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| Atomic Number: | 26 | Atomic Symbol: | Fe | | Atomic Weight: | 55.847 | Electron Configuration: | 2-8-14-2 | | Shells: | 2,8,14,2 | Filling Orbital: | 3d6 | | Melting Point: | 1535oC | Boiling Point: | 2750oC | | Uses: | steel and other alloys, tools, essential to human
life |
History(Anglo-Saxon, iron; L. ferrum) Iron was used prehistorically:
- Genesis mentions that Tubal-Cain, seven generations from Adam, was "an
instructor of every artificer in brass and iron."
- A remarkable iron pillar, dating to about A.D. 400, remains standing today
in Delhi, India. This solid shaft of wrought iron is about 7 1/4 m high by 40 cm
in diameter. Corrosion to the pillar has been minimal although it has been
exposed to the weather since its erection.
SourcesIron is a realatively abundant element in the universe. It is
found in the sun and many types of stars in considerable quantity. Its nuclei
are very stable. Iron is a principal component of a meteorite class known as
siderites and is a minor constituent of the other two meteorite classes.
The core of the earth -- 2150 miles in radius -- is thought to be largely
composed of iron with about 10 percent occluded hydrogen. The metal is the
fourth most abundant element, by weight that makes up the crust of the earth.
The most common ore is hematite, which is frequently seen as black sands
along beaches and banks of streams.
IsotopesCommon irons is a mixture of four isotopes. Ten other isotopes
are known to exist.
UsesIron is a vital constituent of plant and animal life and appears in
hemoglobin.
Taconite is becoming increasingly important as a commercial ore. The pure
metal is not often encountered in commerce, but is usually alloyed with carbon
or other metals.
PropertiesThe pure metal is very reactive chemically and rapidly
corrodes, especially in moist air or at elevated temperatures. It has four
allotropic forms or ferrites, known as alpha, beta, gamma, and omega, with
transition points at 700, 928, and 1530C. The alpha form is magnetic, but when
transformed into the beta form, the magnetism disappears although the lattice
remains unchanged. The relations of these forms are peculiar. Pig iron is an
alloy containing about 3 percent carbon with varying amounts of S, Si, Mn, and P.
Iron is hard, brittle, fairly fusible, and is used to produce other alloys,
including steel. Wrought iron contains only a few tenths of a percent of carbon, is tough, malleable, less fusible, and has usually a
"fibrous" structure.
Carbon steel is an alloy of iron with small amounts of Mn, S, P, and Si.
Alloy steels are carbon steels with other additives such as nickel, chromium, vanadium, etc. Iron is a cheap, abundant, useful, and
important metal.
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