Sulfur atomic weight, variability

Sulfur (Z = 16) has 4 stable isotopes of which is by far the most abundant in nature (95,02%). The others are - - S (0.75%), (4.21%), and (0.02%). These abundances vary somewhat depending on the source of the sulfur, and this prevents the atomic weight of sulfur being quoted for genera use more precisely than 32.066(6) (p. 17), The variability is a valuable geochemical indication of the source of the sulfur and the isotope ratios of sulfur-containing impurities can even be used to identify the probable source of petroleum samples. ... 

Tellurium belongs to group 16 (formerly called VIB) of the periodic table, which also includes oxygen, sulfur, and selenium. Its atomic number is 52, atomic weight 127.6, melting point 449.8°C, and boiling point 989.9°C. Elemental tellurium is a silvery white, metallic, lustrous solid that is quite brittle. Tellurium is known to exist in two allotropic forms the hexagonal crystalline form and an amorphous powder. Chemical properties of tellurium resemble that of selenium and sulfur. However, it is more metallic than these elements. Tellurium exhibits variable valence states from 2- to 6+ the most common ones are 2-, 4+, and 6+. Elemental tellurium is insoluble in water,... 

Coal is a complex mixture of high molecular weight hydrocarbons that are about 85% carbon by mass. It usually contains a relatively small but variable amount of sulfur. The small amount of sulfur can be a significant factor when one considers its potential as a contributor to air pollution and acid precipitation, however. By way of contrast with petroleum, coal has more fused rings of carbon atoms, and the organic structure of coal is much more complicated. 

---