This article needs additional citations for verification. Please help improve this articlebyadding citations to reliable sources. Unsourced material may be challenged and removed.
Find sources: "Calx" – news · newspapers · books · scholar · JSTOR (September 2018) (Learn how and when to remove this message) |
Calx is a substance formed from an ore or mineral that has been heated.[1] Calx, especially of a metal, is now understood to be an oxide. The term is also sometimes used in older texts on artists' techniques to mean calcium oxide. [citation needed]
According to the obsolete phlogiston theory, the calx was the true elemental substance that was left after phlogiston was driven out of it in the process of combustion.[2]
Calx is Latin for chalkorlimestone, from the Greek χάλιξ (khaliks, “pebble”). (It is not to be confused with the Latin homonym meaning heelbone (orcalcaneus in modern medical Latin), which has an entirely separate derivation.)
In the early 18th century Georg Stahl renamed the substance phlogiston (from the Greek for 'burned') and extended the theory to include the calcination (and corrosion) of metals. Thus, metals were thought to be composed of calx (a powdery residue) and phlogiston; when a metal was heated, phlogiston was set free and the calx remained. The process could be reversed by heating the metal over charcoal (a substance believed to be rich in phlogiston, because combustion almost totally consumed it). The calx would absorb the phlogiston released by the burning charcoal and become metallic again.
 | This inorganic compound–related article is a stub. You can help Wikipedia by expanding it. |