12136-49-1Relevant articles and documents
Reactions in molten alkalimetal polychalcogenides: What happens in the melt? A study of the reactions in the system K-Nb-S using differential scanning calorimetry, infrared spectroscopy, and X-ray powder diffraction
Dürichen, Peter,Bensch, Wolfgang
, p. 1382 - 1386 (2002)
The reactions of potassium polysulfides with elemental Nb were investigated with different analytical techniques. The amount of the polysulfide applied has no influence onto product formation, i. e. the ratio K2Sx: Nb is not important. The length of the polsysulfide chain, i. e. the value of x in K2Sx determines what product is formed. In sulfur-poor melts, K3NbS4 is observed. Increasing x to 5-6, K4Nb2S11 is formed with a structure containing S22- anions. Finally, applying a melt with x > 6, K6Nb4S25 is found as the product with a crystal structure containing the S52- polysulfide anion. When K2Sx (x 2S5 is formed. Immediately after melting of K2S5 a reaction with elemental Nb occurs. The results of FT-IR and X-ray investigations have demonstrated that after oxidation the anion [Nb2S11]4- is formed relatively fast, and after a short time crystalline K4Nb2S11 can be detected. After 24 h the reaction is complete.
Syntheses and Crystal Structures of New Quaternary Ag-Containing Group 5 Chalcogenides: KAg2MVSe4 and K 3Ag3MV2S8 (MV = Nb, Ta)
Chen, Wen-Tong,Ma, Hong-Wei,Guo, Guo-Cong,Deng, Lei,Zhou, Guo-Wei,Dong, Zhen-Chao,Huang, Jin-Shun
, p. 505 - 509 (2004)
Four new quaternary Ag-containing group 5 chalcogenides, KAg 2NbSe4 (1), KAg2TaSe4 (2), K 3Ag3Nb2S8 (3), and K 3Ag3Ta2S8 (4), have been prepared through the use of molten alkali metal polychalcogenides as reactive fluxes and structurally characterized by single-crystal X-ray diffraction techniques. The layer-type structures of 1 and 2 can be regarded as constructed from the basic building block of the incomplete cubane [Ag3MVSe 3], which are corner-shared to form an infinite chain along the a direction. These incomplete cubane chains are interconnected and further bridged by Se atoms along the c direction, leading to a two-dimensional structure. The crystal structure of 3 and 4 consists of one-dimensional triple-metal [Ag3MV2S8] 3- anionic chains seperated by K+ cations. The alternate packing of MVS4 and AgS4 tetrahedra via edge-sharing along the b direction leads to mixed-metal sub-chains, every two of which are further linked by AgS4 tetrahedra along the a direction through edge-sharing to the MVS4 tetrahedra, thus yielding the so-called triple-metal chains.
Aluminum anodic behavior in aqueous sulfur electrolytes
Licht, Stuart,Jeitler, James R.,Hwang, Jin H.
, p. 4959 - 4965 (1997)
We report on an unexpected domain of high Coulombic efficiency for electrochemical oxidation of aluminum in aqueous polysulfide solutions at high current density for the process: Al + 3OH- → Al(OH)3 + 3e-. This high-efficiency domain, of importance to battery processes, includes aluminum oxidation in a wide range of solutions containing concentrated dissolved zerovalent sulfur. As expected at lower concentrations of dissolved sulfur, aluminum electrochemical oxidation is inefficient, due to various exothermic parasitic reactions, including: Al(c) + ySx2-(aq) + yH2O(1) ? 1/2Al2S3(C) + yOH-(aq) + yHS-(aq), y = 1.5/(x - 1), and Al(c) + 1.5S22-(aq) + 3H2O(1) ? Al(OH)3(amorph) + 3HS-(aq). However, at high polysulfide and sulfur concentrations, the Coulombic efficiency can approach 100%. This domain of high efficiency is correlated to an observed cathodic shift with increasing sulfur concentration, leading to improved chemical passivation at the aluminum surface.
Highly efficient iodine capture by layered double hydroxides intercalated with polysulfides
Ma, Shulan,Islam, Saiful M.,Shim, Yurina,Gu, Qingyang,Wang, Pengli,Li, Hao,Sun, Genban,Yang, Xiaojing,Kanatzidis, Mercouri G.
, p. 7114 - 7123 (2014)
We demonstrate strong iodine (I2) vapor adsorption using Mg/Al layered double hydroxide (MgAl-LDH) nanocomposites intercalated with polysulfide (Sx2-) groups (Sx-LDH, x = 2, 4, 6). The as-prepared LDH/polysulfide hybrid materials display highly efficient iodine capture resulting from the reducing property of the intercalated polysulfides. During adsorption, the I2 molecules are reduced to I3- anions by the intercalated [Sx]2- groups that simultaneously are oxidized to form S8. In addition to the chemical adsorption, additional molecular I2 is physically captured by the LDH composites. As a result of these parallel processes, and despite their very low BET surface areas, the iodine capture capacities of S2-LDH, S4-LDH, and S6-LDH are 1.32, 1.52, and 1.43 g/g, respectively, with a maximum adsorption of 152% (wt %). Thermogravimetric and differential thermal analysis (TG-DTA), energy dispersive X-ray spectroscopy (EDS), and temperature-variable powder X-ray diffraction (XRD) measurements show the resulting I3- ions that intercalated into the LDH gallery have high thermal stability (￥350 °C). The excellent iodine adsorption performance combined with the facile preparation points to the Sx-LDH systems as potential superior materials for adsorption of radioactive iodine, a waste product of the nuclear power industry.
