Novel sandwiched intermetallic selenoantimonates:: Soft synthesis and characterization of Cu2SbSe3•0.5en and Cu2SbSe3•en

Two novel two-dimensional (layered) intermetallic copper selenoantimonates Cu2SbSe3. 0.5en (I) and Cu2SbSe3. en (II), have been prepared by soft solvothermal reactions of CuCl, SbCl3, and Se with A(2)Se (A = Na, K) in the presence of ethylenediamine. Single-crystal X-ray diffraction analyses show that both structures crystallize in the monoclinic crystal system. Compound I belongs to the P2(1)/n (no. 14) space group with a = 6.399(1) Angstrom, b = 18.858(4) Angstrom, c = 6.786(1) Angstrom, beta =113.23(3)degrees, Z = 4, V= 752.5(2) Angstrom(3), and II belongs to the Pn (no. 7) space group with a = 6.321(2) Angstrom, b = 11.841(2) Angstrom, c = 6.932(2) Angstrom, beta = 111.59(2)degrees, Z = 2, V = 482.4(2) Angstrom(3). Both compounds consist of Cu2SbSe3 layers separated by free ethylenediamine molecules. The intermetallic layers are very similar in I and II, but the orientations of the solvent molecules are different. Both compounds contain copper atoms of mixed-valence, Cu(I) and Cu(II), and both are semiconductors with intermediate band gaps (similar to 1.6 eV).