The new silver(I)thioantimonate(III) [C4N2H14][Ag3Sb3S7] and a new structural variant of the silver(I)thioantimonate(III) [C2N2H9]2[Ag5Sb3S8] both synthesized under solvothermal conditions

The novel silver(I)thioantimonates(III) [C4N2H14][Ag3Sb3S7] (I) (C4N2H12=1,4-diaminobutane) and [C2N2H9]2[Ag5Sb3S8] (II) (C2N2H8=ethylenediamine) were synthesized under solvothermal conditions using AgNO3, Sb, S and the amines as structure directing molecules. Both compounds crystallize as orange needles with lattice parameters a=6.669(1) Å, b=30.440(3) Å, c=9.154(1) Å for I (space group Pnma), and a=6.2712(4) Å, b=15.901(1) Å, c=23.012(2) Å, β=95.37(1)° for II (space group P21/n). In both compounds the primary building units are trigonal SbS3 pyramids, AgS3 triangles and AgS4 tetrahedra. In I the layered [Ag3Sb3S7]2− anion is constructed by two different chains. An [Sb2S4] chain running along [100] is formed by vertex sharing of SbS3 pyramids. The second chain contains a Ag3SbS5 group composed of the AgS4 tetrahedron, two AgS3 units and one SbS3 pyramid. The Ag3SbS5 units are joined via S atoms to form the second chain which is also directed along [100]. The layered anion is then obtained by condensation of the two individual chains. The organic structure director is sandwiched by the inorganic layers and the shortest inter-layer distance is about 6.4 Å. In II the primary building units are linked into different six-membered rings which form a honeycomb-like layer. Two such layers are connected via Ag–S bonds of the AgS4 tetrahedra giving the final undulated double layer anion. The structure directing ethylenediamine cations are located in pairs between the layers and a sandwich-like arrangement of alternating anionic layers and organic cations is observed. The inter-layer separation is about 5.4 Å. Both compounds decompose in a more or less complex manner when heated in an argon atmosphere. The optical band gaps of about 1.9 eV for the two compounds proof the semiconducting behavior. For II the conductivity was measured with impedance spectroscopy and amounts to σ295K=7.6×10−7 Ω−1 cm−1. At 80 °C the conductivity is significantly larger by one order of magnitude.

In the new silver thioantimonate, [C4N2H14][Ag3Sb3S7], the layered [Ag3Sb3S7]2- anion is constructed by two different chains. An [Sb2S4] chain is formed by vertex sharing of SbS3 pyramids. The second chain contains Ag3SbS5 group which are connected by S atoms. The layered anion is obtained by condensation of the two individual chains. The organic structure director is sandwiched by the inorganic layers and the shortest inter-layer distance is about 6.4 Å.Figure optionsDownload as PowerPoint slide