Carbon binary sulfides

Recently, rhodium and ruthenium-based carbon-supported sulfide electrocatalysts were synthesized by different established methods and evaluated as ODP cathodic catalysts in a chlorine-saturated hydrochloric acid environment with respect to both economic and industrial considerations [46]. In particular, patented E-TEK methods as well as a non-aqueous method were used to produce binary RhjcSy and Ru Sy in addition, some of the more popular Mo, Co, Rh, and Redoped RuxSy catalysts for acid electrolyte fuel cell ORR applications were also prepared. The roles of both crystallinity and morphology of the electrocatalysts were investigated. Their activity for ORR was compared to state-of-the-art Pt/C and Rh/C systems. The Rh Sy/C, CojcRuyS /C, and Ru Sy/C materials synthesized by the E-TEK methods exhibited appreciable stability and activity for ORR under these conditions. The Ru-based materials showed good depolarizing behavior. Considering that ruthenium is about seven times less expensive than rhodium, these Ru-based electrocatalysts may prove to be a viable low-cost alternative to Rh Sy systems for the ODC HCl electrolysis industry. 

The IR spectra in Fig.7 indicate the preferential adsorption of NO on the Co sites. It may be conjectured that the Mo sulfide species are physically covered by the Co sulfide species or that Co-Mo mixed sulfide species are formed and the chemical natures of the Co and Mo sulfides are mutually modified. The Mo K-edge EXAFS spectra were measured to examine the formation of mixed sulfide species between Co and Mo sulfides. The Fourier transforms are presented in Fig.8 for MoSx/NaY and CoSx-MoSx/NaY. The structural parameters derived from EXAFS analysis are summarized in Table 1. The structure and dispersion of the Mo sulfides in MoSx/NaY are discussed above. With the Co-Mo binary sulfide catalyst, the Mo-Co bondings are clearly observed at 0.283 nm in addition to the Mo-S and Mo-Mo bondings. The Mo-Co distance is close to that reported by Bouwens et al. [7] for a CoMoS phase supported on activated carbon. Detailed analysis of the EXAFS results for CoSx-MoSx/NaY will be presented elsewhere. It is concluded that the Co-Mo mixed sulfides possessing Co-S-Mo chemical bondings are formed in CoSx-MoSx/NaY. 

No binary sulfide has been reported, but the bright yellow oxysulfide, PaOS, isostructural with other actinide oxysulfides, has been obtained (125) by heating protactinium pentachloride or pentoxide in a mixture of carbon disulfide and hydrogen sulfide at 900° and 1200°C, respectively... 

CdS Yj Fd3m a=11.172 Z=8 Spinel-type. X, powder. Heating stoichiometric mixtures of the binary carbonates or sulfides in a CSj stream at 1000-1200 °C (He as carrier). 73Yiml... 

CujS-DyjSj Solid solution in the range Dy2Ss CuDysSg I43d a=8.308-8.322 Th3P4-type. X, powder. Appropriate mixtures of the binary sulfides heated in evacuated sihca tubes or in boats of vitreous carbon in a H2S-stream. 72 Ml... 

Stoichiometric mixtures of the binary sulfides heated at 1200°C under streaming H2S in a boat of vitreous carbon. 

The (compositionally) simplest mineral class comprises the native elements, that is, those elements, either metals or nonmetals that occur naturally in the native state, uncombined with others. Native gold, silver, and copper, for example, are metals that naturally occur in a ductile and malleable condition, while carbon - in the form of either graphite or diamond -and sulfur are examples of nonmetallic native elements. Next in compositional complexity are the binary minerals composed of two elements a metal or nonmetallic element combined with oxygen in the oxides, with a halogen - either fluorine, chlorine bromine, or iodine - in the halides, or sulfur, in the sulfides. The oxide minerals, for example, are solids that occur either in a somewhat hard, dense, and compact form in mineral ores and in rocks, or as relatively soft, unconsolidated sediments that melt at moderate to... 

The solubilities of ammonia, carbon dioxide, and hydrogen sulfide were obtained from binary data and expressed in terms of a Henry s constant for infinite dilution and an interaction parameter ... 

Binary Selenides. Most binary selenides are formed by heating selenium in the presence of the element, reduction of selenites or selenates with carbon or hydrogen, and double decomposition of heavy-metal salts in aqueous solution or suspension with a soluble selenide salt, eg, Na2Se or (NH Se [66455-76-3]. Atmospheric oxygen oxidizes the selenides more rapidly than the corresponding sulfides and more slowly than the tellurides. Selenides of the alkali, alkaline-earth metals, and lanthanum elements are water soluble and readily hydrolyzed. Heavy-metal selenides are insoluble in water. Polyselenides form when selenium reacts with alkali metals dissolved in liquid ammonia. Metal (M) hydrogen selenides of the M HSe type are known. Some heavy-metal selenides show important and useful electric, photoelectric, photo-optical, and semiconductor properties. Ferroselenium and nickel selenide are made by sintering a mixture of selenium and metal powder. 

Figure 15.5. Adsorption of binary mixtures (1) ethane + ethylene. Type 4A MS 25°C, 250Torr (2) ethane + ethylene. Type 4A MS, 25°C, 730Torr (3) ethane + ethylene. Type 4A MS, 75°C, 730Torr (4) carbon dioxide + hydrogen sulfide. Type 5A MS, 27°C, 760Torr (5) n-pentane + n-hexane, type 5A MS, 100°C, 760 Torr (6) ethane + ethylene, silica gel, 25°C, 760 Tort (7) ethane + ethylene, Columbia G carbon, 25°C, 760 Torr (8) acetylene + ethylene. Type 4A MS, 31°C, 740 Torr. (Data from Union Carbide Corp.)...

Of the natural gas components that form simple hydrates, nitrogen, propane, and iso-butane are known to form structure II. Methane, ethane, carbon dioxide, and hydrogen sulfide all form si as simple hydrates. Yet, because the larger molecules of propane and iso-butane only fit into the large cavity of structure II, natural gas mixtures containing propane and iso-butane usually form structure II hydrate (see Section 2.1.3.3 in the subsection on structural changes in binary hydrate structure). 

The phase equilibria data for binary guest mixtures are listed under the lighter component. For example, under the heading of binary guest mixtures of methane will be found data for methane + ethane, methane + propane, methane + isobutane, methane + n-butane, methane + nitrogen, methane + carbon dioxide, and methane + hydrogen sulfide. Concentrations are in mole percent or mole fraction in the gas phase, unless otherwise indicated. 

When applying an equation of state to both vapor and liquid phases, the vapor-liquid equilibrium predictions depend on the accuracy of the equation of state used and, for multicomponent systems, on the mixing rules. Attention will be given to binary mixtures of hydrocarbons and the technically important nonhydrocarbons such as hydrogen sulfide and carbon dioxide -Figures 6-7. 

Solution The first two ions are single atom anions and are called sulfide and nitride. The next two are binary ionic compounds, calcium fluoride and potassium sulfide. The polyatomic ions hydroxide and sulfate are present in sodium hydroxide and sodium sulfate. Finally, the last two compounds are covalently bonded and are called sulfur trioxide and carbon tetrachloride. 

The binary mixture hydrogen sulfide + carbon dioxide is the most important non-aqueous system involved in acid gas injection, since acid gas is composed almost exclusively of these components. 

Two early studies of the phase equilibrium in the system hydrogen sulfide + carbon dioxide were Bierlein and Kay (1953) and Sobocinski and Kurata (1959). Bierlein and Kay (1953) measured vapor-liquid equilibrium (VLE) in the range of temperature from 0° to 100°C and pressures to 9 MPa, and they established the critical locus for the binary mixture. For this binary system, the critical locus is continuous between the two pure component critical points. Sobocinski and Kurata (1959) confirmed much of the work of Bierlein and Kay (1953) and extended it to temperatures as low as -95°C, the temperature at which solids are formed. Furthermore, liquid phase immiscibility was not observed in this system. Liquid H2S and C02 are completely miscible. 

Robinson and Bailey (1957) and Robinson et al. (1959) studied the VLE in the ternary mixtures of hydrogen sulfide + carbon dioxide + methane. These investigations also included a few points for the binary system H2S + C02. The points for the binary mixtures were at temperatures between 4° and 71 °C and at pressures from 4 to 8 MPa. 

For mixtures of carbon dioxide and hydrogen sulfide, a binary critical locus extends from the critical point of COz and terminates at the critical point of H2S. This is the case for H2S and COz, but not for all binary mixtures. 

For binary mixtures of hydrogen sulfide and carbon dioxide, the critical locus extends uninterrupted from the critical point of C02 to that of H2S. The critical point of a binary mixture can be estimated from the next two figures. Figure 3.4 shows the critical temperature as a function of the composition, and figure 3.5 gives the critical pressure. 

In addition, potential application of materials containing carbon-sulfur bonds in electronic industries has recently provided an impetus for the synthesis of further binary carbon sulfides, leading to the discovery and characterization of C3 S7,... 

Although binary carbon sulfides appear to be something of a curiosity at the moment, given their stability (especially compared to binary S-N compounds) and their usefulness in the synthesis of new organosulfur compounds and ligands that may be redox active, it is to be expected that their chemistry will develop rapidly over the next few years. 

Electrochemical reduction of CS2 in either DMF or MeCN yields the trithiocarbonate (16) and the 4,5-dimercapto-l,3-dithiole-2-thione (17) dianions, which on oxidation by iodine give the binary carbon sulfide C3S6 in good yields (equations 111 and 112). ... 

A substance is considered soluble if more than three grams of the substance dissolves in 100 ml of water. The more common rules are listed below. 1. All common salts of the group 1A elements and ammonium ions are soluble. 2. All common acetates and nitrates are soluble. 3. All binary compounds of group 7A elements (other than F) with metals are soluble except those of silver, mercury(l), and lead. 4. All sulfates are soluble except those of barium, strontium, lead, calcium, silver, and mercury(l). 5. Except for those in Rule 1, carbonates, hydroxides, oxides, sulfides, and phosphates are insoluble. ... 

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