Abstract: The review concerns methods of synthesis, as well as the molecular, electronic, and crystal structures and the magnetic properties of a novel class of paramagnetic compounds, namely, chalcogen-nitrogen π-heterocyclic radical anion salts derived from 1,2,5-chalcogenadiazole.

Abstract: The oxygen reduction reaction (ORR) in alkaline media has been investigated on chalcogen-modified ruthenium nanoparticles (Ru/C, Se/Ru/C, Se/RuMo/C, S/Ru/C, S/RuMo/C) synthesized in-house via aqueous routes. In acidic medium, it is well known that modification by a chalcogen prevents the oxidation of the underlying transition-metal (Ru) surface, thereby promoting direct molecular O2 adsorption on the Ru metal. On an unmodified Ru catalyst in alkaline media, the surface oxides on Ru mediate the 2e– reduction of molecular O2 to a stable peroxide anion (HO2–) intermediate via an outer-sphere electron-transfer mechanism. This increases the activity of HO2– near the electrode surface and decreases the overpotential for ORR by effectively carrying out the reduction of HO2– to OH– at the oxide-free ruthenium metal site. An increase in ORR activity of Ru is observed by modification with a chalcogen; however, the increase is not as significant as observed in acidic media. Ternary additives, such as Mo, were found...

Abstract: Techniques for preparing chalcogen-containing solutions using an environmentally benign borane-based reducing agent and solvents under ambient conditions, as well as application of these solutions in a liquid-based method for deposition of inorganic films having copper (Cu), zinc (Zn), tin (Sn), and at least one of sulfur (S) and selenium (Se) are provided In one aspect, a method for preparing a chalcogen-containing solution is provided The method includes the following steps At least one chalcogen element, a reducing agent and a liquid medium are contacted under conditions sufficient to produce a homogenous solution The reducing agent (i) contains both boron and hydrogen, (ii) is substantially carbon free and (iii) is substantially metal free

Abstract: Ba2Cu6–xSTe4 and Ba2Cu6–xSeyTe5–y were prepared from the elements in stoichiometric ratios at 1123 K, followed by slow cooling. These chalcogenides are isostructural, adopting the space group Pbam ...

Abstract: An imidazole-functionalized EDT-TTF derivative afforded the protonated cation species in salts with chloranilate and cyananilate. Multi-dimensional networks were formed by acid–base hydrogen-bonds in the imidazolium moiety, and by π-stacks and chalcogen atom interactions in the EDT-TTF moiety.

Abstract: An undoped semiconductor substrate is doped by applying stress at a side of the undoped semiconductor substrate to release self interstitials in the substrate and implanting chalcogen atoms into the side of the substrate. The substrate is annealed to form a first semiconductor region containing the chalcogen atoms and a second semiconductor region devoid of the chalcogen atoms. The first semiconductor region has a doping concentration higher than the doping concentration of the second semiconductor region. The indiffusion of chalcogen atoms into a semiconductor material in the presence of self interstitials can also be used to form field stop regions in power semiconductor devices.

Abstract: Nanoparticles of lead sulfide, selenide and telluride have been synthesized by the reduction of sulfur, selenium or tellurium powder with sodium borohydride (NaBH4) to produce sulfide, selenide or telluride ions, followed by their reaction with a lead salt. In comparison to the chloride, nitrate or sulfate, considerable control of the product is possible when lead carbonate is used as the salt; various shapes of nanoparticles are obtained on varying temperatures and/or times of reaction. The nanoparticles were characterized by infrared spectroscopy (IR), powder X-ray diffraction (PXRD), transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM) and X-ray photoelectron spectroscopy (XPS).

Abstract: Using first-principles density functional theory, we investigate the adsorption properties of chalcogen elements (oxygen and sulfur) on an anionic golden nanocage Au 16 and its effects on the structural and electronic properties of the golden cage. In particular, we find that when a sulfur atom is encapsulated inside Au 16 , its bonding character with Au atoms appears ionic due to electron transfer from sulfur to the gold nanocage. In contrast, the exohedrally adsorbed S atom tends to have strong orbital hybridization with the golden nanocage. For an oxygen adsorption case, electrons from the golden cage tend to be shared with the adsorbed O atom exhibiting strong orbital hybridization, regardless of its adsorption sites. To investigate the transition behaviors between the most stable exohedral and endohedral adsorption configurations, we calculate the activation and reaction energies in the transition. The oxygen atom experiences a lower energy barrier than the sulfur atom due to its smaller atomic radius. Finally, we explore the vibrational properties of S- or O-adsorbed Au 16 buckyballs by calculating their infrared spectra. (Some figures may appear in colour only in the online journal)

Abstract: High-resolution X-ray photoelectron spectroscopy (XPS) is used to study regularities in the formation of valence band electronic structure in binary As x Se100 − x , As x S100 − x , Ge x Se100 − x and Ge x S100 − x chalcogenide vitreous semiconductors. It is shown that the highest occupied energetic states in the valence band of these materials are formed by lone pair electrons of chalcogen atoms, which play dominant role in the formation of valence band electronic structure of chalcogen-rich glasses. A well-expressed contribution from chalcogen bonding p electrons and more deep s orbitals are also recorded in the experimental valence band XPS spectra. Compositional dependences of the observed bands are qualitatively analyzed from structural and compositional points of view.

Abstract: Recent developments in the chemistry of imido and amido derivatives of selenium and tellurium in the +4, +2 and lower oxidation states are discussed. The focus is on providing an understanding of the unusual features of the structures, bonding and reactivities of these labile chalcogen-nitrogen compounds. Trends in properties within the chalcogen group are made by including comparisons with analogous sulfur-nitrogen compounds, where appropriate. For compounds in which the chalcogen is in the +4 oxidation state, the increasing reluctance to engage in pπ-pπ bonding for the heavier chalcogens is readily evident. The impressive variety of cyclic selenium imides in which selenium is in the +2 or lower oxidation states is in stark contrast to the paucity of information available concerning their tellurium analogues. Salient aspects of the ligand behaviour of selenium and tellurium imides are also described. Metal complexes of selenium(IV) and tellurium(IV) diimides are exclusively N,N′-coordinated, whereas cyclic selenium imides behave as chelating Se,Se′-donor ligands.

Abstract: 119Sn atoms produced by radioactive decay of 119Sb impurity atoms in the structure of AsxS1 − x and AsxSe1 − x glasses are stabilized in the form of Sn2+ and Sn4+ ions at arsenic sites and correspond to ionized states of the amphoteric two-electron center with negative correlation energy (Sn2+ is an ionized acceptor, and Sn4+ is an ionized donor), whereas the neutral state of the Sn3+ center is unstable. The fraction of Sn4+ states increases with chalcogen content in glass. 119Sn atoms produced by radioactive decay of 119mTe impurity atoms in the structure of AsxS1 − x and AsxSe1 − x glasses are stabilized at chalcogen sites (they are electrically inactive) and arsenic sites, and the fraction of arsenic atoms decreases with the chalcogen content in glass.

Abstract: Electrochemical synthesis of organic selenium and tellurium compounds as well as different mechanisms of their anodic and cathodic reactions were reviewed. The first part includes the review of the direct synthesis of the title compounds from the elemental selenium and tellurium, the synthesis by anodic reactions using mainly the generation of arylselenium or tellurium cations and the cathodic reduction based on the generation of organoselenium and tellurium anions. These synthetic applications, more interesting for the wider group of organic chemists, are discussed in more detail. Examples of the anodic functionalization (such as acetoxylation or fluorination) leading to new organic chalcogen compounds are also given. The detailed discussion of the anodic behavior of the title compounds is divided into separate parts, each of them devoted to the different class of compounds. They include first of all diaryl, dialkyl and alkylarylselenides and tellurides, most widely investigated for many years, and next diaryl and dialkyl diselenides. However, anodic reactions of some typical heterocyclic selenides and tellurides are also briefly reviewed. Some electrode reactions in which the title compounds play only the role of intermediates are mentioned as well. Finally, electroreduction mechanisms of organoselenium and tellurium compounds are discussed. Keywords: electrochemical synthesis; anodic oxidation; electrochemical reduction; anodic functionalization; phenylselenenyl cation

Abstract: PROBLEM TO BE SOLVED: To solve such problems that although there is a method for obtaining a filmy crystal of a chalcogen compound, in which a metal film composed of Cu, In and Ga is formed, and selenized, the method has a problem in the uniformity and productivity of the film; and that although a filmy crystal of a chalcogen compound having a high uniformity can be obtained by a method capable of obtaining a nano particle containing Cu, In, Ga and Se at a low cost, the resistance value is high, and the characteristics for solar cell applications are not satisfiedSOLUTION: A mixture of a copper salt and an indium salt, a composite hydroxide of copper and indium, or a composite oxide of copper and indium, and selenium or a selenium compound, and a solvent having a boiling point of ≤250°C are mixed to produce a mixed solvent, which is heated at a temperature of 220 to 500°C to obtain a chalcogen compound powder containing Cu, In, Ga, and Se and having an average particle diameter (D) of ≤80 nm and a low carbon amount From a paste of the chalcogen compound powder, a thin film containing Cu, In, Ga and Se and having a low resistance can be obtained

Abstract: The chapter presents the advances in the chemistry of hypervalent derivatives of selenium and tellurium that have emerged in recent years (usually after 1998). These are based on the inclusion of the discussed compounds into particular subsections, arising from the N-Ch-L (AnBm) coding system, in which N stands for the number of valence electrons associated formally with a central chalcogen atom and L shows the number of ligands (A and B stand for the bonding element). The chapter begins with a brief discussion on the nature of bonding, molecular geometry, basic reactivity and pseudorotation mechanisms in hypervalent selenium and tellurium molecules which can be described as 10-Ch-4 and 10-Ch-5 and 12-Ch-6 species. Next, the unstable hypervalent selenium and tellurium structures detected as reactive intermediates are discussed. The remaining part of the chapter is devoted to the presentation of the chemistry of stable compounds. The isolable derivatives are presented in the following order: selenuranes and telluranes, 10-Ch-5 and 12-Ch-5 species, 10-Ch-6 complexes of perchalcogenuranes with Lewis bases, 12-Ch-6 perchalcogenuranes, 12-Ch-5 perchalcogenuranes, and 2N-Ch-N charged pertelluranes (Ch = Te, N > 6). Keywords: hypervalency; 3 center 4 electron bond; pseudorotations; ligand coupling; selenuranes; telluranes; 12-Ch-6 perchalcogenuranes; 12-Ch-5 perchalcogenuranes; 2N-Ch-N charged pertelluranes (Ch = Te, N > 6)

Abstract: The crystal structure and magnetic properties of layered Fe0.5TiS2 − x Se x (0 ≤ x ≤ 2) compounds intercalated by iron atoms have been investigated. It has been shown that the substitution of selenium for sulfur is accompanied by an increase in the unit cell volume, a transition from the ferromagnetic to antiferromagnetic behavior, and a nonmonotonic variation in the paramagnetic Curie temperature. The intercalated iron atoms are characterized by lower values of the effective moment (3.4–4.0μB) as compared to the predicted value (4.89μB) for the Fe2+ ion at g = 2. The results obtained have been discussed under the assumption that there are the hybridization of 3d electronic states of intercalated Fe atoms with the electronic states of the TiS2 − x Se x host compounds and the competition of exchange interactions of different types.

Abstract: PROBLEM TO BE SOLVED: To solve such problems that one of the processes for obtaining a filmy crystal of a chalcogen compound comprises forming a metal film composed of Cu, In, and Ga and treating the film with Se, this process, however, has difficulties in the uniformity of the film obtained and the productivity, the use of a process producing nano particles containing Cu, In, Ga, and Se at a low cost gives a highly uniform filmy crystal of a chalcogen compound, but the filmy crystal has too high a resistance to meet properties required for use in solar cells and the like, because the chalcogen compound obtained by this process contains a large amount of carbon. SOLUTION: The chalcogen compound powder is expressed by the formula: Cu a In b Ga 1-b Se c S d (wherein, 0.65≤a≤1.2; 0≤b≤1; 1.9≤C+d≤2.4), and has an average particle size (D50) of not less than 5 nm and less than 0.5 μm and a carbon content of not larger than 0.2 mass%. The process for producing the chalcogen compound powder includes a step to obtain a chalcogen compound by heating a metal source containing copper and indium having an average primary particle size of not larger than 0.3 μm and at least one kind selected from the group consisting of selenium, selenium compounds, sulfur and sulfur compounds at a temperature of not lower than 200°C and not higher than 400°C in a reducing gas and a step to pulverize the chalcogen compound. COPYRIGHT: (C)2011,JPO&INPIT

Abstract: Recent advances in the electrophilic chemistry of the group 16 elements (the chalcogens) is reviewed with a particular emphasis on their Lewis acidic behavior, a counterintuitive bonding mode for these normally electron rich elements. On going themes include redox reactions between the chalcogen tetrahalides (ChX4; Ch = Se, Te; X = Cl, Br, I) and neutral 2-electron ligands with concomitant reduction of the group 16 centre and elimination of reactive X2 as a by-product. Use of unstable ChX2 circumvents this problem, and strategies to stabilize and use the dihalides is discussed. The use of chalcogen pseudo-halides, where X is an anionic leaving group is presented. Employing these pseudo-halides can eliminate pathways for side reaction, and are easily displaced allowing for the isolation of a variety of highly charged homoleptic coordination complexes.

Abstract: BaCu5.72Se0.46Te6.54, BaCu5.93SeTe6, and BaCu5.92S0.986Te6.014 are synthesized from the elements (silica tubes, 663 K, 240 h) and characterized by single crystal XRD and DFT-based LMTO electronic band structure calculations.

Abstract: The chemistry of compounds with carbon-polonium bonds remains, not surprisingly, rather unstudied because of the high level of radioactivity, and hence scarcity, danger and expense, associated with polonium itself. Attempts to enlighten this understanding have rarely investigated the same species experimentally and theoretically; the former are emphasized in this chapter. Approaches to the syntheses of dialkyl polonides, aryl polonium derivatives and other types of compounds with carbon-polonium bonds are discussed. Keywords: organopolonium compounds; chronicle; radioactivity; dialkyl polonides; aryl polonium derivatives; organobismuth compounds; radioactivity; polonium and other chalcogens; chromatography and radiochromatography

Abstract: The chapter presents the advances in the chemistry of oxoacids of selenium and tellurium and their derivatives, which have emerged in recent years (mostly after 1998) based on the division of the discussed compounds into particular subclasses arising from the oxidation state of a central chalcogen atom. It begins with a brief discussion on the nature of bonding between the chalcogen and oxygen atoms. Next this chapter presents for the first time all the available data on basic synthetic protocols leading to alkane (arene) oxoacids of selenium and tellurium, and the acid halides, esters and amides derived from them. A brief discussion on their structure and reactivity is also included. The derivatives are presented in the following order: (a) divalent, dicoordinated selenenic and tellurenic acids, RChOH (ChSe or Te), and their derivatives; (b) tetravalent, tricoordinated seleninic and tellurinic acids, RCh(O)OH, and their derivatives RCh(O)L (ChSe or Te; LX, OR, NR1R2); (c) hexavalent, tetraacoordinated selenonic and telluronic acids, RCh(O)2OH, and their derivatives RCh(O)2L (ChSe or Te; LX, OR, NR1R2). Keywords: selenenyl derivatives; tellurenyl derivatives; seleninyl derivatives; tellurenil derivatives; selenonyl derivatives; telluronyl derivatives

Abstract: A deposition process includes sputtering of a layer of a material having a chalcogenide compound, the chalcogenide being composed of at least one chalcogen on and at least one electropositive element, in order to increase or to decrease the atomic proportion (%) of the chalcogen ion with respect to the atomic proportion (%) of the electropositive element.

Abstract: The oxidation of organochalcogen compounds to their corresponding radical cations and dications is described. The importance of through space and ‘secondary’ interactions in influencing this oxidation chemistry is illustrated in a number of cases.

Abstract: CuInSe 2 (CISe) absorber films were prepared by selenizing Cu-In metallic films with seleno-amide in a tube furnace for solar cell fabrication. Seleno-amide used in this study is stable at room temperature and decomposes into H 2 Se at below 150 °C. Chalcogen amides allow safe transportation and the handling of chalcogen sources that can produce chalcogen hydrides at reasonably low temperature. Post-selenization annealing at 500°C for various time periods were carried out to reverse the indium inhomogeniety created during selenization and to promote further phase transformation. Cu/In ratio of CISe thin films was reduced from ~1.6 down to ~0.9 through the post-selenization annealing at 500°C for up to 3 hours. The first batch of cells fabricated with soda-lime glass/Mo/CISe/CdS/ZnO/ZnO:Ga structure exhibited power conversion efficiency up to 1.6% without any optimization.