Materials Data on As2O9 by Materials Project
As2O7O2 crystallizes in the monoclinic P2_1/c space group. The structure is one-dimensional and consists of four oxygen molecules and two As2O7 ribbons oriented in the (0, 0, 1) direction. In each As2O7 ribbon, there are two inequivalent As sites. In the first As site, As is bonded in a distorted trigonal pyramidal geometry to four O atoms. There are a spread of As–O bond distances ranging from 1.65–2.09 Å. In the second As site, As is bonded in a trigonal non-coplanar geometry to three O atoms. There are a spread of As–O bond distances ranging from 1.65–2.12 Å. There are seven inequivalent O sites. In the first O site, O is bonded in a bent 120 degrees geometry to one As and one O atom. The O–O bond length is 1.37 Å. In the second O site, O is bonded in a single-bond geometry to one As atom. In the third O site, O is bonded in a single-bond geometry to one As atom. In the fourth O site, O is bonded in a bent 120 degrees geometry to one As and one O atom. In the fifth O site, O is bonded in a bent 120 degrees geometry to one As and one O atom. The O–O bond length is 1.32 Å. In the sixth O site, O is bonded in a bent 120 degrees geometry to one As and one O atom. In the seventh O site, O is bonded in a single-bond geometry to one As atom.