one of the most
important elements on Earth
atomic weight 40.08 amu
boiling point 1,484°
Calcium reacts readily with
both oxygen and water.
Calcium makes up about 3½ per cent of the
Earth's crust, making it the fifth most abundant
element. It is only found in compounds, with calcium chloride, calcium carbonate,
calcium fluoride, and calcium sulfate being the
most common. Pure calcium metal, used in certain
kinds of alloys, is obtained from molten calcium
chloride through a process called electrolysis.
Various industrial processes,
such as leather tanning and petroleum refining,
involve calcium oxide.
Calcium fluoride and calcium
sulfate are used in making cement and plaster for
Manufacturers use other calcium
compounds in a wide variety of products ranging
from fertilizer to paint.
Calcium is essential to all
living things, especially human beings and other
animals. It is vital for the growth and
maintenance of the bones and teeth, and it helps
the blood to clot and the muscles to contract.
Humphry Davy first
isolated calcium as a pure metal in 1808.
However, the ancient Egyptians, Greeks, and
Romans knew about calcium compounds and used them
to make mortar.
The name calcium comes
from calx, or lime (an oxide of
Sir Humphry Davy
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