boron

American  

[bawr-on, bohr-] / ˈbɔr ɒn, ˈboʊr- /

noun

Chemistry.

1. a nonmetallic element occurring naturally only in combination, as in borax or boric acid, and obtained in either an amorphous or a crystalline form when reduced from its compounds. B; 10.811; 5.

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boron British  

/ ˈbɔːrɒn /

noun

1. a very hard almost colourless crystalline metalloid element that in impure form exists as a brown amorphous powder. It occurs principally in borax and is used in hardening steel. The naturally occurring isotope boron-10 is used in nuclear control rods and neutron detection instruments. Symbol: B; atomic no: 5; atomic wt: 10.81; valency: 3; relative density: 2.34 (crystalline), 2.37 (amorphous); melting pt: 2092°C; boiling pt: 4002°C

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boron Scientific  

/ bôr′ŏn′ /

1. A shiny, brittle, black metalloid element extracted chiefly from borax. It is a good electrical conductor at high temperatures and a poor conductor at low temperatures. Boron is necessary for the growth of land plants and is used in the preparation of soaps, abrasives, and hard alloys. It is also used in the control rods of nuclear reactors as a neutron absorber. Atomic number 5; atomic weight 10.811; melting point 2,300°C; sublimation point 2,550°C; specific gravity (crystal) 2.34; valence 3.

2. See Periodic Table

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Other Word Forms

• boronic
  adjective

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Etymology

Origin of boron

1805–15; bor(ax ¹ ) + (carb)on

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Example Sentences

See Examples For:

boron

In particular, traces of boron could absorb neutrons that would otherwise help sustain the reaction, preventing the reactor from reaching criticality.

From Science Daily ● Oct. 16, 2026

Materials such as boron arsenide may allow engineers to direct heat along planned routes with nanoscale accuracy instead of waiting for it to spread and then trying to remove it.

From Science Daily ● Aug. 7, 2026

Titan Mining, EnergyX, Ioneer, and REalloys received leases to process graphite, lithium, boron, and rare earth elements.

From The Wall Street Journal ● Jun. 25, 2026

Plans are underway for a new lithium and boron mine at Rhyolite Ridge, approximately 30 miles southwest of Tonopah, in Nevada’s Silver Peak Range.

From Los Angeles Times ● Jun. 14, 2026

The result of their bombardments of boron and other light elements by alpha rays, moreover, had led them to propose that the proton was composed of a neutron and a positive electron, or positron.

From "Big Science" by Michael Hiltzik

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