12136-60-6Relevant articles and documents
Li7Cd4.5Ge4Se16 and Li6.4Cd4.8Sn4Se16: Strong Nonlinear Optical Response in Quaternary Diamond-Like Selenide Networks
Guo, Yangwu,Li, Xiaoshuang,Feng, Kai,Li, Chao,Zhou, Molin,Wu, Yicheng,Yao, Jiyong
, p. 871 - 876 (2018)
Two new selenides with diamond-like structures, Li7Cd4.5Ge4Se16 and Li6.4Cd4.8Sn4Se16, were synthesized by using a conventional high-temperature solid-state reaction m
Two-Dimensional Substitution: Toward a Better Understanding of the Structure-Transport Correlations in the Li-Superionic Thio-LISICONs
Minafra, Nicolò,Hogrefe, Katharina,Barbon, Federico,Helm, Bianca,Li, Cheng,Wilkening, H. Martin R.,Zeier, Wolfgang G.
, p. 727 - 740 (2021)
A deeper understanding of the relationships among composition-structure-transport properties in inorganic solid ionic conductors is of paramount importance to develop highly conductive phases for future employment in solid-state Li-ion battery applications. To shed light on the mechanisms that regulate these relationships, in this work, we perform a two-dimensional substitution series in the thio-LISICON family Li4Ge1-xSnxS4-ySey. The structural modifications brought up by the elemental substitutions were investigated via Rietveld refinements against high-resolution neutron diffraction data that allowed a precise characterization of the anionic framework and lithium substructure. The analyses show that the anionic and cationic substitutions influence the polyhedral and unit cell volumes in different fashions and that the size of the polyanionic groups alone is not enough to describe lattice expansion in these materials. Moreover, we show that the lithium disorder that is crucial to achieve fast ionic mobility may be correlated to the lithium polyhedral volumes. The correlation of these structural modifications with the transport properties, investigated via electrochemical impedance spectroscopy and 7Li nuclear magnetic resonance spin-lattice relaxation measurements, shows a nonmonotonic behavior of the ionic conductivity and activation energy against the lithium polyhedral volumes, hinting to an optimal size of the conduction pathways for the ionic diffusion. Ultimately, the results obtained in this work will help to establish new guidelines for the optimization of solid electrolytes and gain a more profound understanding of the influence of the substituents on the structure and transport properties of Li-ion conductors.
Cyclic Silylselenides: Convenient Selenium Precursors for Atomic Layer Deposition
Charvot, Jaroslav,Pokorny, Daniel,Zazpe, Raul,Krumpolec, Richard,Pavliňák, David,Hromádko, Luděk,P?ikryl, Jan,Rodriguez-Pereira, Jhonatan,Klikar, Milan,Jelínková, Veronika,Macak, Jan M.,Bure?, Filip
, p. 576 - 579 (2020)
Three cyclic silylselenides were prepared in a straightforward manner. Property tuning has been achieved by varying the ring size and the number of embedded selenium atoms. All silylselenides possess improved resistance towards moisture and oxidation as well as high thermal robustness and sufficient volatility with almost zero residues. The six-membered diselenide proved to be particularly superior Se precursors for atomic layer deposition and allowed facile preparation of MoSe2 layers. Their structure and composition have been investigated by Raman and X-ray photoelectron spectroscopy as well as scanning electron microscopy revealing vertically aligned flaky shaped nanosheets.
Direct thermal neutron detection by the 2D semiconductor 6LiInP2Se6
Chica, Daniel G.,He, Yihui,McCall, Kyle M.,Chung, Duck Young,Pak, Rahmi O.,Trimarchi, Giancarlo,Liu, Zhifu,De Lurgio, Patrick M.,Wessels, Bruce W.,Kanatzidis, Mercouri G.
, p. 346 - 349 (2020)
Highly efficient neutron detectors are critical in many sectors, including national security1,2, medicine3, crystallography4 and astronomy5. The main neutron detection technologies currently used involve 3He-gas-filled proportional counters6 and light scintillators7 for thermalized neutrons. Semiconductors could provide the next generation of neutron detectors because their advantages could make them competitive with or superior to existing detectors. In particular, solids with a high concentration of high-neutron-capture nuclides (such as 6Li, 10B) could be used to develop smaller detectors with high intrinsic efficiencies. However, no promising materials have been reported so far for the construction of direct-conversion semiconductor detectors. Here we report on the semiconductor LiInP2Se6 and demonstrate its potential as a candidate material for the direct detection of thermal neutrons at room temperature. This compound has a good thermal-neutron-capture cross-section, a suitable bandgap (2.06 electronvolts) and a favourable electronic band structure for efficient electron charge transport. We used α particles from an 241Am source as a proxy for the neutron-capture reaction and determined that the compact two-dimensional (2D) LiInP2Se6 detectors resolved the full-energy peak with an energy resolution of 13.9 per cent. Direct neutron detection from a moderated Pu–Be source was achieved using 6Li-enriched (95 per cent) LiInP2Se6 detectors with full-peak resolution. We anticipate that these results will spark interest in this field and enable the replacement of 3He counters by semiconductor-based neutron detectors.
Extended Chemical Flexibility of Cubic Anti-Perovskite Lithium Battery Cathode Materials
Lai, Kwing To,Antonyshyn, Iryna,Prots, Yurii,Valldor, Martin
, p. 13296 - 13299 (2018)
Novel bichalcogenides with the general composition (Li2TM)ChO (TM = Mn, Co; Ch = S, Se) were synthesized by single-step solid-state reactions. These compounds possess cubic anti-perovskite crystal structure with Pm3m symmetry; TM and Li are disordered on the crystallographic site 3c. According to Goldschmidt tolerance factor calculations, the available space at the 3c site is too large for Li+ and TM2+ ions. As cathode materials, all title compounds perform less prominent in lithium-ion battery setups in comparison to the already known TM = Fe homologue; e.g., (Li2Co)SO has a charge density of about 70 mAh g-1 at a low charge rate. Nevertheless, the title compounds extend the chemical flexibility of the anti-perovskites, revealing their outstanding chemical optimization potential as lithium battery cathode material.
Synthesis, crystal structure and lithium motion of Li8SeN 2 and Li8TeN2
Braeunling, Daniel,Pecher, Oliver,Trots, Dmytro M.,Senyshyn, Anatoliy,Zherebtsov, Dmitry A.,Haarmann, Frank,Niewa, Rainer
, p. 936 - 946 (2010)
The compounds Li8EN2 with E = Se, Te were obtained in form of orange microcrystalline powders from reactions of Li2E with Li3N. Single crystal growth of Li8SeN2 additionally succeeded from excess lithium. The crystal structures were refined using single-crystal X-ray diffraction as well as X-ray and neutron powder diffraction data (I41md, No. 109, Z = 4, Se: a = 7.048(1) A, c = 9.995(1) A, Te: a = 7.217(1) A, c= 10.284(1) A). Both compounds crystallize as isotypes with an anionic substructure motif known from cubic Laves phases and lithium distributed over four crystallographic sites in the void space of the anionic framework. Neutron powder diffraction pattern recorded in the temperature range from 3 K to 300 K and X-ray diffraction patterns using synchrotron radiation taken from 300 K to 1000 K reveal the structural stability of both compounds in the studied temperature range until decomposition. Motional processes of lithium atoms in the title compounds were revealed by temperature dependent NMR spectroscopic investigations. Those are indicated by significant changes of the 7Li NMR signals. Lithium motion starts for Li8SeN2 above 150 K whereas it is already present in Li8TeN2 at this temperature. Quantum mechanical calculations of NMR spectroscopic parameters reveal clearly different environments of the lithium atoms determined by the electric field gradient, which are sensitive to the anisotropy of charge distribution at the nuclear sites. With respect to an increasing coordination number according to 2 + 1, 3, 3 + 1, and 4 for Li(3), Li(4), Li(2), and Li(1), respectively, the values of the electric field gradients decrease. Different environments of lithium predicted by quantum mechanical calculations are confirmed by 7Li NMR frequency sweep experiments at low temperatures.
Oxidative Addition to SnII Guanidinate Complexes: Precursors to Tin(II) Chalcogenide Nanocrystals
Ahmet, Ibrahim Y.,Thompson, Joseph R.,Johnson, Andrew L.
, p. 1670 - 1678 (2018)
SnS, SnSe and SnTe are potentially important semiconductor materials. Here, we describe the application of chalcogen containing SnIV guanidinate precursors for the production of tin(II) chalcogenide nanocrystals. Reaction of the stannylene(II)
Syntheses and characterization of some mixed Te/Se polychalcogenide anions [TemSen]2-
Sekar, Perumal,Ibers, James A.
, p. 5436 - 5441 (2004)
Several mixed Te/Se polychalcogenide anions [TemSe n]2- were synthesized at 293 K by reactions between Ten2- and Sen2- anions in N,N-dimethylformamide (DMF) in the presence of different-size ammonium or phosphonium cations, in some cases in the presence of metal species. The structures of these anions were determined by single-crystal X-ray diffraction methods. The crystal structures of (NEt4]2[Te 3Se6] (1) and [NEt4]2[Te 3Se7] (2) consist, respectively, of one-dimensional infinite ∞1[Te3Se6 2-] and ∞1[Te3Se 72-] anionic chains separated by NEt4 + cations. In compound 1, each chain comprises Te3Se 5 eight-membered rings bridged by Se atoms. The Te3Se 5 ring has an open book conformation. The NMR spectrum of a DMF solution of [NEt4]2[Te3Se6] crystals at 223 K shows 77Se resonances at δ = 290, 349, and 771 ppm and a single 125Te resonance at δ = 944.7 ppm. In compound 2, each chain comprises Te3Se6 five- and six-membered rings bridged by Se atoms. The Te3Se6 ring can be regarded as an inorganic analogue of bicyclononane. The anion of [PPh4]2[Te2Se2] (4) contains a Se-Te-Te-Se chain with the terminal Se atoms trans to one another. The new compounds [PPN]2[TeSe10] (3), [NMe4] 2[TeSe3]·DMF (5), and [NEt4] 2[TeSe3] (6) contain known anions.
Traceless selenocarboxylates for the one-pot synthesis of amides and derivatives
Silva, Luana,Rosário, Alisson R.,Machado, Bianca M.,Lüdtke, Diogo S.
supporting information, (2020/12/25)
We have recently reported a one-pot procedure for glycosyl amides synthesis using selenocarboxylate as traceless reagent. Herein, we present a further application of selenocarboxylate-azide reaction for amide bond formation on a broader range of substrates, including heterocyclic systems and fatty acid. This method proved to be highly efficient for the synthesis of primary and secondary amides, sulfonamides, imides, phosphoramide and also carbamate.
