STRUCTURE OF K3NA4H2[SMW10O36].22H2O

Tripotassium tetrasodium dihydrogen decatungstosamarate docosahydrate, K3Na4H2[SmW10O36].22H2O, consists of a decatungstosamarate anion, three sevenfold or eightfold coordinated potassium cations, four octahedrally coordinated sodium cations, and water molecules. The decatungstosamarate anion is comprised of two W5O186- moieties chelating to a central Sm3+ cation, which lies in a tetragonal antiprismatic coordination field. The Sm atom is not at the midpoint of the two W5O186- groups. The Sm-W distances are 3.820-3.840 angstrom for the W atoms in one group and 3.855-3.888 angstrom for those in the other.