范围为1.98~2.13 Å。在第四个Fe³+位点中，Fe³+与5个O²-原子配位形成畸变FeO5四方锥（FeO5 square pyramids），该多面体通过共顶点与4个FeO6八面体相连，并通过共边与2个等价的FeO5四方锥相连；共顶点八面体的倾斜角范围为50°~56°，Fe–O键的键长分布范围为1.96~2.10 Å。体系中存在8个非等效的O²-位点：在第一个O²-位点中，O²-以三配位构型与1个Ca²+和3个Fe³+原子成键。在第二个O²-位点中，O²-以畸变矩形跷跷板型配位构型与1个Ca²+和3个Fe³+原子成键。在第三个O²-位点中，O²-以畸变矩形跷跷板型配位构型与1个Ca²+和3个Fe³+原子成键。在第四个O²-位点中，O²-以四配位构型与1个Ca²+和3个Fe³+原子成键。在第五个O²-位点中，O²-以矩形跷跷板型配位构型与2个等价的Ca²+和2个等价的Fe³+原子成键。在第六个O²-位点中，O²-与2个等价的Ca²+和3个Fe³+原子成键，形成畸变的共边OCa2Fe3三角双锥（OCa2Fe3 trigonal bipyramids）。在第七个O²-位点中，O²-以矩形跷跷板型配位构型与2个等价的Ca²+和2个等价的Fe³+原子成键。在第八个O²-位点中，O²-与2个等价的Ca²+和3个Fe³+原子成键，形成畸变的共边OCa2Fe3四方锥（OCa2Fe3 square pyramids）。