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Martinez-Garcia et al. proposed that in the studied Mn2M hydrates in Mn2[M(CN)6].xH2O (where x = 8 and 2 and M = Fe, Ru, Os) the antiferromagnetic interaction between the Mn atoms through the aquo bridges is particularly weak, which was attributed to bonding properties of the water molecule, particularly to its low ability to allow a significant contribution from the metallic electron cloud to the coordination bond. Because the coordination site is always the outer metal, in this case, the manganese atom, with a relatively low polarizing power . When the water bridges are removed a structural transformation takes place and the Mn atoms become bridged through bifurcated N ends. The bond formed between the meta and the CN group at the N end shows an increased covalence (a highly covalent metal-ligand bond formed) as detected by the stronger antiferromagnetic interaction between adjacent Mn atoms, but also by the IR and Mossbauer data.
 R Martinez-Garcia, L Reguera, M. Knobel and E Reguera, J. Phys.:Condens. Matter 19 (2007) 056202 (11pp)
 Zhang Y, Inorg. Chem. 21,1982, 3886