Crystal structure of dicaesium strontium hexa-cyanidoferrate(II), Cs2Sr[Fe(CN)6], from laboratory X-ray powder data

Nicolas Massoni; Mícheál P Moloney; Agnès Grandjean; Scott T Misture; Hans-Conrad Zur Loye

doi:10.1107/S2056989020006660

Crystal structure of dicaesium strontium hexa-cyanidoferrate(II), Cs₂Sr[Fe(CN)₆], from laboratory X-ray powder data

Acta Crystallogr E Crystallogr Commun. 2020 May 22;76(Pt 6):900-904. doi: 10.1107/S2056989020006660. eCollection 2020 Jun 1.

Authors

Nicolas Massoni¹, Mícheál P Moloney¹, Agnès Grandjean¹, Scott T Misture², Hans-Conrad Zur Loye³

Affiliations

¹ CEA, DES, ISEC, DE2D, Univ Montpellier, Marcoule, France.
² Kazuo Inamori School of Engineering, Alfred University, Alfred, NY, 14802, USA.
³ Center for Hierarchical Waste Form Materials, Columbia, SC, 29208, USA.

Abstract

Ferrocyanides with general formula A ^I _xB ^II _y [Fe(CN)₆], where A and B are cations, are thought to accept many substitutions on the A and B positions. In this communication, the synthesis and crystal structure of Cs₂Sr[Fe(CN)₆] are reported. The latter was obtained from K₂Ba[Fe(CN)₆] particles, put in contact with caesium and strontium ions. Hence, a simultaneous ion-exchange mechanism (Cs for K, Sr for Ba) occurs to yield Cs₂Sr[Fe(CN)₆]. The synthesis protocol shows that K₂BaFe(CN)₆ particles can be used for the simultaneous trapping of radioactive caesium and strontium nuclides in water streams. Cs₂Sr[Fe(CN)₆] adopts the cryolite structure type and is isotypic with the known compound Cs₂Na[Mn(CN)₆] [dicaesium sodium hexa-cyanidomanganate(III)]. The octa-hedrally coordinated Sr and Fe sites both are located on inversion centres, and the eightfold-coordinated Cs site on a general position.

Keywords: X-ray powder diffraction; caesium strontium hexaferrocyanate; cryolite-type structure; crystal structure.

Grants and funding

This work was funded by Center for Hierarchical Waste Forms (CHWM) grant . U.S. Department of Energy, Office of Basic Energy Sciences, Division of Materials Sciences and Engineering grant DE-SC0016574.