IUCr journals

Pseudo-merohedrally twinned praseodymium hexacyanoferrate(III) tetrahydrate

Acta Cryst. (2004). C60, i104–i106 [doi:10.1107/S010827010402092X]

[crystal structure] The structure of Pr[Fe(CN)6]·4H2O viewed along the a axis. FeC6 octahedra are shown in blue color.
The article describes the structure of the title compound, diaquahexa-μ-cyano-ferrate(III)praseodymium(III) dihydrate, Pr[Fe(CN)6]·4H2O or [PrFe(CN)6(H2O)2]·2H2O. The crystals, although orthorhombic, space group Cmcm, are pseudo-merohedrally twinned with three components, simulating thus the hexagonal system. The Pr atom is coordinated by eight atoms, viz. six N and two symmetry-related water O atoms. The Pr polyhedron is linked to an FeC6 octahedron through N atoms, forming an infinite array. The second (symmetry independent) water molecule is not included in coordination and is weakly hydrogen bonded to N atoms.

V. Langer, L Smrcok and Y. Masuda