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

• Main Authors: Nicolas Massoni, Mícheál P. Moloney, Agnès Grandjean, Scott T. Misture, Hans-Conrad zur Loye
• Format: Article
• Language: English
• Published: International Union of Crystallography 2020-06-01
• Series: Acta Crystallographica Section E: Crystallographic Communications
• Subjects: crystal structure; x-ray powder diffraction; caesium strontium hexaferrocyanate; cryolite-type structure
• Online Access: http://scripts.iucr.org/cgi-bin/paper?S2056989020006660

Ferrocyanides with general formula AIxBIIy[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 hexacyanidomanganate(III)]. The octahedrally coordinated Sr and Fe sites both are located on inversion centres, and the eightfold-coordinated Cs site on a general position.