calcium oxide


: a caustic solid CaO that is white when pure and that is the chief constituent of lime

Examples of calcium oxide in a Sentence

Recent Examples on the Web The leftover calcium oxide, which looks like flour, is then doused with water and spread onto large trays, which are carried by robots onto tower-high racks and exposed to open air. Brad Plumer, New York Times, 9 Nov. 2023 With further study, the researchers concluded that lime clasts arose because of the use of quicklime (calcium oxide) — the most reactive, and dangerous, dry form of limestone — when mixing the concrete, rather than or in addition to slaked lime. Katie Hunt, CNN, 6 Jan. 2023 Its technology uses calcium oxide from limestone, which acts sort of like a sponge to draw carbon dioxide out of the ambient air. Justine Calma, The Verge, 6 Feb. 2023 One of the biggest problems in dealing with carbon dioxide emissions is the making of the key component of cement: lime (calcium oxide). Lloyd Alter, Treehugger, 24 Jan. 2023 Preheated meal is burned in a combustion chamber immediately above and inside the top of the kiln at 750 to 900 degrees C, converting calcium carbonate to calcium oxide (quicklime) and CO2. Mark Fischetti, Scientific American, 13 Jan. 2023 But high amounts of calcium detected on his dagger’s hilt suggest that its artisans used a stronger adhesive instead: lime plaster, composed of sand, water and calcium oxide (lime). Marisa Sloan, Discover Magazine, 4 Nov. 2022 Clinker is made when limestone, calcium carbonate, is taken out of the ground and heated to 2700 to 2800 degrees (1480 to 1540 degrees Celsius) to turn it into calcium oxide. Seth Borenstein, Anchorage Daily News, 23 June 2022 The residue contained sulfur and mercury, as well as magnesium, nitrates, phosphorus, calcium (possibly derived from calcium oxide, a component of Greek fire), lead, and iron. Jennifer Ouellette, Ars Technica, 3 May 2022

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'calcium oxide.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

Word History

First Known Use

1859, in the meaning defined above

Time Traveler
The first known use of calcium oxide was in 1859

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Cite this Entry

“Calcium oxide.” Dictionary, Merriam-Webster, Accessed 20 Apr. 2024.

Kids Definition

calcium oxide

: an oxide of calcium that is white when pure and makes up the major part of lime

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