Materials Data on MgAl2O4 by Materials Project

MgAl2O4 is Spinel-like structured and crystallizes in the trigonal R3m space group. The structure is three-dimensional. there are eight inequivalent Mg2+ sites. In the first Mg2+ site, Mg2+ is bonded to four O2- atoms to form MgO4 tetrahedra that share corners with three equivalent MgO6 octahedra and corners with nine AlO6 octahedra. The corner-sharing octahedra tilt angles range from 57–61°. There is three shorter (1.92 Å) and one longer (2.01 Å) Mg–O bond length. In the second Mg2+ site, Mg2+ is bonded to four O2- atoms to form MgO4 tetrahedra that share corners with three equivalent MgO6 octahedra and corners with nine AlO6 octahedra. The corner-sharing octahedra tilt angles range from 56–63°. There is three shorter (1.93 Å) and one longer (1.97 Å) Mg–O bond length. In the third Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with three equivalent MgO4 tetrahedra, corners with three equivalent AlO4 tetrahedra, and edges with six AlO6 octahedra. There are three shorter (2.00 Å) and three longer (2.10 Å) Mg–O bond lengths. In the fourth Mg2+ site, Mg2+ is bonded to four O2- atoms to form MgO4 tetrahedra that share corners with twelve AlO6 octahedra. The corner-sharing octahedra tilt angles range from 58–60°. There is one shorter (1.93 Å) and three longer (1.96 Å) Mg–O bond length. In the fifth Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with three equivalent MgO4 tetrahedra, corners with three equivalent AlO4 tetrahedra, and edges with six AlO6 octahedra. There are three shorter (2.03 Å) and three longer (2.08 Å) Mg–O bond lengths. In the sixth Mg2+ site, Mg2+ is bonded to four O2- atoms to form MgO4 tetrahedra that share corners with twelve AlO6 octahedra. The corner-sharing octahedra tilt angles range from 59–60°. There is one shorter (1.95 Å) and three longer (1.96 Å) Mg–O bond length. In the seventh Mg2+ site, Mg2+ is bonded to four O2- atoms to form MgO4 tetrahedra that share corners with twelve AlO6 octahedra. The corner-sharing octahedra tilt angles range from 58–62°. There is three shorter (1.97 Å) and one longer (2.00 Å) Mg–O bond length. In the eighth Mg2+ site, Mg2+ is bonded to four O2- atoms to form MgO4 tetrahedra that share corners with twelve AlO6 octahedra. The corner-sharing octahedra tilt angles range from 59–62°. There is three shorter (1.96 Å) and one longer (2.01 Å) Mg–O bond length. There are eight inequivalent Al3+ sites. In the first Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with three MgO4 tetrahedra, corners with three AlO4 tetrahedra, edges with two MgO6 octahedra, and edges with four equivalent AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.88–2.04 Å. In the second Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share a cornercorner with one AlO4 tetrahedra, corners with five MgO4 tetrahedra, an edgeedge with one MgO6 octahedra, and edges with five AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.88–2.07 Å. In the third Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with six MgO4 tetrahedra and edges with six AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.92–1.95 Å. In the fourth Al3+ site, Al3+ is bonded to four O2- atoms to form AlO4 tetrahedra that share corners with three equivalent MgO6 octahedra and corners with nine AlO6 octahedra. The corner-sharing octahedra tilt angles range from 55–60°. There is three shorter (1.84 Å) and one longer (1.85 Å) Al–O bond length. In the fifth Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with six MgO4 tetrahedra and edges with six AlO6 octahedra. There is three shorter (1.91 Å) and three longer (1.95 Å) Al–O bond length. In the sixth Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with two equivalent AlO4 tetrahedra, corners with four MgO4 tetrahedra, an edgeedge with one MgO6 octahedra, and edges with five AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.92–1.98 Å. In the seventh Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with six MgO4 tetrahedra and edges with six AlO6 octahedra. There is three shorter (1.92 Å) and three longer (1.94 Å) Al–O bond length. In the eighth Al3+ site, Al3+ is bonded to four O2- atoms to form AlO4 tetrahedra that share corners with three equivalent MgO6 octahedra and corners with nine AlO6 octahedra. The corner-sharing octahedra tilt angles range from 55–61°. There is three shorter (1.83 Å) and one longer (1.86 Å) Al–O bond length. There are sixteen inequivalent O2- sites. In the first O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Mg2+ and two equivalent Al3+ atoms. In the second O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to one Mg2+ and three equivalent Al3+ atoms. In the third O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to one Mg2+ and three Al3+ atoms. In the fourth O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Mg2+ and two equivalent Al3+ atoms. In the fifth O2- site, O2- is bonded to one Mg2+ and three equivalent Al3+ atoms to form distorted corner-sharing OMgAl3 trigonal pyramids. In the sixth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to four Al3+ atoms. In the seventh O2- site, O2- is bonded to one Mg2+ and three Al3+ atoms to form a mixture of distorted edge and corner-sharing OMgAl3 tetrahedra. In the eighth O2- site, O2- is bonded to one Mg2+ and three Al3+ atoms to form a mixture of distorted edge and corner-sharing OMgAl3 trigonal pyramids. In the ninth O2- site, O2- is bonded to one Mg2+ and three equivalent Al3+ atoms to form a mixture of distorted edge and corner-sharing OMgAl3 trigonal pyramids. In the tenth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to four Al3+ atoms. In the eleventh O2- site, O2- is bonded to one Mg2+ and three Al3+ atoms to form a mixture of distorted edge and corner-sharing OMgAl3 trigonal pyramids. In the twelfth O2- site, O2- is bonded to one Mg2+ and three Al3+ atoms to form a mixture of distorted edge and corner-sharing OMgAl3 trigonal pyramids. In the thirteenth O2- site, O2- is bonded to one Mg2+ and three equivalent Al3+ atoms to form a mixture of distorted edge and corner-sharing OMgAl3 trigonal pyramids. In the fourteenth O2- site, O2- is bonded to one Mg2+ and three equivalent Al3+ atoms to form a mixture of distorted edge and corner-sharing OMgAl3 trigonal pyramids. In the fifteenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Mg2+ and three Al3+ atoms. In the sixteenth O2- site, O2- is bonded to one Mg2+ and three equivalent Al3+ atoms to form corner-sharing OMgAl3 tetrahedra.

铝酸镁（MgAl₂O₄）具有类尖晶石晶体结构，结晶于三方晶系R3m空间群。该结构为三维网状结构，存在8种不等价Mg²⁺晶位。在第1个Mg²⁺晶位中，Mg²⁺与4个O²⁻成键，形成MgO₄四面体，该四面体与3个等价的MgO₆八面体及9个AlO₆八面体通过共顶点相连。共顶点八面体的倾斜角范围为57°~61°，Mg-O键长存在3个较短键长（1.92 Å）与1个较长键长（2.01 Å）。在第2个Mg²⁺晶位中，Mg²⁺与4个O²⁻成键，形成MgO₄四面体，该四面体与3个等价的MgO₆八面体及9个AlO₆八面体通过共顶点相连。共顶点八面体的倾斜角范围为56°~63°，Mg-O键长存在3个较短键长（1.93 Å）与1个较长键长（1.97 Å）。在第3个Mg²⁺晶位中，Mg²⁺与6个O²⁻成键，形成MgO₆八面体，该八面体与3个等价的MgO₄四面体、3个等价的AlO₄四面体共顶点相连，并与6个AlO₆八面体共边相连。Mg-O键长存在3个较短键长（2.00 Å）与3个较长键长（2.10 Å）。在第4个Mg²⁺晶位中，Mg²⁺与4个O²⁻成键，形成MgO₄四面体，该四面体与12个AlO₆八面体通过共顶点相连。共顶点八面体的倾斜角范围为58°~60°，Mg-O键长存在1个较短键长（1.93 Å）与3个较长键长（1.96 Å）。在第5个Mg²⁺晶位中，Mg²⁺与6个O²⁻成键，形成MgO₆八面体，该八面体与3个等价的MgO₄四面体、3个等价的AlO₄四面体共顶点相连，并与6个AlO₆八面体共边相连。Mg-O键长存在3个较短键长（2.03 Å）与3个较长键长（2.08 Å）。在第6个Mg²⁺晶位中，Mg²⁺与4个O²⁻成键，形成MgO₄四面体，该四面体与12个AlO₆八面体通过共顶点相连。共顶点八面体的倾斜角范围为59°~60°，Mg-O键长存在1个较短键长（1.95 Å）与3个较长键长（1.96 Å）。在第7个Mg²⁺晶位中，Mg²⁺与4个O²⁻成键，形成MgO₄四面体，该四面体与12个AlO₆八面体通过共顶点相连。共顶点八面体的倾斜角范围为58°~62°，Mg-O键长存在3个较短键长（1.97 Å）与1个较长键长（2.00 Å）。在第8个Mg²⁺晶位中，Mg²⁺与4个O²⁻成键，形成MgO₄四面体，该四面体与12个AlO₆八面体通过共顶点相连。共顶点八面体的倾斜角范围为59°~62°，Mg-O键长存在3个较短键长（1.96 Å）与1个较长键长（2.01 Å）。

存在8种不等价Al³⁺晶位。在第1个Al³⁺晶位中，Al³⁺与6个O²⁻成键，形成AlO₆八面体，该八面体与3个MgO₄四面体、3个AlO₄四面体共顶点相连，并与2个MgO₆八面体及4个等价的AlO₆八面体共边相连。Al-O键距分布范围为1.88~2.04 Å。在第2个Al³⁺晶位中，Al³⁺与6个O²⁻成键，形成AlO₆八面体，该八面体与1个AlO₄四面体共1个顶点、与5个MgO₄四面体共顶点相连，并与1个MgO₆八面体共1条边、与5个等价的AlO₆八面体共边相连。Al-O键距分布范围为1.88~2.07 Å。在第3个Al³⁺晶位中，Al³⁺与6个O²⁻成键，形成AlO₆八面体，该八面体与6个MgO₄四面体共顶点相连，并与6个AlO₆八面体共边相连。Al-O键距分布范围为1.92~1.95 Å。在第4个Al³⁺晶位中，Al³⁺与4个O²⁻成键，形成AlO₄四面体，该四面体与3个等价的MgO₆八面体及9个AlO₆八面体通过共顶点相连。共顶点八面体的倾斜角范围为55°~60°，Al-O键长存在3个较短键长（1.84 Å）与1个较长键长（1.85 Å）。在第5个Al³⁺晶位中，Al³⁺与6个O²⁻成键，形成AlO₆八面体，该八面体与6个MgO₄四面体共顶点相连，并与6个AlO₆八面体共边相连。Al-O键长存在3个较短键长（1.91 Å）与3个较长键长（1.95 Å）。在第6个Al³⁺晶位中，Al³⁺与6个O²⁻成键，形成AlO₆八面体，该八面体与2个等价的AlO₄四面体、4个MgO₄四面体共顶点相连，并与1个MgO₆八面体共1条边、与5个等价的AlO₆八面体共边相连。Al-O键距分布范围为1.92~1.98 Å。在第7个Al³⁺晶位中，Al³⁺与6个O²⁻成键，形成AlO₆八面体，该八面体与6个MgO₄四面体共顶点相连，并与6个AlO₆八面体共边相连。Al-O键长存在3个较短键长（1.92 Å）与3个较长键长（1.94 Å）。在第8个Al³⁺晶位中，Al³⁺与4个O²⁻成键，形成AlO₄四面体，该四面体与3个等价的MgO₆八面体及9个AlO₆八面体通过共顶点相连。共顶点八面体的倾斜角范围为55°~61°，Al-O键长存在3个较短键长（1.83 Å）与1个较长键长（1.86 Å）。

存在16种不等价O²⁻晶位。在第1个O²⁻晶位中，O²⁻以矩形跷跷板状配位几何与2个Mg²⁺及2个等价的Al³⁺成键。在第2个O²⁻晶位中，O²⁻以畸变矩形跷跷板状配位几何与1个Mg²⁺及3个等价的Al³⁺成键。在第3个O²⁻晶位中，O²⁻以畸变矩形跷跷板状配位几何与1个Mg²⁺及3个Al³⁺成键。在第4个O²⁻晶位中，O²⁻以矩形跷跷板状配位几何与2个Mg²⁺及2个等价的Al³⁺成键。在第5个O²⁻晶位中，O²⁻与1个Mg²⁺及3个等价的Al³⁺成键，形成畸变共顶点OMgAl₃三角锥结构。在第6个O²⁻晶位中，O²⁻以畸变矩形跷跷板状配位几何与4个Al³⁺成键。在第7个O²⁻晶位中，O²⁻与1个Mg²⁺及3个Al³⁺成键，形成畸变共边与共顶点混合型OMgAl₃四面体结构。在第8个O²⁻晶位中，O²⁻与1个Mg²⁺及3个Al³⁺成键，形成畸变共边与共顶点混合型OMgAl₃三角锥结构。在第9个O²⁻晶位中，O²⁻与1个Mg²⁺及3个等价的Al³⁺成键，形成畸变共边与共顶点混合型OMgAl₃三角锥结构。在第10个O²⁻晶位中，O²⁻以畸变矩形跷跷板状配位几何与4个Al³⁺成键。在第11个O²⁻晶位中，O²⁻与1个Mg²⁺及3个Al³⁺成键，形成畸变共边与共顶点混合型OMgAl₃三角锥结构。在第12个O²⁻晶位中，O²⁻与1个Mg²⁺及3个Al³⁺成键，形成畸变共边与共顶点混合型OMgAl₃三角锥结构。在第13个O²⁻晶位中，O²⁻与1个Mg²⁺及3个等价的Al³⁺成键，形成畸变共边与共顶点混合型OMgAl₃三角锥结构。在第14个O²⁻晶位中，O²⁻与1个Mg²⁺及3个等价的Al³⁺成键，形成畸变共边与共顶点混合型OMgAl₃三角锥结构。在第15个O²⁻晶位中，O²⁻以矩形跷跷板状配位几何与1个Mg²⁺及3个Al³⁺成键。在第16个O²⁻晶位中，O²⁻与1个Mg²⁺及3个等价的Al³⁺成键，形成共顶点OMgAl₃四面体结构。