Iridium Facts

Iridium Facts
Iridium (Ir) has an atomic number of seventy-seven. It is a yellowish-white member of the platinum metals group, but its salts are very colorful.
Interesting Iridium Facts:
Iridium's discovery has an origin very similar to that of osmium.
Scientists dissolved platinum in aqua regia, only to find a dark residue that resembled graphite.
Smithson Tennant discovered the residue to contain osmium and iridium in 1803.
He published his work and officially named both elements in 1804.
It wasn't until 1842 that a scientist, Robert Hare, was able to obtain a sample of pure iridium.
Rudolf Mossbauer won the Nobel Prize for Physics for the discovery of what is known as the Mossbauer Effect, often called one of the greatest physics experiments of the 20th century.
In this experiment, Mossbauer discovered iridium's gamma ray absorptions properties and led to the technique of Mossbauer spectroscopy.
Iridium is one of the rarest elements in the Earth's crust.
It is believed to be available at 0.001 parts per million.
Gold, silver, mercury, and platinum are all exonentially more abundant than iridium.
Iridium is more prevalent in meteorites, and 0.05 parts per million or higher.
The largest meteorite ever to land in North America, the Willamette Meteorite, contains a comparably vast concentration of iridium, at 4.7 parts per million.
Like osmium, iridium concentrations are highest in a few known geological structures, most notably impact craters from meteorites.
Iridium was responsible for the Alvarez Hypothesis, that a massive object collided with the Earth, causing the extinction of most species 65 million years ago.
At the time that the event would have taken place, the geological record shows an unusually high level of iridium in the planet's clay layer.
One theory about iridium's low abundance is that its high density and siderophilic properties caused it to sink below the Earth's crust while the planet was still primarily molten.
Iridium has two stable isotopes, both of which are found naturally.
There are also around thirty-four produced radioactive isotopes of iridium.
Due to difficulty in extracting iridium, there are not many industrial applications for the element.
Most applications of iridium tend to be alloys, since the metal is highly corrosion-resistant at high temperatures.
Demand for iridium quintupled from 2009 to 2010, due to the rise of iridium use in electronics and the growth of high-quality crystals.

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