Materials Data on Mg4Sb2O9 by Materials Project

Mg4Sb2O9 is Ilmenite-like structured and crystallizes in the triclinic P-1 space group. The structure is three-dimensional. there are four inequivalent Mg2+ sites. In the first Mg2+ site, Mg2+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Mg–O bond distances ranging from 2.01–2.42 Å. In the second Mg2+ site, Mg2+ is bonded to six O2- atoms to form distorted MgO6 octahedra that share corners with six MgO6 octahedra, edges with three SbO6 octahedra, and a faceface with one MgO6 octahedra. The corner-sharing octahedra tilt angles range from 44–64°. There are a spread of Mg–O bond distances ranging from 2.03–2.25 Å. In the third Mg2+ site, Mg2+ is bonded to six O2- atoms to form distorted MgO6 octahedra that share corners with two equivalent MgO6 octahedra, corners with seven SbO6 octahedra, edges with three MgO6 octahedra, and a faceface with one MgO6 octahedra. The corner-sharing octahedra tilt angles range from 43–64°. There are a spread of Mg–O bond distances ranging from 2.05–2.23 Å. In the fourth Mg2+ site, Mg2+ is bonded to six O2- atoms to form distorted MgO6 octahedra that share corners with four equivalent MgO6 octahedra, corners with five SbO6 octahedra, edges with two equivalent MgO6 octahedra, and a faceface with one SbO6 octahedra. The corner-sharing octahedra tilt angles range from 44–63°. There are a spread of Mg–O bond distances ranging from 2.04–2.22 Å. There are two inequivalent Sb5+ sites. In the first Sb5+ site, Sb5+ is bonded to six O2- atoms to form SbO6 octahedra that share corners with four MgO6 octahedra, an edgeedge with one MgO6 octahedra, and edges with two equivalent SbO6 octahedra. The corner-sharing octahedra tilt angles range from 46–63°. There are a spread of Sb–O bond distances ranging from 1.93–2.14 Å. In the second Sb5+ site, Sb5+ is bonded to six O2- atoms to form SbO6 octahedra that share corners with eight MgO6 octahedra, an edgeedge with one SbO6 octahedra, edges with two equivalent MgO6 octahedra, and a faceface with one MgO6 octahedra. The corner-sharing octahedra tilt angles range from 43–60°. There are a spread of Sb–O bond distances ranging from 1.97–2.15 Å. There are nine inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted see-saw-like geometry to three Mg2+ and one Sb5+ atom. In the second O2- site, O2- is bonded in a distorted see-saw-like geometry to three Mg2+ and one Sb5+ atom. In the third O2- site, O2- is bonded to three Mg2+ and one Sb5+ atom to form a mixture of distorted edge and corner-sharing OMg3Sb trigonal pyramids. In the fourth O2- site, O2- is bonded to two equivalent Mg2+ and two equivalent Sb5+ atoms to form distorted OMg2Sb2 trigonal pyramids that share corners with eight OMg3Sb trigonal pyramids and edges with three OMg2Sb2 trigonal pyramids. In the fifth O2- site, O2- is bonded to three Mg2+ and one Sb5+ atom to form distorted OMg3Sb trigonal pyramids that share corners with seven OMg3Sb trigonal pyramids and an edgeedge with one OMg2Sb2 trigonal pyramid. In the sixth O2- site, O2- is bonded in a distorted see-saw-like geometry to three Mg2+ and one Sb5+ atom. In the seventh O2- site, O2- is bonded to two Mg2+ and two equivalent Sb5+ atoms to form a mixture of distorted edge and corner-sharing OMg2Sb2 trigonal pyramids. In the eighth O2- site, O2- is bonded to two Mg2+ and two equivalent Sb5+ atoms to form a mixture of distorted edge and corner-sharing OMg2Sb2 trigonal pyramids. In the ninth O2- site, O2- is bonded in a distorted see-saw-like geometry to three Mg2+ and one Sb5+ atom.

Mg₄Sb₂O₉为钛铁矿型（Ilmenite-like）结构，结晶于三斜晶系P-1空间群（triclinic P-1 space group）。该结构为三维框架结构。体系中存在四个不等价的Mg²+位点。在第一个Mg²+位点中，Mg²+以六配位几何（coordinate geometry）与六个O²-原子配位，Mg-O键长分布范围为2.01~2.42 Å。在第二个Mg²+位点中，Mg²+与六个O²-原子配位形成畸变的MgO₆八面体（octahedra），该八面体与六个MgO₆八面体共角顶相连、与三个SbO₆八面体共边相连，还与一个MgO₆八面体共面相连。共角顶八面体的倾斜角范围为44°~64°，Mg-O键长分布范围为2.03~2.25 Å。在第三个Mg²+位点中，Mg²+与六个O²-原子配位形成畸变的MgO₆八面体，该八面体与两个等价的MgO₆八面体共角顶、与七个SbO₆八面体共角顶，与三个MgO₆八面体共边相连，还与一个MgO₆八面体共面相连。共角顶八面体的倾斜角范围为43°~64°，Mg-O键长分布范围为2.05~2.23 Å。在第四个Mg²+位点中，Mg²+与六个O²-原子配位形成畸变的MgO₆八面体，该八面体与四个等价的MgO₆八面体共角顶、与五个SbO₆八面体共角顶，与两个等价的MgO₆八面体共边相连，还与一个SbO₆八面体共面相连。共角顶八面体的倾斜角范围为44°~63°，Mg-O键长分布范围为2.04~2.22 Å。体系中存在两个不等价的Sb⁵+位点。在第一个Sb⁵+位点中，Sb⁵+与六个O²-原子配位形成SbO₆八面体，该八面体与四个MgO₆八面体共角顶相连、与一个MgO₆八面体共边相连，还与两个等价的SbO₆八面体共边相连。共角顶八面体的倾斜角范围为46°~63°，Sb-O键长分布范围为1.93~2.14 Å。在第二个Sb⁵+位点中，Sb⁵+与六个O²-原子配位形成SbO₆八面体，该八面体与八个MgO₆八面体共角顶相连、与一个SbO₆八面体共边相连，与两个等价的MgO₆八面体共边相连，还与一个MgO₆八面体共面相连。共角顶八面体的倾斜角范围为43°~60°，Sb-O键长分布范围为1.97~2.15 Å。体系中存在九个不等价的O²-位点。在第一个O²-位点中，O²-以畸变跷跷板型几何与三个Mg²+和一个Sb⁵+原子配位。在第二个O²-位点中，O²-以畸变跷跷板型几何与三个Mg²+和一个Sb⁵+原子配位。在第三个O²-位点中，O²-与三个Mg²+和一个Sb⁵+原子配位，形成兼具畸变共边和共角顶连接的OMg₃Sb三角锥（trigonal pyramids）结构。在第四个O²-位点中，O²-与两个等价的Mg²+和两个等价的Sb⁵+原子配位，形成畸变的OMg₂Sb₂三角锥，该三角锥与八个OMg₃Sb三角锥共角顶相连、与三个OMg₂Sb₂三角锥共边相连。在第五个O²-位点中，O²-与三个Mg²+和一个Sb⁵+原子配位，形成畸变的OMg₃Sb三角锥，该三角锥与七个OMg₃Sb三角锥共角顶相连、与一个OMg₂Sb₂三角锥共边相连。在第六个O²-位点中，O²-以畸变跷跷板型几何与三个Mg²+和一个Sb⁵+原子配位。在第七个O²-位点中，O²-与两个Mg²+和两个等价的Sb⁵+原子配位，形成兼具畸变共边和共角顶连接的OMg₂Sb₂三角锥结构。在第八个O²-位点中，O²-与两个Mg²+和两个等价的Sb⁵+原子配位，形成兼具畸变共边和共角顶连接的OMg₂Sb₂三角锥结构。在第九个O²-位点中，O²-以畸变跷跷板型几何与三个Mg²+和一个Sb⁵+原子配位。