12136-50-4Relevant articles and documents
Ion-exchangeable cobalt polysulfide chalcogel
Shafaei-Fallah, Maryam,He, Jiaqing,Rothenberger, Alexander,Kanatzidis, Mercouri G.
, p. 1200 - 1202 (2011)
We present a promising approach in synthetic chalcogel chemistry that is extendable to a broad variety of inorganic spacers. Polychalcogenide aerogels with ion-exchange properties are demonstrated in cobalt polysulfide. The new materials show a broad range of pore sizes and high surface area of 483 m 2/g.
Kx[Bi4- xMnxS6], Design of a Highly Selective Ion Exchange Material and Direct Gap 2D Semiconductor
Wang, Ruiqi,Chen, Haijie,Xiao, Yi,Hadar, Ido,Bu, Kejun,Zhang, Xian,Pan, Jie,Gu, Yuhao,Guo, Zhongnan,Huang, Fuqiang,Kanatzidis, Mercouri G.
, p. 16903 - 16914 (2019)
Layered sulfides with high selectivity for binding heavy metal ions and radionuclide ions are promising materials in effluent treatment and water purification. Here we present a rationally designed layered sulfide Kx[Bi4-xMnxS6] (x = 1.28) deriving from the Bi2Se3-structure type by targeted substitution to generate quintuple [Bi4-xMnxS6]x- layers and K+ cations between them. The material has dual functionality: it is an attractive semiconductor with a bandgap of 1.40 eV and also an environmental remediation ion-exchange material. The compound is paramagnetic, and optical adsorption spectroscopy and DFT electronic structure calculations reveal that it possesses a direct band gap and a work function of 5.26 eV. The K+ ions exchange readily with alkali or alkaline-earth ions (Rb+, Cs+, and Sr2+) or soft ions (Pb2+, Cd2+, Cr3+, and Zn2+). Furthermore, when the K+ ions are depleted the Mn2+ ions in the Bi2Se3-type slabs can also be replaced by soft ions, achieving large adsorption capacities. The ion exchange reactions of Kx[Bi4-xMnxS6] can be used to create new materials of the type Mx[Bi4-xMnxS6] in a low temperature kinetically controlled manner with significantly different electronic structures. The Kx[Bi4-xMnxS6] (x = 1.28) exhibits efficient capture of Cd2+ and Pb2+ ions with high distribution coefficient, Kd (107 mL/g), and exchange capacities of 221.2 and 342.4 mg/g, respectively. The material exhibits excellent capacities even in high concentration of competitive ions and over a broad pH range (2.5-11.0). The results highlight the promise of the Kx[Bi4-xMnxS6] (x = 1.28) phase to serve not only as a highly selective adsorbent for industrial and nuclear wastewater but also as a magnetic 2D semiconductor for optoelectronic applications.
Understanding fluxes as media for directed synthesis: In situ local structure of molten potassium polysulfides
Shoemaker, Daniel P.,Chung, Duck Young,Mitchell,Bray, Travis H.,Soderholm,Chupas, Peter J.,Kanatzidis, Mercouri G.
, p. 9456 - 9463 (2012/07/14)
Rational exploratory synthesis of new materials requires routes to discover novel phases and systematic methods to tailor their structures and properties. Synthetic reactions in molten fluxes have proven to be an excellent route to new inorganic materials because they promote diffusion and can serve as an additional reactant, but little is known about the mechanisms of compound formation, crystal precipitation, or behavior of fluxes themselves at conditions relevant to synthesis. In this study we examine the properties of a salt flux system that has proven extremely fertile for growth of new materials: the potassium polysulfides spanning K2S3 and K 2S5, which melt between 302 and 206 °C. We present in situ Raman spectroscopy of melts between K2S3 and K 2S5 and find strong coupling between n in K 2Sn and the molten local structure, implying that the Sn2- chains in the crystalline state are mirrored in the melt. In any reactive flux system, K2Sn included, a signature of changing species in the melt implies that their evolution during a reaction can be characterized and eventually controlled for selective formation of compounds. We use in situ X-ray total scattering to obtain the pair distribution function of molten K2S5 and model the length of Sn2- chains in the melt using reverse Monte Carlo simulations. Combining in situ Raman and total scattering provides a path to understanding the behavior of reactive media and should be broadly applied for more informed, targeted synthesis of compounds in a wide variety of inorganic fluxes.
Synthesis and crystal structure of KCuGd2S4: A threedimensional framework with isolated channels
Stoll, Petra,Duerichen, Peter,Naether, Christian,Bensch, Wolfgang
, p. 1807 - 1810 (2008/10/09)
The reaction of K2S5, Cu, Gd, and S in a 2:1:2:4 molar ratio at 450°C yields yellow-orange needle-like cuboids of the new quaternary compound KCuGd2S4. The crystal structure represents a novel three-dimensional structure type of quaternary rare earth chalcogenides with alkali metal. The compound crystallizes in the orthorhombic space group Cmcm (No. 63) with a = 3.9921(1) A, b = 13.523(3) A, c = 13.802(3) A, V = 745.1(3) A3, Z = 4. In the structure Gd6 octahedra and CuS4 tetrahedra are joined by common edges and corners forming corrugated layers parallel to (010). The GdS6 octahedra are connected via common edges in the third dimension thus leading to the formation of a three-dimensional tunnel structure. The potassium cations are confined within the pentagonal shaped channels and are surrounded by eight sulfide anions each.
Syntheses and characterization of the new homoleptic indium-polysulfide complexes [In2S27]4-, [In2S14]2-, and [In2S16]2-
Dhingra, Sandeep S.,Kanatzidis, Mercouri G.
, p. 3300 - 3305 (2008/10/08)
The reaction of InCl3 with K2S5 and Ph4PCl in a 2:5:4 mole ratio in DMF afforded thin pale yellow crystals of (Ph4P)4[In2S27] (I). I crystallizes in the triclinic space group P1 (No. 2) with a = 12.276(3) ?, b = 21.849(8) ?, c = 10.852(2) ?, α = 99.57(2)°, β = 112.44(2)°, γ = 79.28(3)°, V = 2628(1) ?3 (at -90°C), and Z = 1. The [In2(S4)2(S6)2(S 7)]4- anion consists of In3+ centers in trigonal bipyramidal coordination. Each In atom is chelated by two bidentate polysulfide S42- and S62- ligands forming a [In(S4)(S6)]- unit. Two [In(S4)(S6)]- units are bridged by an S72- chain forming a dimer. A similar reaction of InCl3 with K2S5 and Ph4PCl in a slightly different mole ratio of 1:2:1 in DMF afforded pale yellow crystals of (Ph4P)2{[In2S14] 0.5[In2S16]0.5} (II). II crystallizes in the triclinic space group P1 (No. 2) with a = 10.906(2) ?, b = 11.892(2) ?, c = 21.554(3) ?, α = 89.81(1)°, β = 97.46(1)°, γ = 92.25(1)°, V = 2769(1) ?3 (at -80°C), and Z = 2. II is a cocrystallizate of [In2S14]2- and [In2Si6]2- anions with equal occupancies. The two anions contain tetrahedral In3+ centers. The In atoms are bridged by an S2- and an S52- ligand to form an eight-membered [In2S(S5)]2+ ring core in an extreme cradle configuration. The remaining two coordination sites on each In atom are occupied by a S42- chelating ligand on one side and a S42- or a S62- chelating ligand disordered on the other. These complexes show no absorption peaks in the UV/vis region of the spectrum. The solid-state far-IR spectra of the compounds exhibit strong absorptions in the 500-100-cm-1 region due to the S-S and M-S stretching vibrations. Thermal gravimetric analysis data for these compounds are reported.
The action of hydrogen sulfide on chromates: Potassium dichromate
Dunnicliff,Kotwani,Hamid
, p. 1217 - 1229 (2008/10/08)
The brown solid formed in the intermediate stages of the reduction of 5 per cent potassium dichromate by hydrogen sulfide consists of chromium dioxide and hydroxide, a cooerdinated chromium thiosulfate, chromium tetrathionate, and free sulfur, while the filtrate contains unattacked potassium dichromate together with potassium thiosulfate and tetrathionate. The amount of tetrathionate decreases with the amount of chromate present, until eventually both disappear simultaneously. So long as chromate remains sulfide is not present, and the dichromate accounted for as thiosulfate is less than theory by the amount of tetrathionate formed. Accepting views previously advanced (3, 4) for the development of thiosulfate in these reactions, it has been shown that thiosulfate is the source of the tetrathionate formed in a side reaction, owing to the mild oxidation of part of the thiosulfate by chromate. The tetrathionate is ultimately reduced to thiosulfate by the alkaline sulfide. Sulfate is not formed in these reductions if the concentration of hydroxyl ions is above a certain critical value. The final products are (a) a precipitate containing chromium hydroxide, sulfur, and a complex chromium thiosulfate in which the ratio of ionic to cooerdinated thiosulfate is approximately 2:1, and (b) potassium thiosulfate and polysulfide in solution. The polysulfide formed depends on the temperature of the reaction, being K2S3 at laboratory temperatures and the pentasulfide at temperatures approaching 90°C.
