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How useful is mercury?

Let us now look at the varied uses of mercury. Mercury is used as an electrode in the production of chlorine and sodium hydroxide. It is also used in certain electric batteries.

It is used in barometers and manometers. It is also used extensively in thermometers. Mercury is important as a liquid contact material for electric switches. It was also used in mercury-vapour lamps that were used for street lighting.

Mercury forms a special type of alloy with some metals like silver, and tin. These alloys are used in dentistry for filling teeth. Several compounds of mercury are used as disinfectants.

They are also used to make substances including insecticides and rat poison. Mercuric oxide is used in skin ointments, though of course people handle it with a great deal of care now, because of the danger of mercury poisoning.

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Is mercury a common metal?

Mercury is not a common metal. It is rarely found on Earth’s crust. In fact, it forms only 0.00005 per cent of the crust. However, there are more than 20 minerals that contain mercury. It is found in cinnabar, cordierite, livingstonite and some other minerals, with cinnabar being the most common ore.

Mercury ores usually occur at hot springs or other volcanic regions. Globally, mercury is most commonly produced in Spain; the Almaden mine there is known for its high quality mercury. It is also obtained from the United States and Italy.

Mercury is named after the planet Mercury, which in turn, is named after the Roman God Mercurius, the God of trade, profit and commerce. Mercury is sometimes called quicksilver because of its silver colour. In fact, its chemical symbol ‘Hg’ comes from the Greek word ‘hydrargyrum’ which means ‘water silver’.

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Why were alchemists interested in mercury?

You might already know that alchemy flourished in the Middle Ages when people began going crazy over gold. They also believed that mercury could be converted into gold if they found the philosopher’s stone.

Alchemists would heat mercury with nitric acid to prepare mercuric oxide. The reaction produced a thick red vapour, which hovered over the surface of the solution. The mercuric oxide that was formed would fall to the bottom of the liquid in the form of bright red crystals.

Many of the alchemists used these crystals to fool people about the supposed powers of mercury including the power to grant eternal life. Some alchemists also used mercury to demonstrate that gold could be made artificially.

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Was mercury familiar to our ancestors?

There are evidences that suggest that mercury was known to humans before at least a thousand years. Mercury has been found in Egyptian tombs that date back to 1500 BC. The ancient Chinese and Indians were familiar with the liquid metal. In fact, our ancestors thought of mercury as the first matter from which all metals were formed.

In countries like India, China and Tibet, it was believed that mercury could prolong life, heal fractures, and maintain good health. While the ancient Greeks used mercury in ointments, the Romans used it to make cosmetics.

Our ancestors believed that varying the quality and quantity of sulphur contained within the mercury could produce different metals. They even tried to transform mercury into gold. Needles to say, they were not successful!

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Why should we handle mercury with care?

As already mentioned, mercury was widely used to make ointments, cosmetics and even dental fillings. But studies have revealed that the compounds and vapours of mercury are potentially hazardous as it can cause poisoning.

In fact, mercury poisoning is something to be feared as it does not affect just one part, but each and every system of the human body. It can cause other diseases as well.

Health problems caused by mercury depend on how much of it has entered your body, how it entered your body, how long you have been exposed to it, and how your body responds to mercury. There are many possible ways to get poisoned by mercury.

Some cosmetics can be harmful to us as it contains compounds of mercury. The people working in the paint industry are at risk as paint uses some compounds of mercury. Eating fish that have been exposed to mercury in the environment is also very dangerous.

In 1956, thousands of fishermen and their families in the southern Japanese city of Minamata fell ill because they ate fish that had been contaminated with mercury.

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How useful is lead to us?

We have discussed the harmful effects of lead at length now. But why was lead widely used despite its hazardous impact? Undoubtedly, it was because lead was a useful metal. Let us now look at some of the usages of lead.

In the olden days, lead was used as a building material. It was used as a pigment for glazing ceramics. Water pipes were coated with lead. Today, the most prominent use of lead is to build lead-acid storage batteries. The electrical systems of vehicles, ships, and aircraft depend on such batteries for startup, and in some cases, batteries provide the actual motive power.

Have you heard of sound-proof rooms? Lead is used for soundproofing office buildings, schools, and hotels. It is widely used in hospitals for protection against X-ray and gamma radiation. Lead is also employed as a shield against harmful nuclear radiation.

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