Sulphur is also known as sulfur. Sulphur is a multivalent non-metal, abundant, tasteless and and odorless. In its native form sulphur is a yellow crystalline solid. In nature it occurs as the pure element or as sulfide and sulfate minerals. Although sulphur is infamous for its smell, frequently compare to rotten eggs, that odor is actually characteristic of hydrogen sulphide (H2S). The crystallography of sulphur is complex. Depending on the specific conditions, sulphur allotropes form several distinct crystal structures.
Sulphur (sulfur) is a pale yellow, odourless, brittle solid, which is insoluble in water but soluble in carbon disulphide. Sulphur is essential to life. It is a minor constituent of fats, body fluids, and skeletal minerals. The spelling of sulphur is "sulfur" in the USA while sulphur is common elsewhere. IUPAC has does not have jurisdiction over language but has decided sulfur is preferred. Sulphur is found in meteorites, volcanoes, hot springs, and as galena, gypsum, Epsom salts, and barite. It is recovered commercially from "salt domes" along the Gulf Coast of the USA.
Jupiter's moon Io owes its colours to various forms of sulphur. A dark area near the crater Aristarchus on the moon may be a sulphur deposit. Carbon disulphide, hydrogen sulphide, and sulphur dioxide should be handled extremely carefully. Hydrogen sulphide in very small concentrations can be metabolized, but in higher concentrations it can cause death quickly by respiratory paralysis. It is insidious in that it quickly deadens the sense of smell. Sulphur dioxide is a dangerous component in atmospheric air pollution and is one of the factors responsible for acid rain.
*Atomic number-16
*Atomic mass-32.06 g.mol -1
*Electronegativity according to Pauling-2.5
*Density-2.07 g.cm -3 at 20 °C
*Melting point- 113 °C
*Boiling point-445 °C
Charasterstics:
*Sulfur is a soft, pale yellow, odorless, brittle solid. It is insoluble in water, but soluble in carbon disulfide. It burns with a blue flame, oxidizing to sulfur dioxide.
*Sulfur exists in several crystalline and amorphous allotropes. The most common form is yellow, orthorhombic alpha-sulfur, which contains puckered rings of S8.
*Sulfur is multivalent and combines, with valence 2, 4, or 6, with almost all other elements. The best known sulfur compound is hydrogen sulfide (H2S). This is a toxic gas that smells like rotten eggs; the smell is used in stink bombs, many of which release a small amount of hydrogen sulfide.
Sulphur in the Environment:
Life on Earth may have been possible because of sulphur. Conditions in the early seas were such that simple chemical reactions could have generate the range of amino acids that are the building blocks of life.
Sulphur occurs naturally near volcanoes. Native sulphur occurs naturally as massive deposits in Texas and Louisiana in the USA. Many sulphide minerals are known: pyrite and marcaiste are iron sulphide ; stibnite is antimony sulphide; galena is lead sulphide; cinnabar is mercury sulphide and sphalerite is zinc sulphide. Other, more important, sulphide ores are chalcopyrite, bornite, penlandite, millerite and molybdenite.
The chief source of sulphur for industry is the hydrogen sulphide of natural gas, Canada is the main producer.
Physical Properties:
The main physical properties of sulphur are:
1. Sulphur usually occurs as a pale yellow, brittle, crystalline solid.
2. It has a faint characteristic smell, but no taste.
3. Sulphur is insoluble in water; it is not ever wetted by it. If a pinch of powdered sulphur is dropped into water, the particles will not sink but spread on the surface to form a yellow film.
4. Sulphur is highly soluble in carbon disulphide and sparingly soluble alcohol and ether.
5. It has a low melting point (114`C).
6. It occurs in a number of allotropic forms a two of which, the rhombic an d monoclinic, are crystalline.
Chemical Properties:
Sulfur burns with a blue flame concomitant with formation of sulfur dioxide, notable for its peculiar suffocating odor. Sulfur is insoluble in water but soluble in carbon disulfide and, to a lesser extent, in other nonpolar organic solvents, such as benzene and toluene. The first and the second ionization energies of sulfur are 999.6 and 2252 kJ·mol−1, respectively. Despite such figures, the +2 oxidation state is rare, with +4 and +6 being more common. The fourth and sixth ionization energies are 4556 and 8495.8 kJ·mol−1, the magnitude of the figures caused by electron transfer between orbitals; these states are only stable with strong oxidants as fluorine, oxygen, and chlorine.
Reactions:
Reaction with air:vigorous, w/ht ⇒ SO2 Reaction with 6 M HCl: none
Reaction with 15 M HNO3:vigorous, ⇒ H2SO4, NOx Reaction with 6 M NaOH: none
Health Effects of Sulphur:
Elemental sulphur is not toxic, but many simple sulphur derivates are, such as sulphur dioxide (SO2) and hydrogen sulfide.
Sulfur can be found commonly in nature as sulphides. During several processes sulfur bonds are added to the environment that are damaging to animals, as well as humans. These damaging sulphur bonds are also shaped in nature during various reactions, mostly when substances that are not naturally present have already been added. They are unwanted because of their unpleasant smells and are often highly toxic.
Globally sulphuric substances can have the following effects on human health:
- Neurological effects and behavioural changes
- Disturbance of blood circulation
- Heart damage
- Effects on eyes and eyesight
- Reproductive failure
- Damage to immune systems
- Stomach and gastrointestinal disorder
- Damage to liver and kidney functions
- Hearing defects
- Disturbance of the hormonal metabolism
- Dermatological effects
- Suffocation and lung embolism
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