Europium Oxysulfate Eu2O2SO4 Crystal Structure

Resumo

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) Å, b = 4.1929(4) Å, c = 8.1393(2) Å, 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.