Stable sulfur isotopes

In addition to the 4 stable isotopes sulfur has at least 9 radioactive isotopes, the one with the longest half-life being which decays by activity (Kmax 0.167 MeV, 87.5 d). can be prepared by Cl(n,p), S(n,> ) or S(d,p) and is commercially available as SeicmcQt H2S, SOCb and KSCN. The radiation has a similar energy to that of C ( mav 0.155 MeV) and similar counting techniques can be used (p. 276). The maximum range is 300 min in air and 0.28 mm in water, and effective shielding is provided by a perspex screen 3-10 mm thick. The preparation of many - S-containii compounds has been... 

In addition to the 4 stable isotopes sulfur has at least 9 radioactive isotopes, the one with the longest half-life being which decays by activity ( max 0.167 MeV, 87.5 d), can be... 

Naturally selenium contains six stable isotopes. Fifteen other isotopes have been characterized. The element is a member of the sulfur family and resembles sulfur both in its various forms and in its compounds. 

There are four stable isotopes of sulfur and S, which have relative abundances of 95.1, 0.74, 4.2, and 0.016%, respectively. The relative... 

R. Krol SE and V. A, Grinenko (eds.). Stable Isotopes Natural and Anthropogenic Sulfur in the Environment, SCOPE Report 43. Wiley. Chichesier. 1991. 466 pp,... 

There are two dominant stable isotopes of sulfur foimd in atmospheric sulfur compounds. 

What are the relative contributions of these two sources Two approaches have been taken. One is to establish the geology and hydrology of a basin in great detail. This has been carried out for the Amazon (Stallard and Edmond, 1981) with the result that evaporites contribute about twice as much sulfate as sulfide oxidation. The other approach is to apply sulfur isotope geochemistry. As mentioned earlier, there are two relatively abundant stable isotopes of S, and The mean 34/32 ratio is 0.0442. However, different source rocks have different ratios, which arise from slight differences in the reactivities of the isotopes. These deviations are expressed as a difference from a standard, in the case of sulfur the standard being a meteorite found at Canyon Diablo, Arizona. 

Natural sulfur is composed of the four stable isotopes S, and... 

The ratios of heavy to light stable isotopes of hydrogen H/iH (or D/H), carbon i C/i C, nitrogen oxygen i 0/i 0, and sulfur 3 5/325 show distinctive patterns of... 

Eighteen isotopes of sulfur, 17 of selenium, 21 of tellurium, and 27 of polonium have been registered of these, 4 sulfur, 6 selenium, and 8 tellurium isotopes are stable, while there is no stable isotope of polonium. None of the naturally occurring isotopes of Se is radioactive its radioisotopes are by-products of the nuclear reactor and neutron activation technology. The naturally occurring, stable isotopes of S, Se, and Te are included in Table 1.2. 

Table 1.2 Naturally occurring, stable isotopes of sulfur, selenium, and tellurium...

Although use of radio and stable isotope labels involving the trio of covalently-bonded nitrogenous functions in 3 and in 78, provided evidence that isocyano is the precursor of the isothiocyano and formamido groups [30, 81], it remains to be shown that a biosynthetic equivalent of the in vitro chemically-proven fusion process between isocyano and free sulfur (e.g., cf. Introduction) exists in the cells of sponges. In marine biota, various ionic forms of sulfur in a number of oxidation states, as well as organo-polysulfides are known. However, any association with the isonitrile group and a sulfated species has yet to be established. 

Table 14.1 Relative abundances of the stable isotopes of hydrogen, carbon, nitrogen, oxygen and sulfur (Hoefs 1996 Schoeller 1999)...

Stable isotopes serve as naturally occurring tracers that can provide much information about how chemical reactions proceed in nature, such as which reactants are consumed and at what temperature reactions occur. The stable isotopes of several of the lighter elements are sufficiently abundant and fractionate strongly enough to be of special usefulness. Foremost in importance are hydrogen, carbon, oxygen, and sulfur. 

Table 19.1. The stable isotopes of hydrogen, carbon, oxygen, and sulfur, and their approximate terrestrial abundances (Wedepohl et al., 1978)...

ORIGIN OF NAME From the Sanskrit word sulvere and the Latin word sulphurim. ISOTOPES There are a total of 24 isotopes of sulfur all but four of these are radioactive. The four stable isotopes and their contribution to sulfur s total abundance on Earth are as follows S-32 contributes 95.02% to the abundance of sulfur S-33, just 0.75% S-34, 4.21% and S-36, 0.02%. 

Sulfur has four stable isotopes with the following abundances (Rosman and Taylor 1998)... 

One of the most sensitive tracers recording the composition of ancient sea water is the isotopic composition of chemical sediments precipitated from sea water. The following discussion concentrates on the stable isotope composition of oxygen, carbon, and sulfur, but in recent years other isotope systems have been included such as Ca (De La Rocha and De Paolo 2000 Schmitt et al. 2003 Fantle and de Paolo 2005 Farkas et al. 2007) and B (Lemarchand et al. 2000, 2002 Joachimski et al. 2005) and Li (Hoefs and Sywall 1997). One of the fundamental questions in all these approaches is which kind of sample provides the necessary information, in the sense that it represents the ocean water composition at its time of formation and has not been modified subsequently by diagenetic reactions. 

Cypionka H, Smock A, BOttcher MA (1998) A combined pathway of sulfur compound disproportionation in Desulfovibrio desulfuricans. FEMS Microbiol Lett 166 181-186 Czamanske GK, Rye RO (1974) Experimentally determined sulfur isotope fractionations between sphalerite and galena in the temperature range 600°C to 275°C. Econ Geol 69 17-25 Dansgaard W (1964) Stable isotope in precipitation. Tellus 16 436 68... 

Hitchon B, Krouse HR (1972) Hydrogeochemistry of the surface waters of the Mackenzie River drainage basin, Canada. III. Stable isotopes of oxygen, carbon and sulfur. Geochim Cosmochim Acta 36 1337-1357... 

McCready RGL (1975) Sulphur isotope fractionation by Desulfovibrio and Desulfotomaculum species. Geochim Cosmochim Acta 39 1395-1401 McCready RGL, Kaplan IR, Din GA (1974) Fractionation of sulfur isotopes by the yeast Saccha-romyces cerevisiae. Geochim Cosmochim Acta 38 1239-1253 McDermott F (2004) Palaeo-cUmate reconstruction from stable isotope variations in speleothems a review. Q Sci Rev 23 901-918... 

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