Materials Data on Mg2TiBO5 by Materials Project

Mg2TiBO5 crystallizes in the orthorhombic Pbam space group. The structure is three-dimensional. there are three inequivalent Mg2+ sites. In the first Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with two equivalent MgO6 octahedra, edges with two equivalent MgO6 octahedra, and edges with four equivalent TiO6 octahedra. The corner-sharing octahedral tilt angles are 59°. There are two shorter (2.05 Å) and four longer (2.14 Å) Mg–O bond lengths. In the second Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share a cornercorner with one MgO6 octahedra, corners with two equivalent TiO6 octahedra, edges with two equivalent TiO6 octahedra, and edges with four MgO6 octahedra. The corner-sharing octahedra tilt angles range from 59–63°. There are a spread of Mg–O bond distances ranging from 1.99–2.17 Å. In the third Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with four equivalent TiO6 octahedra, edges with two equivalent TiO6 octahedra, and edges with six MgO6 octahedra. The corner-sharing octahedral tilt angles are 15°. There are four shorter (2.10 Å) and two longer (2.13 Å) Mg–O bond lengths. Ti3+ is bonded to six O2- atoms to form TiO6 octahedra that share corners with four MgO6 octahedra, edges with two equivalent TiO6 octahedra, and edges with five MgO6 octahedra. The corner-sharing octahedra tilt angles range from 15–63°. There are a spread of Ti–O bond distances ranging from 2.01–2.15 Å. B3+ is bonded in a trigonal planar geometry to three O2- atoms. There is one shorter (1.38 Å) and two longer (1.40 Å) B–O bond length. There are five inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to two equivalent Mg2+, one Ti3+, and one B3+ atom. In the second O2- site, O2- is bonded in a rectangular see-saw-like geometry to two equivalent Mg2+, one Ti3+, and one B3+ atom. In the third O2- site, O2- is bonded to three Mg2+ and two equivalent Ti3+ atoms to form OMg3Ti2 square pyramids that share corners with two equivalent OMg3Ti2 square pyramids, corners with three equivalent OMg2Ti2 tetrahedra, edges with three equivalent OMg3Ti2 square pyramids, and an edgeedge with one OMg2Ti2 tetrahedra. In the fourth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to three Mg2+ and one B3+ atom. In the fifth O2- site, O2- is bonded to two Mg2+ and two equivalent Ti3+ atoms to form OMg2Ti2 tetrahedra that share corners with three equivalent OMg3Ti2 square pyramids, corners with three equivalent OMg2Ti2 tetrahedra, and an edgeedge with one OMg3Ti2 square pyramid.

Mg₂TiBO₅晶体以正交晶系（orthorhombic）Pbam空间群结晶，整体为三维骨架结构。体系中存在三个不等价的Mg²+离子位点。在第一个Mg²+位点中，Mg²+与六个O²-离子配位形成MgO₆八面体（octahedron），该八面体与两个等价的MgO₆八面体共顶角、与两个等价的MgO₆八面体共棱，同时与四个等价的TiO₆八面体共棱；共顶角八面体的倾斜角为59°，Mg–O键存在两种键长：两个较短键长为2.05 Å，四个较长键长为2.14 Å。在第二个Mg²+位点中，Mg²+与六个O²-离子配位形成MgO₆八面体，该八面体与一个MgO₆八面体共顶角、与两个等价的TiO₆八面体共顶角，与两个等价的TiO₆八面体共棱，同时与四个MgO₆八面体共棱；共顶角八面体的倾斜角介于59°至63°之间，Mg–O键的键长分布范围为1.99 Å至2.17 Å。在第三个Mg²+位点中，Mg²+与六个O²-离子配位形成MgO₆八面体，该八面体与四个等价的TiO₆八面体共顶角、与两个等价的TiO₆八面体共棱，同时与六个MgO₆八面体共棱；共顶角八面体的倾斜角为15°，Mg–O键存在两种键长：四个较短键长为2.10 Å，两个较长键长为2.13 Å。Ti³+与六个O²-离子配位形成TiO₆八面体，该八面体与四个MgO₆八面体共顶角、与两个等价的TiO₆八面体共棱，同时与五个MgO₆八面体共棱；共顶角八面体的倾斜角介于15°至63°之间，Ti–O键的键长分布范围为2.01 Å至2.15 Å。B³+采取平面三角配位模式（trigonal planar geometry）与三个O²-离子成键，B–O键存在两种键长：一个较短键长为1.38 Å，两个较长键长为1.40 Å。体系中存在五个不等价的O²-离子位点：在第一个O²-位点中，O²-采取畸变矩形跷跷板配位几何（distorted rectangular see-saw-like geometry），与两个等价的Mg²+、一个Ti³+以及一个B³+离子配位；在第二个O²-位点中，O²-采取矩形跷跷板配位几何，与两个等价的Mg²+、一个Ti³+以及一个B³+离子配位；在第三个O²-位点中，O²-与三个Mg²+以及两个等价的Ti³+离子配位，形成OMg₃Ti₂四方锥（square pyramid）结构单元，该四方锥与两个等价的OMg₃Ti₂四方锥共顶角、与三个等价的OMg₂Ti₂四面体（tetrahedron）共顶角，同时与三个等价的OMg₃Ti₂四方锥共棱，并与一个OMg₂Ti₂四面体共棱；在第四个O²-位点中，O²-采取畸变矩形跷跷板配位几何，与三个Mg²+以及一个B³+离子配位；在第五个O²-位点中，O²-与两个Mg²+以及两个等价的Ti³+离子配位，形成OMg₂Ti₂四面体结构单元，该四面体与三个等价的OMg₃Ti₂四方锥共顶角、与三个等价的OMg₂Ti₂四面体共顶角，并与一个OMg₃Ti₂四方锥共棱。