iridium

[ ih-rid-ee-uhm, ahy-rid- ]

noun

, Chemistry.

1. a precious metallic element resembling platinum: used in platinum alloys and for the points of gold pens. : Ir; : 192.2; : 77; : 22.4 at 20°C.

iridium

/ ɪˈrɪd-; aɪˈrɪdɪəm /

noun

1. a very hard inert yellowish-white transition element that is the most corrosion-resistant metal known. It occurs in platinum ores and is used as an alloy with platinum. Symbol: Ir; atomic no: 77; atomic wt: 192.22; valency: 3 or 4; relative density: 22.42; melting pt: 2447°C; boiling pt: 4428°C

iridium

/ ĭ-rĭd′ē-əm /

1. A rare, whitish-yellow element that is the most corrosion-resistant metal known. It is very dense, hard, and brittle, and is is used to make hard alloys of platinum for jewelry, pen points, and electrical contacts. Atomic number 77; atomic weight 192.2; melting point 2,410°C; boiling point 4,130°C; specific gravity 22.42 (at 17°C); valence 3, 4.
2. See Periodic Table

Word History and Origins

Origin of iridium¹

1804; < Latin īrid-, stem of īris rainbow ( iris ) + -ium; so named from its iridescence when dissolved in hydrochloric acid

Word History and Origins

Origin of iridium¹

C19: New Latin, from irido- + -ium ; from its colourful appearance when dissolving in certain acids

A Closer Look

In 1978 geologist Walter Alvarez discovered a high concentration of iridium in a layer of clay that had formed between the Mesozoic and Cenozoic eras, a period about 65 million years ago during which dinosaurs and many other organisms became extinct. This finding was significant as iridium is rare at Earth's surface (an unusually high concentration is called an iridium anomaly ). Most surface iridium is thought to come from dust created when meteors disintegrate in the atmosphere or collide with Earth. Alvarez's father, the physicist Luis Alvarez, suggested that the iridium might have come from the impact of a meteor about 10 km (6.2 mi) across. Such an impact would have caused an enormous explosion, sending huge clouds of dust into the atmosphere. The dust, blocking out the Sun and causing extensive acid rain, would have triggered a worldwide ecological disaster. Many scientists think that such a disaster caused the extinction of the dinosaurs and at least 70 percent of all other species alive at the time, including most of Earth's land plants. Geologists have since found iridium deposits in rocks of a similar age in more than 100 places worldwide. Scientists in the early 1990s identified a large impact crater in the Yucatán peninsula of central Mexico that is the same age as the iridium deposit found by Alvarez. It is 200 km (125 mi) wide and may have been caused by the same impact.

Example Sentences

They store all the data they collect, and once they break through the waves, the GPS signal will activate, and it will be able to “phone home” through an iridium satellite network.

From Popular-Science

That firm is Iridium, the satellite telecom valued at more than $5 billion.

From Quartz

Globally distributed iridium layer preserved within the Chicxulub impact structure.

From Nautilus

Presumably the iridium level of a cometary object wouldn’t be that far off, but it remains to be seen.

From Nautilus

Today Iridium is SpaceX’s largest commercial customer, having launched 75 of its satellites on eight SpaceX rockets.

From Fortune

Two years later, a Russian satellite crashed into a communications satellite owned by the company Iridium.

From The Daily Beast

Les Paul was a Monday night regular at the New York City club Iridium for the final years of his life.

From The Daily Beast

Note the quality of the following statements: Iridium has a power, purity and simplicity that pleases me; now I can make progress.

From Project Gutenberg

It has been observed that when Medicinal Iridium acts as a laxative, it will regulate the same.

From Project Gutenberg

It should not be difficult for the physician to fix the status of iridium under this sort of exploitation.

From Project Gutenberg

The native alloy of osmium and iridium does not alloy with gold, however, but falls to the bottom of the molten metal.

From Project Gutenberg

The gold may contain an alloy of osmium and iridium; if so, it should be weighed and treated with aqua regia.

From Project Gutenberg