Materials Data on Mg(NiO2)2 by Materials Project

Mg(NiO2)2 is Spinel-like structured and crystallizes in the monoclinic Cm 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 MgO6 octahedra and corners with nine NiO6 octahedra. The corner-sharing octahedra tilt angles range from 54–63°. There are a spread of Mg–O bond distances ranging from 1.96–2.00 Å. In the second Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with three MgO4 tetrahedra, corners with three NiO4 tetrahedra, and edges with six NiO6 octahedra. There are a spread of Mg–O bond distances ranging from 2.03–2.06 Å. In the third Mg2+ site, Mg2+ is bonded to four O2- atoms to form MgO4 tetrahedra that share corners with three MgO6 octahedra and corners with nine NiO6 octahedra. The corner-sharing octahedra tilt angles range from 56–62°. There are a spread of Mg–O bond distances ranging from 1.96–2.00 Å. In the fourth Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with two equivalent MgO4 tetrahedra, corners with four NiO4 tetrahedra, an edgeedge with one MgO6 octahedra, and edges with five NiO6 octahedra. There are a spread of Mg–O bond distances ranging from 2.02–2.06 Å. In the fifth Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with six NiO4 tetrahedra, edges with two MgO6 octahedra, and edges with four equivalent NiO6 octahedra. There are a spread of Mg–O bond distances ranging from 2.03–2.07 Å. In the sixth Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with six NiO4 tetrahedra, edges with two MgO6 octahedra, and edges with four NiO6 octahedra. There are a spread of Mg–O bond distances ranging from 2.04–2.08 Å. In the seventh Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share a cornercorner with one MgO4 tetrahedra, corners with five NiO4 tetrahedra, an edgeedge with one MgO6 octahedra, and edges with five NiO6 octahedra. There are a spread of Mg–O bond distances ranging from 2.02–2.07 Å. In the eighth Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with six NiO4 tetrahedra, edges with two MgO6 octahedra, and edges with four NiO6 octahedra. There are a spread of Mg–O bond distances ranging from 2.02–2.07 Å. There are twelve inequivalent Ni3+ sites. In the first Ni3+ site, Ni3+ is bonded to six O2- atoms to form NiO6 octahedra that share corners with three MgO4 tetrahedra, corners with three NiO4 tetrahedra, edges with two equivalent MgO6 octahedra, and edges with four NiO6 octahedra. There are a spread of Ni–O bond distances ranging from 1.90–2.06 Å. In the second Ni3+ site, Ni3+ is bonded to six O2- atoms to form NiO6 octahedra that share corners with three equivalent MgO4 tetrahedra, corners with three equivalent NiO4 tetrahedra, edges with two MgO6 octahedra, and edges with four NiO6 octahedra. There are a spread of Ni–O bond distances ranging from 1.91–2.06 Å. In the third Ni3+ site, Ni3+ is bonded to four O2- atoms to form NiO4 tetrahedra that share corners with six MgO6 octahedra and corners with six NiO6 octahedra. The corner-sharing octahedra tilt angles range from 54–59°. There is two shorter (1.88 Å) and two longer (1.90 Å) Ni–O bond length. In the fourth Ni3+ site, Ni3+ is bonded to six O2- atoms to form NiO6 octahedra that share corners with two equivalent MgO4 tetrahedra, corners with four NiO4 tetrahedra, edges with three MgO6 octahedra, and edges with three NiO6 octahedra. There are a spread of Ni–O bond distances ranging from 1.87–2.02 Å. In the fifth Ni3+ site, Ni3+ is bonded to four O2- atoms to form NiO4 tetrahedra that share corners with three MgO6 octahedra and corners with nine NiO6 octahedra. The corner-sharing octahedra tilt angles range from 55–61°. There are a spread of Ni–O bond distances ranging from 1.89–1.94 Å. In the sixth Ni3+ site, Ni3+ is bonded to four O2- atoms to form NiO4 tetrahedra that share corners with six MgO6 octahedra and corners with six NiO6 octahedra. The corner-sharing octahedra tilt angles range from 53–59°. There are a spread of Ni–O bond distances ranging from 1.83–1.88 Å. In the seventh Ni3+ site, Ni3+ is bonded to six O2- atoms to form NiO6 octahedra that share corners with six NiO4 tetrahedra, edges with two equivalent NiO6 octahedra, and edges with four MgO6 octahedra. There are a spread of Ni–O bond distances ranging from 1.87–2.02 Å. In the eighth Ni3+ site, Ni3+ is bonded to four O2- atoms to form NiO4 tetrahedra that share corners with six MgO6 octahedra and corners with six NiO6 octahedra. The corner-sharing octahedra tilt angles range from 54–62°. There is three shorter (1.91 Å) and one longer (1.93 Å) Ni–O bond length. In the ninth Ni3+ site, Ni3+ is bonded to six O2- atoms to form NiO6 octahedra that share a cornercorner with one MgO4 tetrahedra, corners with five NiO4 tetrahedra, edges with three MgO6 octahedra, and edges with three NiO6 octahedra. There are a spread of Ni–O bond distances ranging from 1.91–2.10 Å. In the tenth Ni3+ site, Ni3+ is bonded to four O2- atoms to form NiO4 tetrahedra that share corners with six MgO6 octahedra and corners with six NiO6 octahedra. The corner-sharing octahedra tilt angles range from 56–63°. There are a spread of Ni–O bond distances ranging from 1.90–2.02 Å. In the eleventh Ni3+ site, Ni3+ is bonded to six O2- atoms to form NiO6 octahedra that share corners with three equivalent MgO4 tetrahedra, corners with three equivalent NiO4 tetrahedra, edges with two MgO6 octahedra, and edges with four NiO6 octahedra. There are a spread of Ni–O bond distances ranging from 1.87–1.91 Å. In the twelfth Ni3+ site, Ni3+ is bonded to four O2- atoms to form NiO4 tetrahedra that share corners with three MgO6 octahedra and corners with nine NiO6 octahedra. The corner-sharing octahedra tilt angles range from 49–62°. There is two shorter (1.96 Å) and two longer (1.98 Å) Ni–O bond length. There are twenty-four inequivalent O2- sites. In the first O2- site, O2- is bonded to two Mg2+ and two Ni3+ atoms to form distorted OMg2Ni2 trigonal pyramids that share a cornercorner with one OMg2Ni2 tetrahedra, corners with five OMgNi3 trigonal pyramids, and an edgeedge with one OMg2Ni2 trigonal pyramid. In the second O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to two Mg2+ and two equivalent Ni3+ atoms. In the third O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Mg2+ and three Ni3+ atoms. In the fourth O2- site, O2- is bonded in a rectangular see-saw-like geometry to four Ni3+ atoms. In the fifth O2- site, O2- is bonded to two Mg2+ and two Ni3+ atoms to form a mixture of distorted corner and edge-sharing OMg2Ni2 trigonal pyramids. In the sixth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to one Mg2+ and three Ni3+ atoms. In the seventh O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Mg2+ and three Ni3+ atoms. In the eighth O2- site, O2- is bonded to one Mg2+ and three Ni3+ atoms to form distorted corner-sharing OMgNi3 trigonal pyramids. In the ninth O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Mg2+ and three Ni3+ atoms. In the tenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Mg2+ and two Ni3+ atoms. In the eleventh O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Mg2+ and three Ni3+ atoms. In the twelfth O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Mg2+ and two Ni3+ atoms. In the thirteenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Mg2+ and three Ni3+ atoms. In the fourteenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Mg2+ and three Ni3+ atoms. In the fifteenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Mg2+ and three Ni3+ atoms. In the sixteenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Mg2+ and three Ni3+ atoms. In the seventeenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Mg2+ and two Ni3+ atoms. In the eighteenth O2- site, O2- is bonded to two Mg2+ and two Ni3+ atoms to form a mixture of distorted corner and edge-sharing OMg2Ni2 trigonal pyramids. In the nineteenth O2- site, O2- is bonded to two Mg2+ and two equivalent Ni3+ atoms to form distorted corner-sharing OMg2Ni2 tetrahedra. In the twentieth O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Mg2+ and three Ni3+ atoms. In the twenty-first O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Mg2+ and three Ni3+ atoms. In the twenty-second O2- site, O2- is bonded in a rectangular see-saw-like geometry to four Ni3+ atoms. In the twenty-third O2- site, O2- is bonded to one Mg2+ and three Ni3+ atoms to form distorted OMgNi3 trigonal pyramids that share corners with two equivalent OMg2Ni2 tetrahedra, corners with four OMgNi3 trigonal pyramids, and an edgeedge with one OMgNi3 trigonal pyramid. In the twenty-fourth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to one Mg2+ and three Ni3+ atoms.

二氧合镍酸镁（Mg(NiO₂)₂）具有类尖晶石结构，结晶于单斜晶系（monoclinic）Cm空间群（space group）。该结构为三维框架结构，包含8种不等价的Mg²+位点。
在第一种Mg²+位点中，Mg²+与4个O²-原子配位，形成MgO₄四面体（MgO₄ tetrahedra）；该四面体与3个MgO₆八面体（MgO₆ octahedra）、9个NiO₆八面体（NiO₆ octahedra）通过共顶点（corner-sharing）相连。共顶点八面体的倾斜角（tilt angle）范围为54°~63°，Mg-O键长（bond distance）分布区间为1.96~2.00 Å。
在第二种Mg²+位点中，Mg²+与6个O²-原子配位，形成MgO₆八面体；该八面体与3个MgO₄四面体、3个NiO₄四面体（NiO₄ tetrahedra）通过共顶点相连，同时与6个NiO₆八面体通过共边（edge-sharing）相连。Mg-O键长分布区间为2.03~2.06 Å。
在第三种Mg²+位点中，Mg²+与4个O²-原子配位，形成MgO₄四面体；该四面体与3个MgO₆八面体、9个NiO₆八面体通过共顶点相连。共顶点八面体的倾斜角范围为56°~62°，Mg-O键长分布区间为1.96~2.00 Å。
在第四种Mg²+位点中，Mg²+与6个O²-原子配位，形成MgO₆八面体；该八面体与2个等价的MgO₄四面体、4个NiO₄四面体通过共顶点相连，与1个MgO₆八面体通过共边相连，同时与5个NiO₆八面体通过共边相连。Mg-O键长分布区间为2.02~2.06 Å。
在第五种Mg²+位点中，Mg²+与6个O²-原子配位，形成MgO₆八面体；该八面体与6个NiO₄四面体通过共顶点相连，与2个MgO₆八面体通过共边相连，同时与4个等价的NiO₆八面体通过共边相连。Mg-O键长分布区间为2.03~2.07 Å。
在第六种Mg²+位点中，Mg²+与6个O²-原子配位，形成MgO₆八面体；该八面体与6个NiO₄四面体通过共顶点相连，与2个MgO₆八面体通过共边相连，同时与4个NiO₆八面体通过共边相连。Mg-O键长分布区间为2.04~2.08 Å。
在第七种Mg²+位点中，Mg²+与6个O²-原子配位，形成MgO₆八面体；该八面体与1个MgO₄四面体通过共顶点相连，与5个NiO₄四面体通过共顶点相连，与1个MgO₆八面体通过共边相连，同时与5个NiO₆八面体通过共边相连。Mg-O键长分布区间为2.02~2.07 Å。
在第八种Mg²+位点中，Mg²+与6个O²-原子配位，形成MgO₆八面体；该八面体与6个NiO₄四面体通过共顶点相连，与2个MgO₆八面体通过共边相连，同时与4个NiO₆八面体通过共边相连。Mg-O键长分布区间为2.02~2.07 Å。
该结构包含12种不等价的Ni³+位点。
在第一种Ni³+位点中，Ni³+与6个O²-原子配位，形成NiO₆八面体；该八面体与3个MgO₄四面体、3个NiO₄四面体通过共顶点相连，与2个等价的MgO₆八面体通过共边相连，同时与4个NiO₆八面体通过共边相连。Ni-O键长分布区间为1.90~2.06 Å。
在第二种Ni³+位点中，Ni³+与6个O²-原子配位，形成NiO₆八面体；该八面体与3个等价的MgO₄四面体、3个等价的NiO₄四面体通过共顶点相连，与2个MgO₆八面体通过共边相连，同时与4个NiO₆八面体通过共边相连。Ni-O键长分布区间为1.91~2.06 Å。
在第三种Ni³+位点中，Ni³+与4个O²-原子配位，形成NiO₄四面体；该四面体与6个MgO₆八面体、6个NiO₆八面体通过共顶点相连。共顶点八面体的倾斜角范围为54°~59°，存在2条较短的Ni-O键（键长1.88 Å）与2条较长的Ni-O键（键长1.90 Å）。
在第四种Ni³+位点中，Ni³+与6个O²-原子配位，形成NiO₆八面体；该八面体与2个等价的MgO₄四面体、4个NiO₄四面体通过共顶点相连，与3个MgO₆八面体通过共边相连，同时与3个NiO₆八面体通过共边相连。Ni-O键长分布区间为1.87~2.02 Å。
在第五种Ni³+位点中，Ni³+与4个O²-原子配位，形成NiO₄四面体；该四面体与3个MgO₆八面体、9个NiO₆八面体通过共顶点相连。共顶点八面体的倾斜角范围为55°~61°，Ni-O键长分布区间为1.89~1.94 Å。
在第六种Ni³+位点中，Ni³+与4个O²-原子配位，形成NiO₄四面体；该四面体与6个MgO₆八面体、6个NiO₆八面体通过共顶点相连。共顶点八面体的倾斜角范围为53°~59°，Ni-O键长分布区间为1.83~1.88 Å。
在第七种Ni³+位点中，Ni³+与6个O²-原子配位，形成NiO₆八面体；该八面体与6个NiO₄四面体通过共顶点相连，与2个等价的NiO₆八面体通过共边相连，同时与4个MgO₆八面体通过共边相连。Ni-O键长分布区间为1.87~2.02 Å。
在第八种Ni³+位点中，Ni³+与4个O²-原子配位，形成NiO₄四面体；该四面体与6个MgO₆八面体、6个NiO₆八面体通过共顶点相连。共顶点八面体的倾斜角范围为54°~62°，存在3条较短的Ni-O键（键长1.91 Å）与1条较长的Ni-O键（键长1.93 Å）。
在第九种Ni³+位点中，Ni³+与6个O²-原子配位，形成NiO₆八面体；该八面体与1个MgO₄四面体通过共顶点相连，与5个NiO₄四面体通过共顶点相连，与3个MgO₆八面体通过共边相连，同时与3个NiO₆八面体通过共边相连。Ni-O键长分布区间为1.91~2.10 Å。
在第十种Ni³+位点中，Ni³+与4个O²-原子配位，形成NiO₄四面体；该四面体与6个MgO₆八面体、6个NiO₆八面体通过共顶点相连。共顶点八面体的倾斜角范围为56°~63°，Ni-O键长分布区间为1.90~2.02 Å。
在第十一种Ni³+位点中，Ni³+与6个O²-原子配位，形成NiO₆八面体；该八面体与3个等价的MgO₄四面体、3个等价的NiO₄四面体通过共顶点相连，与2个MgO₆八面体通过共边相连，同时与4个NiO₆八面体通过共边相连。Ni-O键长分布区间为1.87~1.91 Å。
在第十二种Ni³+位点中，Ni³+与4个O²-原子配位，形成NiO₄四面体；该四面体与3个MgO₆八面体、9个NiO₆八面体通过共顶点相连。共顶点八面体的倾斜角范围为49°~62°，存在2条较短的Ni-O键（键长1.96 Å）与2条较长的Ni-O键（键长1.98 Å）。
该结构包含24种不等价的O²-位点。
在第一种O²-位点中，O²-与2个Mg²+及2个Ni³+原子配位，形成畸变的OMg₂Ni₂三角锥（trigonal pyramid）；该三角锥与1个OMg₂Ni₂四面体通过共顶点相连，与5个OMgNi₃三角锥通过共顶点相连，同时与1个OMg₂Ni₂三角锥通过共边相连。
在第二种O²-位点中，O²-采用畸变矩形跷跷板构型，与2个Mg²+及2个等价的Ni³+原子配位。
在第三种O²-位点中，O²-采用矩形跷跷板构型，与1个Mg²+及3个Ni³+原子配位。
在第四种O²-位点中，O²-采用矩形跷跷板构型，与4个Ni³+原子配位。
在第五种O²-位点中，O²-与2个Mg²+及2个Ni³+原子配位，形成兼具畸变共顶点与共边特征的OMg₂Ni₂三角锥。
在第六种O²-位点中，O²-采用畸变矩形跷跷板构型，与1个Mg²+及3个Ni³+原子配位。
在第七种O²-位点中，O²-采用矩形跷跷板构型，与1个Mg²+及3个Ni³+原子配位。
在第八种O²-位点中，O²-与1个Mg²+及3个Ni³+原子配位，形成畸变的共顶点OMgNi₃三角锥。
在第九种O²-位点中，O²-采用矩形跷跷板构型，与1个Mg²+及3个Ni³+原子配位。
在第十种O²-位点中，O²-采用矩形跷跷板构型，与2个Mg²+及2个Ni³+原子配位。
在第十一种O²-位点中，O²-采用矩形跷跷板构型，与1个Mg²+及3个Ni³+原子配位。
在第十二种O²-位点中，O²-采用矩形跷跷板构型，与2个Mg²+及2个Ni³+原子配位。
在第十三种O²-位点中，O²-采用矩形跷跷板构型，与1个Mg²+及3个Ni³+原子配位。
在第十四种O²-位点中，O²-采用矩形跷跷板构型，与1个Mg²+及3个Ni³+原子配位。
在第十五种O²-位点中，O²-采用矩形跷跷板构型，与1个Mg²+及3个Ni³+原子配位。
在第十六种O²-位点中，O²-采用矩形跷跷板构型，与1个Mg²+及3个Ni³+原子配位。
在第十七种O²-位点中，O²-采用矩形跷跷板构型，与2个Mg²+及2个Ni³+原子配位。
在第十八种O²-位点中，O²-与2个Mg²+及2个Ni³+原子配位，形成兼具畸变共顶点与共边特征的OMg₂Ni₂三角锥。
在第十九种O²-位点中，O²-与2个Mg²+及2个等价的Ni³+原子配位，形成畸变的共顶点OMg₂Ni₂四面体。
在第二十种O²-位点中，O²-采用矩形跷跷板构型，与1个Mg²+及3个Ni³+原子配位。
在第二十一种O²-位点中，O²-采用矩形跷跷板构型，与1个Mg²+及3个Ni³+原子配位。
在第二十二种O²-位点中，O²-采用矩形跷跷板构型，与4个Ni³+原子配位。
在第二十三种O²-位点中，O²-与1个Mg²+及3个Ni³+原子配位，形成畸变的OMgNi₃三角锥；该三角锥与2个等价的OMg₂Ni₂四面体通过共顶点相连，与4个OMgNi₃三角锥通过共顶点相连，同时与1个OMgNi₃三角锥通过共边相连。
在第二十四种O²-位点中，O²-采用畸变矩形跷跷板构型，与1个Mg²+及3个Ni³+原子配位。