Europium Oxysulfate Eu2O2SO4 Crystal Structure

The europium oxysulfate crystal structure was solved by X-ray powder diffraction. The compound crystallizes in monoclinic crystal system. The unit cell parameters are a = 13.6952(1) A, b = 4.1929(4) A, c = 8.1393(2) A, β = 107.455(4)°, space group C2/c. The three major structural elements are recognized to be Eu atoms, SO4 tetrahedra, and μ-O atoms, and their coordination environments were analyzed. The specific structural elements are infinite screw chains composed of trigonal prisms [EuO9]; sulfate tetrahedra [(SO4)Eu8] enclosed into cubes built of europium atoms; and infinite chains composed of tetrahedra [OEu4]. Rationale was given to the splitting of the IR absorption bands corresponding to the vibrations of sulfate groups.