RbFe(HPO4)2: an iron(III) phosphate with an intersecting tunnel structure

Abstract

A new iron(III) phosphate, RbFe(HPO₄)₂, has been synthesised hydrothermally at 230°C and characterized by single-crystal X-ray diffraction. The crystal is trigonal with a very long c axis: space group Rc, a= 8.160(1), c= 52.75(1)Å, Z= 18 and R= 0.0207. The compound adopts an intersecting tunnel structure, with the rubidium cations in the tunnels. The framework consists of corner-sharing FeO₆ octahedra and HPO₄ groups. A triclinic polymorph was also obtained.