An Investigation of the Crystal Structure of Cd2P2O7 and Cd2V2O7

Abstract

<p>Cd₂P₂O₇ has been found to belong to the space group Γ 1. The structure has a bent P-O(b)-P bond angle for the anion with the central oxygen O(b) close to sp² hybridization. The two PO₄ tetrahedra forming the anion are eclipsed. The cadmium atoms are sixfold co-ordinated to oxygen atoms forming two types of distorted octahedra.</p> <p>Cd₂V₂O₇ belongs to the monoclinic space group C 2/m. As with most structures in the thortveitite series that have been determined, the central oxygen in V₂O₇^4- ion shows enhanced thermal motion. The cadmium atoms are also sixfold co-ordinated to oxygen atoms forming distorted octahedra.</p> <p>The bonding in P₂O₇^4- ion is discussed with reference to values predicted by Cruickshank, and those in the V₂O₇^4- ion compared with values calculated by Barnes and Bachmann.</p>