Reinvestigation of structural and magnetic properties of a cyano-bridged bimetallic compound: K2Mn3(H2O)6[ Mo(CN)7]2. 6H2O

In this communication, we reinvestigate the structural and magnetic properties of the title compound K 2 Mn 3 (H 2 O) 6 [Mo(CN) 7 ] 2 -6H 2 O. We show that this material crystallises in the space group C2/c (monoclinic no.15), instead of C2 (monoclinic no.5) reported by J. Larianova et al. in J. Am. Chem. Soc., 121 (1999) 3349 - 3356. The C2/c and C2 unit cells are closely related. The presence of an inversion center in the C2/c unit cell implies the doubling of the c parameter in comparison to the C2 unit cell. Magnetic measurements show a transition from a paramagnetic state to a ferrimagnetic ordered state at 39 K, in agreement to neutron diffraction experiments.