Sulfur 54 2+ ion

This reaction is catalyzed by the presence of divalent sulfur — e.g. sulfur ions, substances with S-S links, thioethers, thiazoles. If such substances are present in a chromatogram zone then the iodine applied with the reagent is consumed by reaction with sodium azide according to the above reaction. It is no longer available for the for-... 

The metal and acid labile sulfur contents of these proteins was somewhat lower than expected by comparison with the MoFe proteins. AcP contained 2 0.3 vanadium atoms, 21 1 iron atoms, and 19 0.2 acid-labile sulfur atoms per a2)32 hexamer (172). The a2fi2(S) form of Avl was reported to contain 1.4 0.2 vanadium atoms, 21.4 iron atoms, and 24 acid-labile sulfur ions per molecule, and the afi2 form had lower levels of metal and sulfur (173). 

CNs, the Fe ion is postulated to be coordinated by one SO and a mixture of CO and CNs. The interpretation is based on the temperature factor refinement and pyrolytic analysis of oxidized sulfur species (33). In addition, the bridging ligand is postulated to be an inorganic sulfur ion (instead of an oxo ligand, as proposed for the D. gigas). This... 

Sulfonates, aliphatic la 388, 389 Sulfones lb 321,360 Sulfonic acids la 91 Sulfonylurea derivatives lb 204 Sulfoxides lb 321,358,360,372,373,374 Sulfur compounds lb 338 Sulfur-containing compounds lb 301,339 Sulfur dioxide vapor la 86 -, dipole moment la 97 Sulfur, divalent lb 302 Sulfuric acid la 87,195,333,411,426 Sulfur ions lb 302 Sulfutyl chloride vapor la 86 Sulpyrid lb 268 Sunflower seed oil lb 286 Surfactant-TLC plates la 89 Sweeteners la 44, 388-390 Swep la 108... 

Molybdenum disulfide has a layered structure. Each layer is a sandwich consisting of between two layers of ions (Fig. 9.5). The sulfur ions form trigonal prisms and half of the prisms contain a molybdenum ion in the middle. The chemical reactivity of M0S2 is associated with the edges of the sandwich, whereas the basal planes are much less reactive. The edges form the sites where gases adsorb and where the catalytic activity resides. 

In the acid solution the sulfur ions react rapidly with hydrogen ions to form hydrogen sulfide according to the reaction ... 

Sulfides Metal ion(s) + sulfur ion Galena (composed of lead sulfide), a metal ore, from which lead and also silver (which occurs in galena as an impurity, are extracted Pyrite (composed of iron sulfide), an iron ore... 

Although sulfur vulcanization has been studied since its discovery in 1839 by Goodyear, its mechanism is not well understood. Free-radical mechanisms were originally assumed but most evidence points to an ionic reaction [Bateman, 1963]. Neither radical initiators nor inhibitors affect sulfur vulcanization and radicals have not been detected by ESR spectroscopy. On the other hand, sulfur vulcanization is accelerated by organic acids and bases as well as by solvents of high dielectric constant. The ionic process can be depicted as a chain reaction involving the initial formation of a sulfonium ion (XI) by reaction of the polymer with polarized sulfur or a sulfur ion pair. The sulfonium ion reacts with a polymer molecule by hydride... 

The Cuz active site consists of four copper ions, arranged in a distorted tetrahedron and coordinated by seven histidine residues and one hydroxide anion. This site was detected in nitrous oxide reductase [16, 17] (Figure 5.1g) and is involved in the reduction of N20 to N2. The copper ions in the tetranuclear cluster are bridged by an inorganic sulfur ion [18], which until recently was believed to be a hydroxide anion. Three copper ions are coordinated by two histidine residues, whereas the fourth is coordinated by only one, thus leaving a binding site for the substrate. 

Costonis et al. (33) were unable to demonstrate a positive correlation between ambient sulfur dioxide levels and inorganic sulfur ion accumulation in the needles of pines which are injured by relatively low levels of sulfur dioxide in the air. White pines growing in air polluted with more than 0.25 ppm of sulfur dioxide are often stunted, and a direct correlation can be obtained between plant growth and ambient S02 levels (34). However, tissue analysis does not reveal a measurable rise in sulfur level as inorganic sulfate ions. It is posible that the excess sulfur is incorporated into cell protein, but the data conflict (28, 35). For these reasons, it is not possible to follow sulfur accumulation in plants chronically exposed to low levels of ambient S02 without resorting to labeled S02. 

Signals 1, II, III with varied from 1,941 to 1,995 and gj 1 varied from 1,96 to 1,86 are detected in the ESR spectra (Figure 2). These signals are related with Mos+iones in 0- and 0,S-surrounding [5]. The juxtaposition of the activity run and ESR spectra of the samples after different treatments show that the reversible deactivation effect is related with change in ratio of the Mo5+ species in O and 0,S-surrounding. These sites differ by number and state of sulfur iones in the Mo... 

The study of the HDS activity of HPMo/SiOa as a model catalyst has shown that the reversible deactivation effect is connected with increasing of sulfur iones in Mo5 surrounding, blockage Mos species by S-compounds and deeper reduction of molybdenum. The sample containing only molybdenum sulfide exhibits about two times lower initial and steady thiophene conversion in comparison with partially sulfided HPMo. 

If a sulfur ion, S , has 16 protons and 16 neutrons. Calculate its a) Number of electrons b) Atomic mass number... 

A mineral crystallizes in a cubic closest packed array of sulfur ions with aluminum ions in one-half of the octa-... 

In a parallel set of discoveries, a reflectance band in the visible, similar to that for solid 02, was seen at low latitudes on Ganymede. In addition, a UV feature associated with O3 was seen on Ganymede and on the icy satellites of Saturn. Coupled with these observations was the much earlier discovery of a band indicative of SO2 in ice at Europa and Callisto and the recent discovery of CO2 trapped in the icy surfaces. The SO2 was initially assumed to be due to sulfur ions originating at lo implanted into the ice at Europa, " but the SO2 is also a radiation decomposition product like the O2, as discussed below. " The CO2 source is probably internal as carbon ions have not yet been seen in the plasma. 

---