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21.
Prof. Dr. Vitalijus Janickis 《无机化学与普通化学杂志》2012,638(2):261-274
Abstract. By direct reactions of selenium with halogen and trimethylphenylammonium halogenide and tetraphenylphosphonium, ethyltriphenylphosphonium, and methyltriphenylphosphonium bromides, the tetrahalogenidoselenates(II) – bis(trimethylphenylammonium)tetrabromidoselenate(II) bromide, [NPhMe3]2[SeBr4] · [NPhMe3]Br, a mixed bis(trimethylphenylammonium) tetra(bromido/chlorido)selenate(II), [NPhMe3]2[SeBr4–xClx] · [NPhMe3]2SeBr1–yCly], [NPhMe3]2[SeBr4–xClx],the haxahalogenidodiselenates(II) – bis(trimethylphenylammonium) hexabromidodiselenate(II), [NPhMe3]2[Se2Br6], bis(trimethylphenylammonium) hexachloridodiselenate(II), [NPhMe3]2[Se2Cl6], a mixed bis(trimethylphenylammonium) bromido/chlorido‐diselenate(II), [NPhMe3]2[Se2Br5Cl], bis(tetraphenylphosphonium) hexabromidodiselenate(II), [PPh4]2[Se2Br6], bis(ethyltriphenylphosphonium) hexabromidodiselenate(II), [PEtPh3]2[Se2Br6], and bis(methyltriphenylphosphonium) hexabromidodiselenate(II), [PMePh3]2[Se2Br6], were prepared. By the reaction of selenium with bromine in acetonitrile in the presence of trimethylphenylammonium, benzyltrimethylammonium, and tetramethylammonium bromides, the salts of the unique bromidoselenate(I) anions – bis(trimethylphenylammonium) hexabromidotetraselenate(I), [NPhMe3]2[Se4Br6], bis(benzyltrimethylammonium) hexabromidotetraselenate(I), [NBzMe3]2[Se4Br6], and bis(tetramethylammonium) octadecabromidohexadecaselenate(I), [NMe4]2[Se16Br18], were isolated. First mixed‐valence bromidoselenates(II/I) – bis(tetraethylammonium) octabromidotriselenate(II){dibromidodiselenate(I)}, [NEt4]2[Se3Br8(Se2Br2)], bis(tetraphenylphosphonium) hexabromidodiselenate(II)‐bis{dibromidodiselenate(I)}, [PPh4]2[Se2Br6(Se2Br2)2], and tetrakis(tetramethylammonium) bis{decabromidotetraselenate(II)}‐bis{dibromidodiselenate(I)}, [(CH3)4N]4[(Se4Br10)2(Se2Br2)2] – were synthesized. Mixed bis(trimethylphenylammonium) hexabromidoselenate/tellurate(IV), [NPhMe3]2[Se0.75Te0.25Br6], catena‐poly[(di‐μ‐bromidobis‐{tetrabromidoselenate/tellurate(IV)})‐ μ‐bromine], [NPhMe3]2n[Se1.5Te0.5Br10 · Br2]n were isolated. First mixed‐valence bromidoselenate(IV/I)‐bis(trimethylphenylammonium) hexabromidoselenate(IV)‐bis{dibromidodiselenate(I)}, [NPhMe3]2[SeBr6(Se2Br2)2], a number of mixed bromidochalcogenates(IV/I) – bis(trimethylphenylammonium), bis(tetraethylphosphonium), bis(ethyltriphenylphosphonium) hexabromidotellurates(IV)‐bis{dibromidodiselenates(I)}, [NPhMe3]2[TeBr6(Se2Br2)2], [PEt4]2[TeBr6(Se2Br2)2], [PEtPh3]2[TeBr6(Se2Br2)2], bis(triethylmethylammonium) hexabromidotellurate(IV)‐tris{dibromidodiselenate(I)}, [NMeEt3]2n[TeBr6(Se2Br2)3]n, were synthesized. Mixed‐valence bromidoselenate(IV/II) – bis(methyltriphenylphosphonium) hexabromidoselenate(IV)‐bis{dibromidoselenate(II)},[PMePh3]2[SeBr6(SeBr2)2], received by direct synthesis and two mixed‐valence bromidochalcogenates(IV/II) – bis(methyltriphenylphosphonium) and bis(tetrapropylammonium) hexabromidotellurates(IV)‐selenates(II), [PMePh3]2[TeBr6(SeBr2)2] and [NnPr4]2[TeBr6(SeBr2)2], were synthesized from elemental selenium, tellurium dioxide, and corresponding onium bromide. The structures of all compounds were determined by X‐ray diffraction. 相似文献
22.
Brown crystals of [PPh4]2[Se2Br6] ( 1 ) and [PEtPh3]2[Se2Br6] ( 2 ) were obtained when selenium and bromine reacted in acetonitrile solution in the presence of tetraphenylphosphonium bromide and ethyltriphenylphosphonium bromide, respectively. The crystal structure of 2 has been determined by X‐ray methods and refined to R = 0.0420 for 4161 reflections. The crystals are monoclinic, space group P21/n with Z = 2 and a = 13.055(3) Å, b = 12.628(3) Å, c = 13.530(3) Å, β = 92.40(3)° (293(2) K). In the solid state structure of 2 the dinuclear hexabromo‐diselenate(II) anion is centrosymmetric and consists of two distorted almost square‐planar SeBr4 units sharing a common edge through two bridging Br atoms. The terminal SeII–Br bond distances are found to be 2.419(1) and 2.445(1) Å, the bridging μBr–SeII bond distances 2.901(1) and 2.802(1) Å. 相似文献
23.
Brown crystals of [NMe4]4[(Se4Br10)2(Se2Br2)2] ( 1 ) were obtained from the reaction of selenium and bromine in acetonitrile in the presence of tetramethylammonium bromide. The crystal structure of 1 was determined by X‐ray diffraction and refined to R = 0.0297 for 8401 reflections. The crystals are monoclinic, space group P21/c with Z = 4 and a = 12.646(3) Å, b = 16.499(3) Å, c = 16.844(3) Å, β = 101.70(3)° (123 K). In the solid‐state structure, the anion of 1 is built up of two [Se4Br10]2– ions. Each shows a triangular arrangement of three planar SeBr4 units sharing a common edge through two μ3‐bridging bromine atoms, and one SeBr2 molecule, which is linked to the SeII atoms of two SeBr4 units; between the Se4Br102– ions a dimerized Se2Br2 molecule (Se4Br4) is situated and one SeI atom of each Se2Br2 molecule has two weak contacts [3.3514(14) Å and 3.3952(11) Å] to two bromine atoms of one SeBr4 unit. Four SeI atoms of a dimerized Se2Br2 molecule are in a almost regular planar tetraangular arrangement. Contacts between the SeII atom of the SeBr2 molecule and the SeII atoms of two SeBr4 units are 3.035(1) Å and 3.115(1) Å, and can be interpreted as donor‐acceptor type bonds with the SeII atoms of SeBr4 units as donors and the SeBr2 molecule as acceptor. The terminal SeII–Br and μ3‐Br–SeII bond lengths are in the ranges 2.3376(10) to 2.4384(8) Å and 2.8036(9) to 3.3183(13) Å, respectively. The bond lengths in the dimerized Se2Br2 molecule are: SeI–SeI = 2.2945(8) Å and 3.1398(12), SeI–Br = 2.3659(11) and 2.3689(10) Å. 相似文献
24.
Ingrida Ancutiene Vitalijus Janickis Remigijus Ivanauskas 《Applied Surface Science》2006,252(12):4218-4225
Layers of copper sulfide of varying composition and properties are formed on the surface of polyethylene and polyamide by a sorption-diffusion method using solutions of higher polythionic acids, H2SnO6. The concentration of sulfur adsorbed-diffused into PE and PA depends on the degree of the acid sulfurity, n, the temperature of the solution and the period of the polymer treatment. The amount of copper in a sulfide (CuxS) layer formed after the sulfured polymer treatment with a solution of Cu(I-II) salt is strongly dependent on the concentration of sulfur in the PE and PA. By the chemical analysis of the obtained sulfide layers was determined that a value of x in the CuxS layers varies in the interval 1 < x < 2. The microscopic investigation of transverse sections of PE and PA samples with copper sulfide layers showed that the major part of copper sulfide is in the surface matrix of the polymer. X-ray diffraction studies of the CuxS layers obtained seven phases: with x = 2 (chalcocite), 1.9375 (djurleite), 1.8 (digenite), 1.75 (anilite), 1.12 (yarrowite), 1.06 (talnakhite) and 1 (covellite). The measurements of the electrical conductance of CuxS layers (0.1-4 S cm−2) showed that its value greatly depends on the conditions of PE and PA interaction with H2SnO6 and of further interaction with Cu(I-II) salt solution, on the chemical and phase composition of the layer. 相似文献
25.
Ingrida Bruzaite Valentinas Snitka Vitalijus Janickis 《physica status solidi (a)》2006,203(9):2274-2280
Thallium sulfide layers on the surface of polyethylene are formed if they have been sulfured in a solution of higher polythionic acid, H2S33O6, and then treated with the alkaline solution of thallium(I) sulfate. Three phases TlS, Tl2S, Tl2S2 were identified by X‐ray diffraction analysis in thallium sulfide layers. Surface morphology of the films was characterized with a scanning electron microscope (SEM) and atomic force microscope (AFM). The films deposited on the PE substrate have a no‐homogeneous structure and consist of separated islands, the average roughness up to 10 µm. The deposition on the silica‐polystyrene beads matrix has a homogeneous structure and the average roughness is in the range of 100–150 nm. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
26.
The layers of mixed copper chalcogenides, CuxS-CuyTe, were formed on the surface of polyamide using solutions of potassium and sodium telluropentathionates, K2TeS4O6 and Na2TeS4O6, respectively, and of telluropentathionic acid, H2TeS4O6, as precursors of chalcogens. The concentration of sorbed chalcogens increased with the increasing time of the treatment,
concentration and temperature of precursor solution. CuxS-CuyTe layers are formed on the surface of polyamide after the treatment of chalcogenized polymer with Cu(II/I) salt solution.
The concentration of copper in the layer increases with the increase of chalcogenization duration, concentration and the temperature
of chalcogenization solution. In the surface of CuxS-CuyTe layers various copper, sulfur, tellurium and oxygen compounds (Cu2S, CuS, S8, CuxS, CuyTe, Cu(OH)2 and TeO2) were present. Chalcogenides were the major components in the layer. Chalcogenide phases — digenite, Cu1.8S, djurleite, Cu1.9375S, anilite, Cu7S4, geerite, CuS2, chalcocite, Cu2S, tetragonal Cu3.18Te2, Cu2.72Te, hexagonal Cu2Te, Cu4Te3, Cu1.80Te, Cu1.85Te2, and orthorhombic vulcanite, CuTe were identified in the layers by X-ray diffraction. Electrical sheet resistance of CuxS-CuyTe layers vary from ∼ 1.0 kW cm−2 to 4×103 kΩ cm−2. It is concluded that the formation of chalcogenide layers proceeds in the form of islands which grow into larger agglomerates.
Use of the gathered data enables design and formation of the CuxS-CuyTe layers with desired conductivities.
相似文献
27.
Vytautas Grivickas Andrei Odrinski Vitalijus Bikbajevas Karolis Gulbinas 《physica status solidi b》2013,250(1):160-168
In nominally undoped layered TlGaSe2 crystals the trapping centers have been investigated by photo‐induced current transient spectroscopy (PICTS). Five acceptor and donor traps have been detected. Quite large magnitudes of capture cross‐sections for donor traps at 0.23 and 0.45 eV have been determined. The depth‐resolved free‐carrier absorption (FCA) technique has been applied for the investigation of the majority hole lifetime, τR, at 295 and 77 K. The pronounced τR reduction with increasing injection level is attributed to the trapping effect of the minority electrons which provides a way of estimating trap centers concentration. A moderate τR variation across layer planes is observed but no carrier diffusion related to the recombination on the external crystal surfaces is detected. Moreover, abnormally sharp τR drop is found for carrier concentration above 1017 cm−3. The possibility of excess hole and electron special separation due to compositional stacking faults and the successive their enhanced recombination at high excess carrier concentrations is discussed. 相似文献