DOE OSTI2020
Na2Be(GeO3)2 crystallizes in the orthorhombic Fdd2 space group. The structure is three-dimensional. there are four inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Na–O bond distances ranging from 2.30–2.77 Å. In the second Na1+ site, Na1+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Na–O bond distances ranging from 2.51–2.91 Å. In the third Na1+ site, Na1+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Na–O bond distances ranging from 2.32–2.90 Å. In the fourth Na1+ site, Na1+ is bonded to five O2- atoms to form distorted NaO5 trigonal bipyramids that share corners with two equivalent BeO4 tetrahedra, corners with six GeO4 tetrahedra, and an edgeedge with one BeO4 tetrahedra. There are a spread of Na–O bond distances ranging from 2.31–2.48 Å. There are two inequivalent Be2+ sites. In the first Be2+ site, Be2+ is bonded to four O2- atoms to form BeO4 tetrahedra that share corners with four GeO4 tetrahedra and corners with two equivalent NaO5 trigonal bipyramids. There are a spread of Be–O bond distances ranging from 1.64–1.68 Å. In the second Be2+ site, Be2+ is bonded to four O2- atoms to form BeO4 tetrahedra that share corners with four GeO4 tetrahedra and edges with two equivalent NaO5 trigonal bipyramids. There is two shorter (1.65 Å) and two longer (1.66 Å) Be–O bond length. There are four inequivalent Ge4+ sites. In the first Ge4+ site, Ge4+ is bonded to four O2- atoms to form GeO4 tetrahedra that share corners with two equivalent BeO4 tetrahedra, corners with two equivalent GeO4 tetrahedra, and corners with two equivalent NaO5 trigonal bipyramids. There is two shorter (1.74 Å) and two longer (1.81 Å) Ge–O bond length. In the second Ge4+ site, Ge4+ is bonded to four O2- atoms to form GeO4 tetrahedra that share corners with two equivalent BeO4 tetrahedra, corners with two equivalent GeO4 tetrahedra, and corners with two equivalent NaO5 trigonal bipyramids. There is two shorter (1.74 Å) and two longer (1.82 Å) Ge–O bond length. In the third Ge4+ site, Ge4+ is bonded to four O2- atoms to form GeO4 tetrahedra that share corners with two BeO4 tetrahedra, corners with two GeO4 tetrahedra, and corners with two equivalent NaO5 trigonal bipyramids. There are a spread of Ge–O bond distances ranging from 1.73–1.81 Å. In the fourth Ge4+ site, Ge4+ is bonded to four O2- atoms to form GeO4 tetrahedra that share corners with two BeO4 tetrahedra, corners with two GeO4 tetrahedra, and corners with two equivalent NaO5 trigonal bipyramids. There are a spread of Ge–O bond distances ranging from 1.74–1.83 Å. There are nine inequivalent O2- sites. In the first O2- site, O2- is bonded in a 3-coordinate geometry to two Na1+ and two Ge4+ atoms. In the second O2- site, O2- is bonded in a 3-coordinate geometry to two Na1+ and two Ge4+ atoms. In the third O2- site, O2- is bonded in a 4-coordinate geometry to two Na1+, one Be2+, and one Ge4+ atom. In the fourth O2- site, O2- is bonded in a 3-coordinate geometry to two Na1+, one Be2+, and one Ge4+ atom. In the fifth O2- site, O2- is bonded in a 4-coordinate geometry to two Na1+, one Be2+, and one Ge4+ atom. In the sixth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to two Na1+, one Be2+, and one Ge4+ atom. In the seventh O2- site, O2- is bonded to two Na1+ and two Ge4+ atoms to form distorted corner-sharing ONa2Ge2 tetrahedra. In the eighth O2- site, O2- is bonded in a 4-coordinate geometry to two Na1+, one Be2+, and one Ge4+ atom. In the ninth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to two Na1+, one Be2+, and one Ge4+ atom.