Symbol S. A yellow non-metallic element belonging to group 16
(formerly VIB) of the periodic table. a.n.16; r.a.m.32.06. r.d. 2.07
(rhombic); m.p. 112.8°C. b.p.444.614°C.
element occurs in many sulphide and sulphate minerals and native
sulphur is also found in Sicily and the USA (obtained through the
Frasch process). It can also be obtained from hydrogen sulphide by
the Claus process.
Sulphur has various allotropic forms. Below 95.6°C the stable
crystal form is rhombic: above this temperature the element
transforms into a triclinic form. These crystalline forms both
contain S8 molecules, At temperatures just above the
melting point, molten sulphur is a yellow liquid containing S8
rings (as in the solid form). At about 160°C the sulphur atoms form
chains and the liquid becomes viscous and dark brown. If the molten
sulphur is cooled quickly from this temperature (e.g. by pouring
into cold water) a reddish brown solid known as plastic sulphur is
obtained. Above 200°C the viscosity decreases. Sulphur vapour
contains a mixture of S2 S4 S6 and
element is also used to produce sulphuric acids and other sulphur
Flowers of sulphur
is a yellow powder obtained by subliming the vapour (sublimation: a
direct change of state from solid to gas to solid). It is used in a
range of products from
garden fungicides to dandruff control shampoos, in pharmaceutical,
agricultural, horticultural, animal health and homeopathy industries.
Sulphur is an essential element in living organisms and
sulphur is absorbed by plants from the soil as the sulphate (SO42-).
Essential elements are those elements required by living organisms
to ensure normal growth, development and maintenance. Apart from the
elements found in organic compounds (i.e. carbon, hydrogen, oxygen,
and nitrogen) plants, animals and micro-organisms all require a
range of elements in varying amounts depending on the type of
organism. The major elements present in the tissues in
relatively large amounts (greater than 0.005%) are calcium,
phosphorus, potassium, sodium, chlorine, sulphur and magnesium.
Trace elements occur at much lower concentrations and thus
requirements are much less. The most important are iron, manganese,
zinc, copper, iodine, cobalt, selenium, chromium and silicon. Each
element may fulfil one or more of a
variety of metabolic roles.
16 is a group of elements in the periodic table: oxygen (O) sulphur
(S) selenium (Se) tellurium (Te) and polonium (Po), which all have
outer electron configurations ns2np4 with no
partly filled inner levels. They are also called the chalcogens.
(Formerly they were classified in group VI which consisted of
subgroups VIA and VIB).
the cycling of sulphur between the biotic (living) and the abiotic
(nonliving) components of the environment. Most of the sulphur in
the abiotic environment is found in rocks, although a small amount
is present in the atmosphere as sulphur dioxide (SO2)
produced by combustion of fossil fuels. Sulphates (SO42-)
derived from the weathering and oxidation of rocks is taken up by
plants and incorporated into sulphur containing proteins and passed
along the food chain to animals, Decomposition of dead organic
matter by anaerobic sulphate reducing bacteria returns sulphur to
the abiotic environment in the form of hydrogen sulphide (H2S).
Hydrogen sulphide can be converted back to sulphate or to elemental
sulphur by the action of different groups of photosynthetic and
sulphur- reducing bacteria. Elemental sulphur becomes incorporated
a salt or ester of sulphur (VI) acid. Organic sulphates have the
formula R2SO4 where R is the organic group.
Sulphate salts contain the ion SO42-.
a salt or ester derived from sulphurous acid. The salts contain the
ion SO32-. Sulphites generally have reducing
Inorganic compounds of sulphur with more electropositive elements.
Compounds of sulphur with non metals are covalent compounds – e.g.
hydrogen sulphide H2S
Organic compounds that contain the group – S – linked to two
Sulphur is found in group 16 of the periodic table . It exhibits
allotropy . Solid sulphur occurs principally in three forms, all of
which are brittle, yellow in colour, odourless, tasteless, and
insoluble in water. Two of these solid forms are crystalline,
composed of molecules containing eight sulphur atoms and having
molecular weight 256.512 amu. Rhombic sulphur has orthorhombic
crystalline structure and is stable below 95.5°C; most sulphur is in
this form. The monoclinic, or prismatic, form has long, needle-like,
nearly transparent crystals; it is stable between 95.5°C and its
melting point but reverts to the rhombic form on standing at room
temperature. Amorphous sulphur is a dark, non-crystalline, gum-like
substance. It is often thought to be a super-cooled liquid. It is
formed by rapidly cooling molten sulphur, e.g., by pouring it into
cold water. It slowly reverts to the rhombic form on standing.
Sulphur , non-metallic chemical element; symbol S; at. no. 16; at.
wt. 32.06; m.p. 112.8°C (rhombic), 119.0°C (monoclinic), about 120°C
(amorphous); b.p. 444.674°C; sp. gr. at 20°C, 2.07 (rhombic), 1.957
(monoclinic), 1.92 (amorphous);
Even more about sulphur:
The following is a very useful round up of
various online definitions of sulphur and its uses