Materials Data on Ba5Lu8Ni4O21 by Materials Project

Ba5Lu8Ni4O21 crystallizes in the tetragonal I4/m space group. The structure is three-dimensional. there are two inequivalent Ba2+ sites. In the first Ba2+ site, Ba2+ is bonded in a 10-coordinate geometry to ten O2- atoms. There are a spread of Ba–O bond distances ranging from 2.69–3.23 Å. In the second Ba2+ site, Ba2+ is bonded in a distorted q6 geometry to ten O2- atoms. There are two shorter (2.83 Å) and eight longer (2.88 Å) Ba–O bond lengths. There are two inequivalent Lu3+ sites. In the first Lu3+ site, Lu3+ is bonded to seven O2- atoms to form distorted LuO7 pentagonal bipyramids that share corners with three LuO7 pentagonal bipyramids, corners with two equivalent NiO5 trigonal bipyramids, edges with three equivalent LuO7 pentagonal bipyramids, edges with two equivalent NiO5 trigonal bipyramids, and faces with two equivalent LuO7 pentagonal bipyramids. There are a spread of Lu–O bond distances ranging from 2.25–2.39 Å. In the second Lu3+ site, Lu3+ is bonded to seven O2- atoms to form distorted LuO7 pentagonal bipyramids that share corners with two equivalent LuO7 pentagonal bipyramids, corners with two equivalent NiO5 trigonal bipyramids, edges with five LuO7 pentagonal bipyramids, an edgeedge with one NiO5 trigonal bipyramid, and a faceface with one NiO5 trigonal bipyramid. There are a spread of Lu–O bond distances ranging from 2.23–2.37 Å. Ni2+ is bonded to five O2- atoms to form NiO5 trigonal bipyramids that share corners with four LuO7 pentagonal bipyramids, edges with three LuO7 pentagonal bipyramids, and a faceface with one LuO7 pentagonal bipyramid. There are a spread of Ni–O bond distances ranging from 2.01–2.08 Å. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a 6-coordinate geometry to two Ba2+, three Lu3+, and one Ni2+ atom. In the second O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent Ba2+, three Lu3+, and one Ni2+ atom. In the third O2- site, O2- is bonded to two equivalent Ba2+ and four equivalent Lu3+ atoms to form distorted corner-sharing OBa2Lu4 octahedra. The corner-sharing octahedral tilt angles are 0°. In the fourth O2- site, O2- is bonded to four equivalent Ba2+, one Lu3+, and one Ni2+ atom to form a mixture of distorted edge and corner-sharing OBa4LuNi octahedra. The corner-sharing octahedral tilt angles are 4°.

Ba₅Lu₈Ni₄O₂₁结晶于四方晶系I4/m空间群（tetragonal I4/m space group）。结构为三维。存在两种不等价的Ba²⁺位点：第一个Ba²⁺位点中，Ba²⁺以十配位几何（10-coordinate geometry）与十个O²⁻原子成键，Ba–O键长范围为2.69–3.23埃；第二个Ba²⁺位点中，Ba²⁺以扭曲的q6几何结构与十个O²⁻原子成键，存在两条较短的Ba–O键（2.83 Å）和八条较长的Ba–O键（2.88 Å）。

存在两种不等价的Lu³⁺位点：第一个Lu³⁺位点中，Lu³⁺与七个O²⁻原子成键，形成扭曲的LuO₇五角双锥（pentagonal bipyramids）；该五角双锥与三个LuO₇五角双锥共享顶点、与两个等价的NiO₅三角双锥（trigonal bipyramids）共享顶点、与三个等价的LuO₇五角双锥共享边、与两个等价的NiO₅三角双锥共享边、并与两个等价的LuO₇五角双锥共享面，Lu–O键长范围为2.25–2.39埃；第二个Lu³⁺位点中，Lu³⁺与七个O²⁻原子成键，形成扭曲的LuO₇五角双锥；该五角双锥与两个等价的LuO₇五角双锥共享顶点、与两个等价的NiO₅三角双锥共享顶点、与五个LuO₇五角双锥共享边、与一个NiO₅三角双锥共享边、并与一个NiO₅三角双锥共享面。

Ni²⁺与五个O²⁻原子成键，形成NiO₅三角双锥；该三角双锥与四个LuO₇五角双锥共享顶点、与三个LuO₇五角双锥共享边、并与一个LuO₇五角双锥共享面，Ni–O键长范围为2.01–2.08埃。

存在四种不等价的O²⁻位点：第一个O²⁻位点中，O²⁻以六配位几何（6-coordinate geometry）与两个Ba²⁺、三个Lu³⁺和一个Ni²⁺原子成键；第二个O²⁻位点中，O²⁻以四配位几何（4-coordinate geometry）与两个等价的Ba²⁺、三个Lu³⁺和一个Ni²⁺原子成键；第三个O²⁻位点中，O²⁻与两个等价的Ba²⁺和四个等价的Lu³⁺原子成键，形成扭曲的、共享顶点的OBa₂Lu₄八面体（octahedra），共享顶点的八面体倾斜角为0°；第四个O²⁻位点中，O²⁻与四个等价的Ba²⁺、一个Lu³⁺和一个Ni²⁺原子成键，形成扭曲的、共享边与共享顶点混合的OBa₄LuNi八面体，共享顶点的八面体倾斜角为4°。