carbon 12

American  

Also carbon-12

noun

1. the isotopic carbon atom that comprises 99 percent of naturally occurring carbon, and that since 1961 has been used as the standard for atomic weight by representing a unit of 12.00000.

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carbon 12 Scientific  

1. A stable isotope of carbon, having six protons and six neutrons in the nucleus. Carbon 12 makes up most naturally occurring carbon.

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Etymology

Origin of carbon 12

First recorded in 1940–45

Compare meaning

How does carbon-12 compare to similar and commonly confused words? Explore the most common comparisons:

• carbon 12 vs. carbon 14

Example Sentences

See Examples For:

carbon 12

The vast majority of the carbon in the atmosphere is carbon 12, a stable atom with six protons and six neutrons.

From Seattle Times ● Oct. 21, 2021

In 1953 Hoyle's investigations of how stars generate heavy elements led him to predict the existence of a previously unknown state of the isotope carbon 12.

From Scientific American ● Apr. 11, 2020

Carbon 13 usually comes from inorganic sources, such as volcanoes, while carbon 12 is tied to living things.

From Washington Times ● Jun. 11, 2017

The element carbon usually has six protons and six neutrons, and when it does it is called carbon 12.

From Forbes ● May 21, 2010

The amount of carbon 12 stays the same, but the unstable carbon 14 begins to disintegrate.

From Time Magazine Archive