Mercury - Hg

What are the origins of the word Mercury?
Mercury was named after the Roman god Mercury. Its chemical symbol (Hg) is derived from hydrargyrum from the Greek word hydrargyros meaning 'water' and 'silver'.

Mercury occurs in the environment usually as mercuric sulphide, (Cinnabar).  There are records of Cinnabar being refined for its mercury content dating from around the 16th century.  However the is some proof that mercury was known to the ancient Egyptians.

Mercury is classified as a "Transition Metal" which means it belongs to the group of metals which are ductile, malleable, and conduct electricity and heat.
Mercury is a cumulative poison which is found in our soil, water and food supply, as well as fungicides and pesticides.  Large and predatory fish have been found to be particularly susceptible to mercury accumulation.

Cumulative - means something being increased or enlarged by successive additions being made

Toxic - pertaining to poison; poisonous

Elemental - relating to or being an element: "elemental mercury"

Ductile – used to describe metals that can be bent easily

Malleable – used to describe a substance that is easily changed into a new shape

Common Uses of Mercury

Chemical pesticides
Fluorescent/vapour lighting

Where else can it be found?
Dental fillings
Fabric softeners
Printer and tattoo ink
Wood preservatives
Some medications

It is a heavy, silvery white metal, a rather poor conductor of heat, as compared with other metals, a fair conductor of electricity. It easily forms alloys with mercury metals, such as gold, silver and time which are called amalgams. The metal is widely used in laboratory work for making thermometers, barometers, diffusion ion pumps any many other instruments. Mercury should be handled with care because of the absorbing throught he skin and can cause many skin problems.

Minamata Disaster

Mercury levels can magnify up to 100,000 times in predatory fish. In the 1950s, the consumption of fish which had been contaminated by methyl mercury led to the poisoning of thousands of fishing families in Minimata, Japan, over 10,000 people.

Methyl mercury was released in the industrial wastewater from the Chisso Corporations’ factory into Minamata Bay and the Shiranui Sea and took place over 3 decades, from around 1932 to 1968.   Whilst the increasing number of deaths amongst cats, dogs and pigs as well as the human population the government and Chisso Corporation took little or no steps to stop the pollution.
Symptoms of Minamata disease include ataxia, numbness of the hands and feet, impaired speech, hearing and sight and muscle weakness.  A congenital form of the disease was found to affect unborn fetuses.  In some extreme cases insanity, paralysis, coma and then death followed within weeks of the first onset of the disease.

A second outbreak of Minamata disease occurred in Niigata Prefecture in 1965. Both of these outbreaks of Minamata disease are found in the listing of the four Big Pollution Diseases of Japan.
For more information on the disaster visit

The Mad Hatter

This character of the Mad Hatter in Lewis Carroll’s Alice in Wonderland got his name from the phrase "Mad as a hatter," which was popular during the 1830s. This phrase came about because ‘hatters’ really did go mad.

Mercurous nitrate was used in the making of hats and continuous exposure to the mercury vapor affected the nervous systems of the hatters, caused them to develop severe and uncontrollable muscular tremors and twitching limbs, referred to as "hatter's shakes."  Other symptoms included visual and speech impairment and even hallucinations.

It is a liquid metal that is not wet

It can be used to make mirrors

Stays at room temperature, which is why it is used in thermometers

Bricks, cannonballs and lumps of lead or iron will float on mercury but gold will not, it will act like sugar in tea and dissolves

Mercury does not stick to magnets

Dry ice will help get rid of spilt mercury

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Isolation: the physical appearance of mercury is well known because of its use in many thermometers. It was common to demonstrate the formation of mercury in the laboratory by heating mercury sulphide (cinnabar, HgS) but this is strongly discouraged today because of the toxcity of mercury vapours. Don't do it! However, thismethod forms the basis of commercial extraction. The prepared cinnabar ore is heated in a current of air and the mercury vapour condensated.

HgS + O2 (600°C) > Hg (l) + SO2 (g)

The crude mercury is then washed with nitric acid and treated with air in order to remove impurities as oxides or into solution further purification is achieved by distillation at reduced pressure.

Organic mercury compounds are important - and dangerous. Methylmercury is a lethal pollutant found in rivers and lakes. The main source of pollution is industrial wastes settling to the river and lake bottoms.

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