sulfur

Name sulfur
Symbol S
Atomic Weight 32.065
Atomic Number 16
CAS ID 7704-34-9
Group Number 16
Group Name Chalcogen
Period Number 3
Origin of Name Sanskrit, sulvere = "sulfur;" Latin sulphurium.
Year Discovered Prehistoric
Discovery Credits Known to ancient civilizations.
Class Non-Metallic
Color Yellow
Standard State Solid at 77 F & 298 K
Description Several allotropes, of which orthorhombic S8 is the most stable. Stable to air and water but burns if heated. Attacked by oxidizing acids. Recovered from H2S in natural gas or from salt domes by the Frasch process. Key industrial chemical.

Diagnostic tests: 
Native Sulfur (S0): Native sulfur can be detected by the faint odor of sulfur dioxide (SO2) gas from the sample.
Sulfides (S2-): In the closed tube, some sulfides give off sulfur when heated. In the open tube, they yield sharp smelling sulfur dioxide (SO2) gas.
Sulfates (SO42-): Fuse a sample on charcoal mixed with with soda (Na2CO3) and charcoal dust. The fused mass, when sodium sulfide has thus been formed, is place on a clean silver coin or other object and moistened, a distinct black stain on the silver is thus obtained. In an acid (HCl) solution, SO42- gives a white precipitate by the addition of dilute BaCl2.

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