POLYTHIOANTIMONATE FLUX SYNTHESIS OF THE LOW-DIMENSIONAL COMPOUNDS A(2)AUSBS(4) (A = RB, CS)

The reaction of Au with a molten mixture of A(2)S/Sb/S (A=Rb, Cs) prod uced the isostructural quaternary compounds A(2)AuSbS(4). The yellow-b rown crystals of Rb2AuSbS4 (I) and yellow crystals of Cs2AuSbS4 (II) a re stable in air and water for several days and for over a month for I and II, respectively. The structure of Rb2AuSbS4 crystallizes in the space group Pbcm (not equal 57) and at 23 degrees C a=6.804(3) Angstro m, b=20.127(4) Angstrom, c=7.195(4) Angstrom, V=985(1) Angstrom(3), Z= 8. Final R/R-w=4.5/6.6%. This structure consists of one-dimensional [A uSbS4](n)(2n-) chains separated by A(+) cations. The chains are compri sed of Au+ cations linearly coordinated to [SbS4](3-) tetrahedra. The compounds were characterized with differential thermal analysis (DTA), far-IR, Raman, and solid-state UV/vis diffuse reflectance spectroscop y. (C) 1998 Elsevier Science S.A. All rights reserved.