Sulfur solar abundance

Natural isotopes of sulfur and their solar abundances... 

The agreement between meteoritic and solar abundances must be considered excellent and there is not much room left for further improvements. Obvious candidates for redetermination of the solar abundances are manganese and sulfur. 

The abundances of 39 nongaseous elements in the Sun have assigned errors below 30%. Only the four elements sulfur, manganese, scandium, and strontium differ by more than 20% from Cl abundances. The difference is below 10% for 27 of these elements. The agreement between meteoritic and solar abundances must therefore be considered excellent and there is not much room left for further improvements. Obvious candidates for redetermination of solar abundances are manganese and sulfur. The hmiting factor in the accuracy of meteorite abundances is the inherent variability of Cl chondrites, primarily the Orgueil meteorite. 

As can be seen in Fig. 2-1 (abundance of elements), hydrogen and oxygen (along with carbon, magnesium, silicon, sulfur, and iron) are particularly abundant in the solar system, probably because the common isotopic forms of the latter six elements have nuclear masses that are multiples of the helium (He) nucleus. Oxygen is present in the Earth s crust in an abundance that exceeds the amount required to form oxides of silicon, sulfur, and iron in the crust the excess oxygen occurs mostly as the volatiles CO2 and H2O. The CO2 now resides primarily in carbonate rocks whereas the H2O is almost all in the oceans. 

Among the elements that make up rocks and minerals, silicon, magnesium, and iron are of almost equal abundance followed by sulfur, aluminum, calcium, sodium, nickel, and chromium. Two of the most common minerals in meteorites and in the terrestrial planets are olivine ((Mg,Fe)2Si04) and pyroxene ((Mg,Fe,Ca)Si03). The composition obtained by averaging these two minerals is very similar to the bulk solar system composition, so it is really no surprise that they are so abundant. 

From the isotopic decomposition of normal sulfur one finds that the mass-32 isotope, 32S, is the most abundant of the stable S isotopes 95.02% of all S. On the scale where one million silicon atoms is taken as the standard for solar-system matter, this isotope has... 

Solar Hydrogen Production Using Water and Abundant Sulfur Compounds on Metal Sulfide Photocatalysts... 

In Figure 3, sodium, zinc, and sulfur are representative of the abundances of moderately volatile elements (Figure 2 and Table 2). Abundance variations reach a factor of 5 for sulfur and 10 for zinc. All three elements show excellent agreement of solar with Cl abundances, in contrast to other groups of chondritic meteorites, except for the enstatite chondrites, which reach the level of Cl abundances. However, enstatite chondrites... 

Based on the bulk chemistry, IDPs are divided into two groups (i) micrometer-sized chondritic particles and (ii) micrometer-sized nonchondritic particles. A particle is defined as chondritic when magnesium, aluminum, silicon, sulfur, calcium, titanium, chromium, manganese, iron, and nickel occur in relative proportions similar (within a factor of 2) to their solar element abundances, as represented by the Cl carbonaceous chondrite composition (Brownlee et al., 1976). Chondritic IDPs differ significantly in form and texture from the components of known carbonaceous chondrite groups and are highly enriched in carbon relative to the most carbon-rich Cl carbonaceous chondrites (Rietmeijer, 1992 Thomas et al., 1996 Rietmeijer, 1998, 2002). 

H2O, CO, OCS, and SO have spatially and temporally variable abundances. Variations in the abundances of water vapor, CO, and sulfur gases are of particular interest because they result from the solar UV-diiven photochemistry that maintains the global sulfuric acid cloud cover. 

It therefore comes as no great surprise that within our solar system itself, all 11 of the principal elements found in man are in the top 20 in terms of abundance, with five of them figuring in the top ten — hydrogen, carbon, nitrogen, oxygen, and sulfur. When we consider the abundance of these 11 obviously essential elements in the earth s crust (Fig. 1.2), we find that no less than six of them (hydrogen, oxygen, and the four alkali and alkaline... 

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