Materials Data on Pr8Ni4O17 by Materials Project

Pr8Ni4O17 crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are eight inequivalent Pr3+ sites. In the first Pr3+ site, Pr3+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Pr–O bond distances ranging from 2.24–2.73 Å. In the second Pr3+ site, Pr3+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Pr–O bond distances ranging from 2.33–2.67 Å. In the third Pr3+ site, Pr3+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Pr–O bond distances ranging from 2.36–2.67 Å. In the fourth Pr3+ site, Pr3+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Pr–O bond distances ranging from 2.28–3.01 Å. In the fifth Pr3+ site, Pr3+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Pr–O bond distances ranging from 2.27–2.81 Å. In the sixth Pr3+ site, Pr3+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Pr–O bond distances ranging from 2.26–2.56 Å. In the seventh Pr3+ site, Pr3+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Pr–O bond distances ranging from 2.29–2.86 Å. In the eighth Pr3+ site, Pr3+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Pr–O bond distances ranging from 2.39–2.74 Å. There are four inequivalent Ni+2.50+ sites. In the first Ni+2.50+ site, Ni+2.50+ is bonded to six O2- atoms to form corner-sharing NiO6 octahedra. There are a spread of Ni–O bond distances ranging from 2.02–2.56 Å. In the second Ni+2.50+ site, Ni+2.50+ is bonded to six O2- atoms to form corner-sharing NiO6 octahedra. There are a spread of Ni–O bond distances ranging from 1.99–2.26 Å. In the third Ni+2.50+ site, Ni+2.50+ is bonded to five O2- atoms to form distorted corner-sharing NiO5 square pyramids. The corner-sharing octahedra tilt angles range from 7–33°. There are a spread of Ni–O bond distances ranging from 1.94–2.46 Å. In the fourth Ni+2.50+ site, Ni+2.50+ is bonded to five O2- atoms to form corner-sharing NiO5 trigonal bipyramids. The corner-sharing octahedra tilt angles range from 7–31°. There are a spread of Ni–O bond distances ranging from 1.92–2.15 Å. There are seventeen inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to three Pr3+ and one Ni+2.50+ atom. In the second O2- site, O2- is bonded to three Pr3+ and two Ni+2.50+ atoms to form OPr3Ni2 trigonal bipyramids that share a cornercorner with one OPr4 tetrahedra, corners with four equivalent OPr3Ni2 trigonal bipyramids, and a cornercorner with one OPr4 trigonal pyramid. In the third O2- site, O2- is bonded in a 1-coordinate geometry to four Pr3+ and two Ni+2.50+ atoms. In the fourth O2- site, O2- is bonded in a distorted see-saw-like geometry to two Pr3+ and two Ni+2.50+ atoms. In the fifth O2- site, O2- is bonded in a 6-coordinate geometry to four Pr3+ and two Ni+2.50+ atoms. In the sixth O2- site, O2- is bonded to four Pr3+ atoms to form OPr4 tetrahedra that share corners with three OPr3Ni2 trigonal bipyramids and edges with two equivalent OPr4 trigonal pyramids. In the seventh O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to three Pr3+ and one Ni+2.50+ atom. In the eighth O2- site, O2- is bonded in a 4-coordinate geometry to three Pr3+ and one Ni+2.50+ atom. In the ninth O2- site, O2- is bonded in a distorted trigonal planar geometry to three Pr3+ atoms. In the tenth O2- site, O2- is bonded to four Pr3+ atoms to form distorted OPr4 trigonal pyramids that share corners with three OPr3Ni2 trigonal bipyramids and edges with two equivalent OPr4 tetrahedra. In the eleventh O2- site, O2- is bonded to three Pr3+ and two Ni+2.50+ atoms to form distorted OPr3Ni2 trigonal bipyramids that share a cornercorner with one OPr4 tetrahedra, corners with four equivalent OPr3Ni2 trigonal bipyramids, and a cornercorner with one OPr4 trigonal pyramid. In the twelfth O2- site, O2- is bonded to two Pr3+ and two Ni+2.50+ atoms to form distorted edge-sharing OPr2Ni2 trigonal pyramids. In the thirteenth O2- site, O2- is bonded to three Pr3+ and two Ni+2.50+ atoms to form distorted OPr3Ni2 trigonal bipyramids that share a cornercorner with one OPr4 tetrahedra, a cornercorner with one OPr4 trigonal pyramid, and edges with two equivalent OPr2Ni2 trigonal pyramids. In the fourteenth O2- site, O2- is bonded in a 6-coordinate geometry to four Pr3+ and two Ni+2.50+ atoms. In the fifteenth O2- site, O2- is bonded in a 4-coordinate geometry to three Pr3+ and one Ni+2.50+ atom. In the sixteenth O2- site, O2- is bonded in a distorted see-saw-like geometry to three Pr3+ and one Ni+2.50+ atom. In the seventeenth O2- site, O2- is bonded in a 4-coordinate geometry to three Pr3+ and one Ni+2.50+ atom.

Pr₈Ni₄O₁₇ 结晶于三斜晶系P1空间群（triclinic P1 space group），其结构为三维骨架结构。存在8种不等价的镨离子（Pr³⁺）位点。
在第一个Pr³⁺位点中，Pr³⁺以六配位几何与6个氧离子（O²⁻）成键，Pr-O键长分布范围为2.24~2.73 Å。
在第二个Pr³⁺位点中，Pr³⁺以七配位几何与7个O²⁻成键，Pr-O键长分布范围为2.33~2.67 Å。
在第三个Pr³⁺位点中，Pr³⁺以七配位几何与7个O²⁻成键，Pr-O键长分布范围为2.36~2.67 Å。
在第四个Pr³⁺位点中，Pr³⁺以七配位几何与7个O²⁻成键，Pr-O键长分布范围为2.28~3.01 Å。
在第五个Pr³⁺位点中，Pr³⁺以七配位几何与7个O²⁻成键，Pr-O键长分布范围为2.27~2.81 Å。
在第六个Pr³⁺位点中，Pr³⁺以六配位几何与6个O²⁻成键，Pr-O键长分布范围为2.26~2.56 Å。
在第七个Pr³⁺位点中，Pr³⁺以七配位几何与7个O²⁻成键，Pr-O键长分布范围为2.29~2.86 Å。
在第八个Pr³⁺位点中，Pr³⁺以七配位几何与7个O²⁻成键，Pr-O键长分布范围为2.39~2.74 Å。

存在4种不等价的平均价态为+2.5的镍离子（Ni².50+）位点。
在第一个Ni².50+位点中，Ni².50+与6个O²⁻成键，形成共角连接的NiO₆八面体（corner-sharing NiO6 octahedra），Ni-O键长分布范围为2.02~2.56 Å。
在第二个Ni².50+位点中，Ni².50+与6个O²⁻成键，形成共角连接的NiO₆八面体，Ni-O键长分布范围为1.99~2.26 Å。
在第三个Ni².50+位点中，Ni².50+与5个O²⁻成键，形成畸变的共角连接NiO₅四方锥（distorted corner-sharing NiO5 square pyramids），共角八面体的倾斜角度范围为7°~33°，Ni-O键长分布范围为1.94~2.46 Å。
在第四个Ni².50+位点中，Ni².50+与5个O²⁻成键，形成共角连接的NiO₅三角双锥（corner-sharing NiO5 trigonal bipyramids），共角八面体的倾斜角度范围为7°~31°，Ni-O键长分布范围为1.92~2.15 Å。

存在17种不等价的O²⁻位点。
在第一个O²⁻位点中，O²⁻以畸变矩形跷跷板状几何与3个Pr³⁺和1个Ni².50+成键。
在第二个O²⁻位点中，O²⁻与3个Pr³⁺和2个Ni².50+成键，形成OPr₃Ni₂三角双锥结构，该结构与1个OPr₄四面体共享1个顶角，与4个等价的OPr₃Ni₂三角双锥共享多个顶角，并与1个OPr₄三角锥共享1个顶角。
在第三个O²⁻位点中，O²⁻以单配位几何与4个Pr³⁺和2个Ni².50+成键。
在第四个O²⁻位点中，O²⁻以畸变跷跷板状几何与2个Pr³⁺和2个Ni².50+成键。
在第五个O²⁻位点中，O²⁻以六配位几何与4个Pr³⁺和2个Ni².50+成键。
在第六个O²⁻位点中，O²⁻与4个Pr³⁺成键，形成OPr₄四面体结构，该结构与3个OPr₃Ni₂三角双锥共享顶角，并与2个等价的OPr₄三角锥共享边。
在第七个O²⁻位点中，O²⁻以畸变矩形跷跷板状几何与3个Pr³⁺和1个Ni².50+成键。
在第八个O²⁻位点中，O²⁻以四配位几何与3个Pr³⁺和1个Ni².50+成键。
在第九个O²⁻位点中，O²⁻以畸变三角平面几何与3个Pr³⁺成键。
在第十个O²⁻位点中，O²⁻与4个Pr³⁺成键，形成畸变的OPr₄三角锥结构，该结构与3个OPr₃Ni₂三角双锥共享顶角，并与2个等价的OPr₄四面体共享边。
在第十一个O²⁻位点中，O²⁻与3个Pr³⁺和2个Ni².50+成键，形成畸变的OPr₃Ni₂三角双锥结构，该结构与1个OPr₄四面体共享1个顶角，与4个等价的OPr₃Ni₂三角双锥共享多个顶角，并与1个OPr₄三角锥共享1个顶角。
在第十二个O²⁻位点中，O²⁻与2个Pr³⁺和2个Ni².50+成键，形成畸变的共边连接OPr₂Ni₂三角锥结构（distorted edge-sharing OPr2Ni2 trigonal pyramids）。
在第十三个O²⁻位点中，O²⁻与3个Pr³⁺和2个Ni².50+成键，形成畸变的OPr₃Ni₂三角双锥结构，该结构与1个OPr₄四面体共享1个顶角，与1个OPr₄三角锥共享1个顶角，并与2个等价的OPr₂Ni₂三角锥共享边。
在第十四个O²⁻位点中，O²⁻以六配位几何与4个Pr³⁺和2个Ni².50+成键。
在第十五个O²⁻位点中，O²⁻以四配位几何与3个Pr³⁺和1个Ni².50+成键。
在第十六个O²⁻位点中，O²⁻以畸变跷跷板状几何与3个Pr³⁺和1个Ni².50+成键。
在第十七个O²⁻位点中，O²⁻以四配位几何与3个Pr³⁺和1个Ni².50+成键。