Materials Data on Na2SeO9 by Materials Project

Na2SeO9 crystallizes in the tetragonal P4_322 space group. The structure is three-dimensional. there are two inequivalent Na sites. In the first Na site, Na is bonded in a 8-coordinate geometry to eight O atoms. There are a spread of Na–O bond distances ranging from 2.42–2.98 Å. In the second Na site, Na is bonded in a see-saw-like geometry to four O atoms. There are two shorter (2.40 Å) and two longer (2.44 Å) Na–O bond lengths. Se is bonded in a water-like geometry to four O atoms. There are two shorter (1.68 Å) and two longer (2.58 Å) Se–O bond lengths. There are five inequivalent O sites. In the first O site, O is bonded in a 3-coordinate geometry to two Na and one O atom. The O–O bond length is 1.37 Å. In the second O site, O is bonded in a distorted bent 120 degrees geometry to one Na and one O atom. The O–O bond length is 1.26 Å. In the third O site, O is bonded in a rectangular see-saw-like geometry to two equivalent Na and two equivalent O atoms. In the fourth O site, O is bonded in a distorted water-like geometry to one Se and one O atom. In the fifth O site, O is bonded in a distorted trigonal non-coplanar geometry to two Na and one Se atom.