Abstract
We used the molten alkali metal polychalcogenide flux method to prepare the new compounds ABiP2S7 (A = K, Rb), A3M(PS4)2 (A = K, Rb, Cs; M = Sb, Bi), Cs3Bi2(PS4)3, and Na0.16Bi1.28P2S6. KBiP2S7 crystallizes in the monoclinic space group P21/c with a = 9.500(3) Å, b = 12.303(4) Å, c = 9.097(3) Å, β = 90.59(3)○, V = 1063 Å3, at 23°C. Dcalc = 3.34 g cm-3, μ = 184.85 cm-1, 2θmax = 50○ Mo Kα. Data with I>3σ-(I) 1672, R/Rw(%) = 2.8/3.1. K3Bi(PS4)2 crystallizes in the orthorhombic space group P212121 with a = 23.894(8)(3) Å, b = 6.799(3) Å, c = 9.049(2) Å, V = 1470 Å3, at -60°C. Dcalc = 2.91 g cm-3, μ = 140.8 cm-1, 2θmax = 50○. Data with I>3σ(I) 1745, R/Rw(%) = 5.5/6.0. Cs3Bi2(PS4)3 crystallizes in the monoclinic space group P21/c with a = 18.091(5) Å, b = 6.791(2) Å, c = 18.723(3) Å, β = 97.95(2)○, V = 2278 Å3, at 23°C. Dcalc = 3.77 g cm-3, μ = 213.3 cm-1, 2θmax = 50○. Data with I>3σ(I) 2623, R/Rw(%) = 7.0/9.0. Na0.16Bi1.28P2S6 crystallizes in the monoclinic space group F21/n with a = 6.554(2) Å, b = 7.297(2) Å, c = 9.371(1) Å, β = 92.04(2)○, V = 447.8 Å3, at 23°C. Dcalc = 3.73 g cm-3, μ = 236.2 cm-1, 2θmax = 50○. Data with I>3σ(I) 892, R/Rw(%) = 7.7/8.5. The structural diversity in this family of compounds ranges from the one-dimensional non-centrosymmetric chains of A3M(PS4)2 and the layered compounds, ABiP2S7 and Cs3Bi2(PS4)2, to the dense three-dimensional framework of Na0.16Bi1.28P2S6. KBiP2S7 is a layered solid with a complex new structure type, where corrugated layers are separated by eight-coordinate K+ ions. It contains a [P2S7]4- ligand in a complicated coordination mode. The structure of K3Bi(PS4)2 is assembled from one-dimensional, helical [Bi(PS4)2]3n-n chains running along the crystallographic b-axis. The chain structure features two interesting binding modes for a tetrahedral [PS4]3- ligand. The structure of Cs3Bi2(PS4)3 has layers containing the same one-dimensional helical chains observed in K3Bi(PS4)2. However, the PS4 unit acts as a bridge to a Bi2(PS4)2 dimeric unit. This unit is linked to another chain via a second bridging PS4 ligand to form sheets that are parallel to the [101] crystallographic plane. The structure of Na0.16Bi1.28P2S6 is three dimensional but consists of layers of P2S6 groups in the a-b plane separated by a single layer of Bi3+ ions. The ethane-like [P2S6]4- ligand chelates to eight Bi atoms in a very convoluted fashion. Positional disorder was found between Na and Bi ions in one crystallographic site. Their synthesis, structural characterization, optical absorption and thermal properties are reported.
Original language | English |
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Pages (from-to) | 70-85 |
Number of pages | 16 |
Journal | Journal of Alloys and Compounds |
Volume | 236 |
Issue number | 1-2 |
DOIs | |
Publication status | Published - Apr 1 1996 |
Keywords
- Alkali polychalcogenide fluxes
- Antimony
- Bismuth
- Properties
- Quaternary thiophosphates
- Synthesis
ASJC Scopus subject areas
- Mechanics of Materials
- Mechanical Engineering
- Metals and Alloys
- Materials Chemistry