Materials Data on Na2Te2H4O7 by Materials Project

Na2H4Te2O7 crystallizes in the triclinic P-1 space group. The structure is three-dimensional. there are two inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded to five O2- atoms to form edge-sharing NaO5 trigonal bipyramids. There are a spread of Na–O bond distances ranging from 2.40–2.46 Å. In the second Na1+ site, Na1+ is bonded to six O2- atoms to form distorted edge-sharing NaO6 octahedra. There are a spread of Na–O bond distances ranging from 2.37–2.61 Å. There are four inequivalent H1+ sites. In the first H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 1.00 Å. In the second H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 1.00 Å. In the third H1+ site, H1+ is bonded in a single-bond geometry to two O2- atoms. There is one shorter (1.00 Å) and one longer (1.75 Å) H–O bond length. In the fourth H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.99 Å. There are two inequivalent Te4+ sites. In the first Te4+ site, Te4+ is bonded in a distorted see-saw-like geometry to four O2- atoms. There are a spread of Te–O bond distances ranging from 1.88–2.50 Å. In the second Te4+ site, Te4+ is bonded in a distorted see-saw-like geometry to four O2- atoms. There are a spread of Te–O bond distances ranging from 1.87–2.17 Å. There are seven inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to two equivalent Na1+ and two equivalent Te4+ atoms. In the second O2- site, O2- is bonded to two equivalent Na1+ and two equivalent Te4+ atoms to form distorted edge-sharing ONa2Te2 tetrahedra. In the third O2- site, O2- is bonded in a distorted trigonal planar geometry to one Na1+ and two Te4+ atoms. In the fourth O2- site, O2- is bonded in a 2-coordinate geometry to one Na1+, one H1+, and one Te4+ atom. In the fifth O2- site, O2- is bonded in a distorted water-like geometry to one Na1+ and one Te4+ atom. In the sixth O2- site, O2- is bonded in a distorted water-like geometry to two equivalent Na1+ and two H1+ atoms. In the seventh O2- site, O2- is bonded in a distorted water-like geometry to two equivalent Na1+ and two H1+ atoms.

Na₂H₄Te₂O₇ 晶体属于三斜晶系P-1空间群（triclinic P-1 space group），其结构为三维骨架。存在两个不等价的钠离子（Na1+）位点。在第一个Na1+位点中，钠离子与五个氧离子（O2-）配位，形成共边NaO₅三角双锥（trigonal bipyramids）结构，Na-O键的键长分布范围为2.40~2.46 Å。在第二个Na1+位点中，钠离子与六个O2-配位，形成畸变共边NaO₆八面体（octahedra）结构，Na-O键的键长分布范围为2.37~2.61 Å。
存在四个不等价的氢离子（H1+）位点。在第一个H1+位点中，氢离子以单键配位几何与一个O2-结合，H-O键长为1.00 Å。在第二个H1+位点中，氢离子以单键配位几何与一个O2-结合，H-O键长为1.00 Å。在第三个H1+位点中，氢离子以单键配位几何与两个O2-结合，存在一条较短（1.00 Å）和一条较长（1.75 Å）的H-O键。在第四个H1+位点中，氢离子以单键配位几何与一个O2-结合，H-O键长为0.99 Å。
存在两个不等价的碲离子（Te4+）位点。在第一个Te4+位点中，碲离子以畸变跷跷板型配位几何（see-saw-like geometry）与四个O2-配位，Te-O键的键长分布范围为1.88~2.50 Å。在第二个Te4+位点中，碲离子以畸变跷跷板型配位几何与四个O2-配位，Te-O键的键长分布范围为1.87~2.17 Å。
存在七个不等价的氧离子（O2-）位点。在第一个O2-位点中，氧离子以畸变矩形跷跷板型配位几何与两个等价的Na1+和两个等价的Te4+结合。在第二个O2-位点中，氧离子与两个等价的Na1+和两个等价的Te4+结合，形成畸变共边ONa₂Te₂四面体结构。在第三个O2-位点中，氧离子以畸变三角平面配位几何与一个Na1+和两个Te4+结合。在第四个O2-位点中，氧离子以二配位几何与一个Na1+、一个H1+和一个Te4+结合。在第五个O2-位点中，氧离子以畸变类水配位几何与一个Na1+和一个Te4+结合。在第六个O2-位点中，氧离子以畸变类水配位几何与两个等价的Na1+和两个等价的H1+结合。在第七个O2-位点中，氧离子以畸变类水配位几何与两个等价的Na1+和两个等价的H1+结合。