Synthesis and Characterization of Novel One-Dimensional Phases from Supercritical Ammonia:  Cs₃Ag₂Sb₃S₈, α- and β-Cs₂AgSbS₄, and Cs₂AgAsS₄

Abstract

Synthetic efforts utilizing Cs2CO3, Ag, M2S3 (M = As, Sb), and S8 in supercritical ammonia (160 °C) have yielded four novel, one-dimensional compounds in the Cs−Ag−M−S system. These members were characterized by single-crystal X-ray diffraction and diffuse reflectance measurements. Cs3Ag2Sb3S8 (I) crystallizes in the monoclinic space group P21/m with lattice parameters of a = 10.539(3) Å, b = 7.234 (3) Å, c = 12.777 (3) Å, β = 101.96 (2)°, V = 952.7(9) Å3, z = 2, and R = 0.0377 (wR = 0.0445). The columnar framework of this compound consists of [SbS2]∞ - chains and SbS4 3- tetrahedra that are stitched together by Ag(I) ions. When the Cs/Sb ratio is doubled, α- and β-Cs2AgSbS4 (II and III, respectively) are obtained. Both phases contain identical anionic chains which pack in different ways. Compound II crystallizes in the monoclinic space group P21/c with a = 6.848(3) Å, b = 11.413(3) Å, c = 13.187(3) Å, β = 102.45(3)°, V = 1006.5(6) Å3, z = 4, and R = 0.0414 (wR = 0.0498). Compound III was refined in the triclinic space group P1̄ with a = 6.917(2) Å, b = 7.341(2) Å, c = 10.998(2) Å, α = 73.83(2)°, β = 76.08(2)°, γ = 71.71(2)°, V = 502.0(2) Å3, z = 2, and R = 0.0343 (wR = 0.0423). Compound IV, the isostructural arsenic analog of III, Cs2AgAsS4, has also been prepared and structured: a = 6.783(2) Å, b = 7.191(2) Å, c = 11.088(2) Å, α = 73.61(3)°, β = 75.10(3)°, γ = 70.83(3)°, V = 481.9(2) Å3, z = 2, and R = 0.0397 (wR = 0.0601). The infinite, one-dimensional anionic chains in the Cs2AgMS4 phases are built from isolated MS4 3- tetrahedra (M = As, Sb) joined by Ag(I) ions. In all four materials the silver atoms are tetrahedrally coordinated by sulfur atoms, and cesium(I) cations are located in the surrounding voids. Bond valence sums support the electron precise counts predicted for all three members: Cs3 IAg2 ISb2 IIISbVS8 -II and Cs2 IAgIMVS4 -II. Optical bandgaps determined via diffuse reflectance measurements indicate that these are wide bandgap materials (2.1−2.7eV) and thus are in agreement with the expected electronic configurations.

Synthesis, structure, and properties of a new manganese thioantimonate(III),

“…As the absorption spectra of 1 shown in Fig. 4, the obtained absorption versus energy spectra show band gap at 2.23 eV (459 nm), which is in agreement with the color of the crystal and suggest 1 is a semiconductor [27].…”

Infinite Anionic Chains Formed by Alternating Bidentately Acting [SbS4]3- Anions and [Mn(dien)]2+ Complexes in the Compound [Mn(dien)2][Mn(dien)SbS4]2

“…[9 -19]. There are only three examples for the coexistence of Sb(III) and Sb(V) in thioantimonate compounds obtained under solvothermal conditions [20 -22], and another mixed valent thioantimonate, Cs 3 Ag 2 Sb 3 S 8 , was prepared in supercritical ammonia [23].…”

A solvothermal synthesis and structure of K2Ag2GeS4 with the simplest helical chains

“…The tetrahedral GeS 4 is regular one because of the same surrounding linkage. Contrary to Ag þ ions with distorted tetrahedron and trigonal pyramid coordination in the synthetic quaternary Agcontaining chalcogenides [9,10], Ag þ in this compound has a rare coordination, more interestingly the bridging bonds show the different orientations. In helical polynuclear metal complex there are usually two forms of chirality, the first is the chirality at the metal center, and the second is the orientation of the bridging bonds, which determines the sense of rotation of the resulting helix.…”