Materials Data on SrTi2O5 by Materials Project

TiO2SrTiO3 crystallizes in the orthorhombic Cmm2 space group. The structure is two-dimensional and consists of one TiO2SrTiO3 sheet oriented in the (0, 0, 1) direction. there are three inequivalent Sr2+ sites. In the first Sr2+ site, Sr2+ is bonded in a 4-coordinate geometry to four O2- atoms. There are two shorter (2.52 Å) and two longer (2.60 Å) Sr–O bond lengths. In the second Sr2+ site, Sr2+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Sr–O bond distances ranging from 2.51–2.65 Å. In the third Sr2+ site, Sr2+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Sr–O bond distances ranging from 2.55–2.77 Å. There are three inequivalent Ti4+ sites. In the first Ti4+ site, Ti4+ is bonded to six O2- atoms to form distorted TiO6 octahedra that share corners with four equivalent TiO6 octahedra and an edgeedge with one TiO5 trigonal bipyramid. The corner-sharing octahedra tilt angles range from 14–16°. There are a spread of Ti–O bond distances ranging from 1.85–2.23 Å. In the second Ti4+ site, Ti4+ is bonded in a 5-coordinate geometry to five O2- atoms. There are a spread of Ti–O bond distances ranging from 1.82–2.36 Å. In the third Ti4+ site, Ti4+ is bonded to five O2- atoms to form distorted TiO5 trigonal bipyramids that share a cornercorner with one TiO5 trigonal bipyramid and edges with two equivalent TiO6 octahedra. There are a spread of Ti–O bond distances ranging from 1.65–2.09 Å. There are nine inequivalent O2- sites. In the first O2- site, O2- is bonded in a bent 150 degrees geometry to two equivalent Ti4+ atoms. In the second O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to four Ti4+ atoms. In the third O2- site, O2- is bonded in a single-bond geometry to one Ti4+ atom. In the fourth O2- site, O2- is bonded in a 5-coordinate geometry to two Sr2+ and three Ti4+ atoms. In the fifth O2- site, O2- is bonded in a distorted single-bond geometry to two Sr2+ and one Ti4+ atom. In the sixth O2- site, O2- is bonded in a distorted see-saw-like geometry to two Sr2+ and two equivalent Ti4+ atoms. In the seventh O2- site, O2- is bonded in a 5-coordinate geometry to two Sr2+ and three Ti4+ atoms. In the eighth O2- site, O2- is bonded in a trigonal non-coplanar geometry to three Ti4+ atoms. In the ninth O2- site, O2- is bonded in a distorted see-saw-like geometry to two equivalent Sr2+ and two equivalent Ti4+ atoms.

TiO₂SrTiO₃晶体属于正交晶系（orthorhombic）的Cmm2空间群。该结构为二维结构，包含一片沿(0, 0, 1)方向取向的TiO₂SrTiO₃片层。体系中存在3个不等价的Sr²+配位位点。在第一个Sr²+位点中，Sr²+以4配位几何构型与4个O²-原子成键，Sr–O键长分为两组，分别为2.52 Å（较短）与2.60 Å（较长）。在第二个Sr²+位点中，Sr²+以6配位几何构型与6个O²-原子成键，Sr–O键距分布范围为2.51~2.65 Å。在第三个Sr²+位点中，Sr²+以8配位几何构型与8个O²-原子成键，Sr–O键距分布范围为2.55~2.77 Å。体系中存在3个不等价的Ti⁴+配位位点。在第一个Ti⁴+位点中，Ti⁴+与6个O²-原子成键，形成畸变的TiO₆八面体（octahedra）；该八面体与4个等价的TiO₆八面体通过顶角相连，并与1个TiO₅三角双锥（trigonal bipyramid）通过棱边相连。顶角共享八面体的倾斜角范围为14°~16°，Ti–O键距分布范围为1.85~2.23 Å。在第二个Ti⁴+位点中，Ti⁴+以5配位几何构型与5个O²-原子成键，Ti–O键距分布范围为1.82~2.36 Å。在第三个Ti⁴+位点中，Ti⁴+与5个O²-原子成键，形成畸变的TiO₅三角双锥；该三角双锥与1个TiO₅三角双锥通过顶角相连，并与2个等价的TiO₆八面体通过棱边相连。Ti–O键距分布范围为1.65~2.09 Å。体系中存在9个不等价的O²-配位位点。在第一个O²-位点中，O²-以150°弯曲几何构型与2个等价的Ti⁴+原子成键。在第二个O²-位点中，O²-以畸变矩形跷跷板状几何构型与4个Ti⁴+原子成键。在第三个O²-位点中，O²-以单键几何构型与1个Ti⁴+原子成键。在第四个O²-位点中，O²-以5配位几何构型与2个Sr²+原子及3个Ti⁴+原子成键。在第五个O²-位点中，O²-以畸变单键几何构型与2个Sr²+原子及1个Ti⁴+原子成键。在第六个O²-位点中，O²-以畸变跷跷板状几何构型与2个Sr²+原子及2个等价的Ti⁴+原子成键。在第七个O²-位点中，O²-以5配位几何构型与2个Sr²+原子及3个Ti⁴+原子成键。在第八个O²-位点中，O²-以三角非共面几何构型与3个Ti⁴+原子成键。在第九个O²-位点中，O²-以畸变跷跷板状几何构型与2个等价的Sr²+原子及2个等价的Ti⁴+原子成键。