The structure of two manganese hexacyanometallates(II): Mn2[Fe(CN)6].8H2O and Mn2[Os(CN)6].8H2O

The crystal structures of two manganese hexacyanometallates(II), Mn 2 [Fe(CN) 6 ].8H 2 O and Mn 2 [Os(CN) 6 ].8H 2 O, were refined from X-ray powder diffraction data using the Rietveld method, with the reported structure for Mn 2 [Ru(CN) 6 ].8H 2 O used as a structural model. These compounds are isomorphous and crystallize in the monoclinic space group P 2 1 / n . Their crystallization water is not firmly bound and can be removed without disrupting the M–C≡N–Mn network. In the dehydrated complexes, the outer cation (Mn) remains linked to only three N atoms from CN ligands while the inner cation (Fe,Os) preserves its coordination sphere. The IR, Raman, and Mössbauer spectra for the hydrated and anhydrous forms are explained based on the refined structures.