Synthesis, Structures, and Properties of Layered Quaternary Chalcogenides of the General Formula AlnEQ₄ (A = K, Rb; Ln = Ce, Pr, Eu; E = Si, Ge; Q = S, Se)
Four related quaternary compounds containing rare-earth metals have been synthesized employing the molten flux method and metathesis. the reactions of Eu and Rb2S5 with Si and Ge in evacuated fused silica ampoules at 725 °C for 150 h yielded RbEuSiS4 (I) and RbEuGeS4 (II), respectively. on the other hand, a reaction between CeCl3 and K4Ge4Se10 at 650 °C for 148 h has yielded KCeGeSe4 (III) and KPrSiSe4(IV) was obtained by the reaction of elemental Pr, Si and Se in KCl flux at 850 °C for 168 h. Crystal data for these compounds are as follows: I, orthorhombic, space group P212121 (#19), a = 6.392(1), b = 6.634(2), c = 17.001(3) Å, α = β = γ = 90°, Z = 4; II, monoclinic, space group P21/m (#11), a = 6.498(2), b = 6.689(3), c = 8.964(3) Å, β = 108.647(6)°, Z = 2; III, monoclinic, space group P21 (#4), a = 6.852(2), b = 7.025(2), c = 9.017(3) Å, β = 108.116(2)°, Z = 2; IV, monoclinic, space group P21 (#4), a = 6.736(2), b = 6.943(2), c = 8.990(1) Å, β = 108.262(2)°, Z = 2. the crystal structures of I-IV contain two-dimensional corrugated anionic layers of the general formula, [LnEQ4]− (Ln = Ce, Pr, Eu; E = Si, Ge and Q = S, Se) alternately piled upon layers of alkali cations. in addition to structural elucidation, Raman and UV-visible spectroscopy, and magnetic measurements for compound III (KCeGeSe4) are also discussed.
A. Choudhury et al., "Synthesis, Structures, and Properties of Layered Quaternary Chalcogenides of the General Formula AlnEQ₄ (A = K, Rb; Ln = Ce, Pr, Eu; E = Si, Ge; Q = S, Se)," Journal of Inorganic and General Chemistry, Wiley-VCH Verlag, Jan 2006.
The definitive version is available at http://dx.doi.org/10.1002/zaac.200600226
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