Simultaneous Rietveld refinement of three phases in the Ag-In-S semiconducting system from X-ray powder diffraction

Abstract

Three phases of the Ag-In-S system were simultaneously refined from a single X-ray powder diffraction pattern using the Rietveld method. The X-ray powder pattern was composed of 42.7% of AgIn 5S 8, 32.7% of AgInS 2 (tetragonal phase) and 24.6% of AgInS 2 (orthorhombic phase). The AgInS 2 (tetragonal phase) crystallizes in the space group I-42d (D 11 2d, No. 122), Z = 4, with unit cell parameters a = 5.8760(2) Å, c = 11.2007(7) Å, V = 386.73(3) Å 3. The AgInS 2 (orthorhombic phase) crystallizes in the space group Pna2 1 (C 9 2v, No. 33), Z = 4, with a = 6.9972(6) Å, b = 8.2733(6) Å, c = 6.6939(6) Å, V = 387.51(6) Å 3. The AgIn 5S 8 crystallizes in the space group Fd-3m (O 7 h, No. 227), Z = 8, with a = 10.8265(2) Å, V = 1269.01(4) Å 3. The refinement of 45 instrumental and structural parameters led to R p = 9.1%, R wp = 11.4%, R exp = 8.2% and S = 1.4; R B = 5.6% (AgInS 2 tetragonal), R B = 5.2% (AgInS 2 orthorhombic), R B = 8.9% (AgIn 5S 8 cubic), for 162, 540, and 110 independent reflections, respectively.