High-temperature phase of trans-tetraaquabis(trifluoroacetato-O)-manganese(II)

The title compound, [Mn(CF3COO)(2)(H2O)(4)], crystallizes in the monoclinic space group C2/c. At about 215 K, it undergoes a reversible phase transiti on, which leads to crystal twinning. The crystal structure of the high-temp erature phase was determined at 220 K. The Mn2+ ion lies on a twofold axis and is octahedrally coordinated by two monodentate trifluoroacetate ligands in apical positions and by four equatorial aqua ligands, two of which lie on the twofold axis. Hydrogen-bonding interactions connect the complex mole cules, generating a three-dimensional network.