RESUMEN
Two types of lanthanide selenidostannates(iv) [Ln2(tepa)2(µ-OH)2Sn2Se6] {Ln = Y(), Pr (), Dy (), Er (), Tm (); tepa = tetraethylenepentamine} and [Ln2(tepa)2(µ2-OH)2Cl2]2[Sn4Se10]·4H2O {Ln = Y (), Dy (), Er (), Tm ()} have been synthesized under identical solvothermal conditions and characterized structurally. Type I (, , , and ) displays 1-D neutral chains [Ln2(tepa)2(µ-OH)2Sn2Se6]n, while type II (, , and ) contains discrete adamantane-like [Sn4Se10](4-) ions with binuclear lanthanide complex [Ln2(tepa)2(µ-OH)2Cl2](2+) ions as counterions. Although the solvothermal synthetic methods could result in the formation of various transition-metal chalcogenidometalates, such identical experimental conditions usually result in the only stable phases of lanthanide chalcogenidometalates. Hence, two different lanthanide selenidostannates(iv), obtained under same solvothermal conditions and starting materials, have been first observed in this work. The optical properties of all the compounds have been investigated by UV-vis spectra.