Materials Data on NaAs3H2O9 by Materials Project
NaAs3H2O9 crystallizes in the triclinic P-1 space group. The structure is three-dimensional. Na1+ is bonded to six O2- atoms to form distorted NaO6 octahedra that share corners with two equivalent AsO6 octahedra, corners with five AsO4 tetrahedra, and an edgeedge with one NaO6 octahedra. The corner-sharing octahedra tilt angles range from 46–56°. There are a spread of Na–O bond distances ranging from 2.34–2.68 Å. There are three inequivalent As5+ sites. In the first As5+ site, As5+ is bonded to four O2- atoms to form AsO4 tetrahedra that share corners with two equivalent AsO6 octahedra and corners with three equivalent NaO6 octahedra. The corner-sharing octahedra tilt angles range from 35–60°. There are a spread of As–O bond distances ranging from 1.65–1.77 Å. In the second As5+ site, As5+ is bonded to six O2- atoms to form AsO6 octahedra that share corners with two equivalent NaO6 octahedra, corners with four AsO4 tetrahedra, and an edgeedge with one AsO6 octahedra. The corner-sharing octahedra tilt angles range from 46–56°. There are a spread of As–O bond distances ranging from 1.85–1.88 Å. In the third As5+ site, As5+ is bonded to four O2- atoms to form AsO4 tetrahedra that share corners with two equivalent NaO6 octahedra and corners with two equivalent AsO6 octahedra. The corner-sharing octahedra tilt angles range from 50–63°. There are a spread of As–O bond distances ranging from 1.67–1.76 Å. There are two inequivalent H1+ sites. In the first H1+ site, H1+ is bonded in a linear geometry to two O2- atoms. There is one shorter (1.04 Å) and one longer (1.54 Å) H–O bond length. 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. There are nine inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted trigonal planar geometry to two equivalent Na1+ and one As5+ atom. In the second O2- site, O2- is bonded in a 2-coordinate geometry to one Na1+, one As5+, and one H1+ atom. In the third O2- site, O2- is bonded in a distorted trigonal planar geometry to one Na1+, one As5+, and one H1+ atom. In the fourth O2- site, O2- is bonded in a bent 120 degrees geometry to two As5+ atoms. In the fifth O2- site, O2- is bonded in a distorted trigonal planar geometry to one Na1+ and two equivalent As5+ atoms. In the sixth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to two As5+ atoms. In the seventh O2- site, O2- is bonded in a 3-coordinate geometry to one Na1+, one As5+, and one H1+ atom. In the eighth O2- site, O2- is bonded in a bent 120 degrees geometry to two As5+ atoms. In the ninth O2- site, O2- is bonded in a bent 120 degrees geometry to two As5+ atoms.