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The title compound was obtained by high temperature solid state reaction and flux method. The crystal belongs to tetragonal system, space group P41, withcell dimensions a= 6. 738(2), c= 24. 532 (3) A, V= 1113. 8(3) A 3, Z= 8, Mr =456. 65, Dc= 5. 45 g/cm3, F(000) = 1632, μ= 189. 3 cm-1. R=0.052, Rw=0. 059.The structure consists of isolated Si2O7 double tetrahedra which are arranged in layersperpendicular to the c axis. Four crystallographically different rare earth atoms in oneunit cell are located on each side of the layers and connect the four nearest SiO4 tetrahedra to form a three-dimensional network structure.
The title compound was obtained by high temperature solid state reaction and flux method. The crystal belongs to tetragonal system, space group P41, with cell dimensions a = 6. 738 (2), c = 24. 532 (3) A, V = 1113 . 8 (3) A 3, Z = 8, Mr = 456.65, Dc = 5.45 g / cm 3, F (000) = 1632, μ = 189. 3 cm -1. R = 0.052, Rw = 0 059.The structure consists of isolated Si2O7 double tetrahedra which are arranged in layersperpendicular to the c axis. Four crystallographically different rare earth atoms in oneunit cell are located on each side of the layers and connect the four nearest SiO4 tetrahedra to form a three- dimensional network structure.