Nomenclature
CAS number: 7704-34-9
Brimstone; sulphur.
Description and references
S; at. wt 32.066; at. no. 16; valences 2, 4,
6. Group VIA (16). Four naturally occurring isotopes: 32 (95.0%);
33 (0.76%); 34 (4.22%); 36 (0.014%); artificial, radioactive isotopes:
29-31; 35; 37; 38. Has been known from very early times. Occurs
both in the free state and in combination, mainly as sulfides and
sulfates; constitutes 0.05% of the crust of the earth. Industrial
prepn by Frasch process: Faith, Keyes &
Clark's Industrial Chemicals, F. A. Lowenheim, M. K. Moran,
Eds. (Wiley-Interscience, New York, 4th ed., 1975) pp 786-794. Exists
in several allotropic modifications; at S.T.P. only the orthorhombic,
cyclooctasulfur (Sα) is thermodynamically stable: Meyer, Chem. Rev. 64, 429 (1964). Prepn
of cyclohexasulfur: Bartlett et al., J. Am. Chem. Soc. 83, 10 (1961); of cyclohepta-
and cyclodecasulfur: Schmidt et al., Angew. Chem. Int. Ed. 7, 632 (1968); of cyclononasulfur:
Schmidt, Wilhelm, Chem. Commun. 1970, 1111; of cyclododecasulfur: eidem, Angew. Chem. Int. Ed. 5, 964 (1966).
Review of structures of elemental sulfur: Meyer in Adv. Inorg. Chem. Radiochem. 18, 287-317 (1976). Reviews of sulfur and its compds: W. N. Tuller, The Sulphur Data Book (McGraw-Hill, New York,
1954); B. Meyer, Elemental Sulfur (Interscience-Wiley, 1965); Inorganic Sulphur
Chemistry, G. Nickless, Ed. (Elsevier, New York, 1968);
Schmidt, Siebert in Comprehensive Inorganic
Chemistry vol. 2, J. C. Bailar, Jr. et
al., Eds. (Pergamon, Oxford, 1973) pp 795-933. See also Sulfur, Pharmaceutical.
Properties
Yellow solid. Insol in water. Sparingly sol
in alcohol, in ether; sol in carbon disulfide (one gram/2 ml); sol
in benzene (about 2.4% at 30°, much more at higher temps.), in toluene.
Liquid ammonia (anhydr) dissolves 38.5% S at 78°; acetone dissolves
2.65% at 25°; methylene iodide dissolves 9.1% at 10°; chloroform dissolves
about 1.5% at 18°. For other solvents see Tuller, op. cit. Flammable. Ignites
in air above 261°, in oxygen below 260°, burning to the dioxide; combines
readily with hydrogen; combines in the cold with fluorine, chlorine,
and bromine; combines with carbon at high temperatures; reacts with
silicon, phosphorus, arsenic, antimony and bismuth at their melting
points; combines with nearly all metals; with lithium, sodium, potassium,
copper, mercury and silver in the cold on contact with the solid;
with magnesium, zinc and cadmium very slightly in the cold, more readily
on heating; with other metals at high temperatures. Does not react
with iodine, nitrogen, tellurium, gold, platinum and iridium.Derivative
α-Sulfur.
Properties
Orthorhombic cyclooctasulfur. Amber-colored crystals;
the stable form at ordinary temperature. d 2.06; when heated to 94.5° becomes opaque
owing to the formation of monoclinic sulfur.Derivative
β-Sulfur.
Properties
Monoclinic cyclooctasulfur. Opaque, light-yellow,
brittle, needle-like crystals; stable between 94.5-120°. Passes slowly
into the rhombic form on standing. d 1.96; mp 115.21°: West, J. Am. Chem. Soc. 81, 29 (1959). bp ≈444.6°.Derivative
γ-Sulfur.
Nomenclature
Mother-of-pearl sulfur. Properties
A second monoclinic form, mp 106.8°.Derivative
Polymeric sulfur.
Properties
Amorphous form; mol wt approx 200,000. Metastable,
gradually reverts to the α-form. Insol in solvents used for orthorhombic
form. Reviews: Meyer, loc. cit. (1964); A. V. Tobolsky, W. J. MacKnight, Polymeric Sulfur and Related Polymers (Interscience,
New York, 1965) pp 87-97.Caution
May cause irritation of skin, mucous
membranes.Use
In mfg sulfuric acid, carbon disulfide, sulfites,
insecticides, plastics, enamels, metal-glass cements; in vulcanizing
rubber; in syntheses of dyes; in making gunpowder, matches; for bleaching
wood pulp, straw, wool, silk, felt, linen.