Crystal structure of Zn2(HTeO3)(AsO4)

Abstract

Single crystals of Zn₂(HTeO₃)(AsO₄), dizinc(II) hydroxidodioxidotellurate(IV) oxidoarsenate(V), were obtained as one of the by-products in a hydro-thermal reaction between Zn(NO₃)₂·6H₂O, TeO₂, H₃AsO₄ and NH₃ in molar ratios of 2:1:2:10 at 483 K for seven days. The asymmetric unit of Zn₂(HTeO₃)(AsO₄) contains one Te (site symmetry m), one As (m), one Zn (1), five O (three m, two 1) and one H (m) site. The Zn^II atom exhibits a coordination number of 5 and is coordinated by four oxygen atoms and a hydroxide group, forming a distorted trigonal bipyramid. The hydroxide ion is positioned at a significantly larger distance on one of the axial positions of the bipyramid. The [ZnO₄OH] polyhedra are connected to each other by corner-sharing to form _∞ ²[ZnO_3/2(OH)_1/2O_1/1] layers extending parallel to (001). The Te^IV atom is coordinated by three oxygen atoms and a hydroxide group in a one-sided manner in the shape of a bis-phenoid, revealing stereochemical activity of its 5s ² electron lone pair. The As^V atom is coordinated by four oxygen atoms to form the tetra-hedral oxidoarsenate(V) anion. By corner-sharing, [TeO₃OH] and [AsO₄] groups link adjacent _∞ ²[ZnO_3/2(OH)_1/2O_1/1] layers along [001] into a three-dimensional framework structure.

Keywords: crystal structure; hydrogen bonding; lone pair electrons; oxidoarsenate(V); oxidotellurate(IV); stereochemical activity.