Cs₃Fe₅O(OH)(AsO₄)₅: A novel iron(III) arsenate containing four-, five- and six-coordinated iron atoms

A novel iron(III) arsenate is synthesized under hydrothermal conditions and characterized by single-crystal X-ray diffraction, which reveals a framework structure of vertex- and edge-sharing Fe-O polyhedra crosslinked by vertex-sharing AsO₄ tetrahedra in a manner that generates tunnels and cavities occupied by Cs⁺ cations.