title: Di-mu-oxido-bis{bis[N,N'-bis(2-pyridylmethyl)ethane-1,2-diamine]manganese(III,IV)} tris(perchlorate) hexahydrate: clarification of an order-disorder phase transition.
abstract: The title compound, [Mn(2)O(2)(C(14)H(18)N(4))(2)](ClO(4))(3).6H(2)O, contains a mixed-valent Mn(III)/Mn(IV) complex. In accordance with a previous report [Collins, Hodgson, Michelsen & Towle (1987). J. Chem. Soc. Chem. Commun. pp. 1659-1660], the structure at 295 K is best described in the space group C2/c, with the complex exhibiting twofold rotational symmetry, and with half site occupancy for one perchlorate anion and several solvent water molecules. At 180 K, the structure is ordered in the subgroup P2(1)/n and is clearly shown to be a hexahydrate, rather than the previously reported trihydrate. The origin of the order-disorder phase transition lies in the thermal motion of the perchlorate anions.
authors.affiliation: Department of Physics and Chemistry, University of Southern Denmark, Campusvej 55, 5230 Odense, Denmark.
authors.forename: Anne
authors.initials: A
authors.lastname: Nielsen
authors.forename: Christine J
authors.initials: CJ
authors.lastname: McKenzie
authors.forename: Andrew D
authors.initials: AD
authors.lastname: Bond