Wednesday, July 30, 2008

The Elements

All matter in the Universe is made of atoms: tiny particles of different varieties that combine to form all the complicated materials in our bodies, the planet, and outer space.
The different types of atoms (there are 92) are called Elements, and are the subject of a regular column here at Hansisgreat. Many of the elements are familiar: oxygen, aluminum, silver and gold are known to us all. Some of the others are a bit more mysterious, or even virtually unknown.
Today we focus on three which are pretty obscure...

Zirconium:
Atomic Symbol: Zr
Atomic Number: 40
Zirconium is abundant in certain types of stars, called S-type stars. Meteorites contain zirconium, as do samples of rock brought back from the Moon.
Gems that contain zirconium were known in ancient times, and are mentioned in the Bible as hyacinth, jacinth, jargon, and zircon. The element was isolated in 1789 Berlin by Martin Heinrich Klaproth, who discovered uranium the same year. This coincidental link was echoed 150 years later, when both elements were used in the nuclear power industry.
Today it is used to make fake diamonds, often for somewhat gaudy jewelry. It is also used in ultra-strong ceramics. The US Army uses zirconium in tanks engines, not made of metal so they do not need lubrication or cooling systems.

Niobium:
Atomic Symbol: Nb
Atomic Number: 41
Originally named "columbium", after the poetic name for America and the ore from which it was extracted; it was rechristened niobium in 1844, although it is still called columbium in the engineering trade.
Small amounts of niobium impart greater strength to other metals, especially if it is to be welded or exposed to very low temperatures. An alloy with zirconium is particularly resistant to corrosive chemical attack. It is used in surgical implants, because it does not react with human tissue. Jewelry and sculptures made with niobium have a lustrous surface, shimmering with various iridescent colors.

Molybdenum:
Atomic Symbol: Mo
Atomic Number: 42
Although it is essential in trace amounts to all living things, larger does are extremely toxic. Experiments have shown that too much molybdenum causes fetal deformities.
The blades of certain Japanese samurai swords of the fourteenth century contained a surprising amount of molybdenum, giving them added strength and corrosion resistance; yet it was not recognized as a metal until the eighteenth century, and not widely used until the twentieth. Some anonymous Japanese blacksmith must have stumbled upon the benefits of adding molybdenum to iron, but kept the secret to himself so that it died with him.

For my posts on the previous 39 elements, click here.

There's a terrific book of reference on the subject, called Nature's Building Blocks: An A-Z Guide to the Elements, by John Emsley. It's a must read for any chemistry enthusiast.

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