phlogiston

/floh jis"ton, -teuhn/, n.
a nonexistent chemical that, prior to the discovery of oxygen, was thought to be released during combustion.
[1720-30; < NL: inflammability, n. use of Gk phlogistón, neut. of phlogistós inflammable, burnt up; see PHLOGISTIC]

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▪ chemical theory
      in early chemical theory, hypothetical principle of fire, of which every combustible substance was in part composed. In this view, the phenomena of burning, now called oxidation, was caused by the liberation of phlogiston, with the dephlogisticated substance left as an ash or residue.

      Johann Joachim Becher (Becher, Johann Joachim) in 1669 set forth his view that substances contained three kinds of earth, which he called the vitrifiable, the mercurial, and the combustible. He supposed that, when a substance burned, combustible earth (Latin terra pinguis, meaning “fat earth”) was liberated. Thus, wood was a combination of phlogiston and wood ashes. To this hypothetical substance Georg Ernst Stahl (Stahl, Georg Ernst), at about the beginning of the 18th century, applied the name phlogiston (from Greek, meaning “burned”). Stahl believed that the corrosion of metals in air (e.g., the rusting of iron) was also a form of combustion, so that when a metal was converted to its calx, or metallic ash (its oxide, in modern terms), phlogiston was lost. Therefore, metals were composed of calx and phlogiston. The function of air was merely to carry away the liberated phlogiston.

      The major objection to the theory, that the ash of organic substances weighed less than the original while the calx was heavier than the metal, was of little significance to Stahl, who thought of phlogiston as an immaterial “principle” rather than as an actual substance. As chemistry advanced, phlogiston was considered a true substance, and much effort was expended in accounting for the weight changes observed. When hydrogen, very light in weight and extremely flammable, was discovered, some thought it was pure phlogiston.

      The phlogiston theory was discredited by Antoine Lavoisier (Lavoisier, Antoine-Laurent) between 1770 and 1790. He studied the gain or loss of weight when tin, lead, phosphorus, and sulfur underwent reactions of oxidation or reduction (deoxidation); and he showed that the newly discovered element oxygen was always involved. Although a number of chemists—notably Joseph Priestley, one of the discoverers of oxygen—tried to retain some form of the phlogiston theory, by 1800 practically every chemist recognized the correctness of Lavoisier's oxygen theory.

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Universalium. 2010.

Look at other dictionaries:

  • Phlogiston — (von griech. φλογιστός phlogistós „verbrannt“) oder Caloricum ist eine hypothetische Substanz, von der man im späten 17. und 18. Jahrhundert vermutete, dass sie allen brennbaren Körpern bei der Verbrennung entweicht sowie bei Erwärmung in… …   Deutsch Wikipedia

  • Phlogiston — Phlo*gis ton, n. [NL., fr. Gr. ? burnt, set on fire, fr. ? to set on fire, to burn, fr. ?, ?, a flame, blaze. See {Phlox}.] (Old Chem.) The hypothetical principle of fire, or inflammability, regarded by Stahl as a chemical element. [1913 Webster] …   The Collaborative International Dictionary of English

  • phlogiston — 1730, hypothetical inflammatory principle, formerly believed to exist in all combustible matter, from Modern Latin (1702), from Gk. phlogiston (1610s in this sense), neut. of phlogistos burnt up, inflammable, from phlogizein to set on fire, burn …   Etymology dictionary

  • Phlogiston — (gr.), wurde zuerst von G. E. Stahl als eigener Grundstoff der Körper, worauf zunächst die Fähigkeit zu brennen beruhe, aufgestellt. Obgleich nur Hypothese, wurde das P. doch eine Zeitlang eine der Hauptgrundlagen der Chemie, bis nach Entdeckung… …   Pierer's Universal-Lexikon

  • Phlógiston — (griech.), nach der Theorie von Stahl (1660–1734) und seinen Anhängern (den Phlogistikern) der hypothetische Bestandteil der brennbaren Körper (auch der Metalle), der bei der Verbrennung oder Oxydation entweicht. Weiteres s. Chemie, S. 913 …   Meyers Großes Konversations-Lexikon

  • Phlogiston — Phlogĭston (grch.), Brennstoff, nach der Verbrennungstheorie von G. E. Stahl (s.d.) der hypothetische Stoff, der bei der Verbrennung der Körper entweichen sollte. Diese phlogistische Theorie wurde durch Lavoisier widerlegt; die Entwicklungsstufe… …   Kleines Konversations-Lexikon

  • Phlogiston — Phlogiston, griech., in Stahls (s.d.) Chemie der Brennstoff in einem Körper; phlogistisch, brennbar; phlogistisiren, mit Brennstoff verbinden …   Herders Conversations-Lexikon

  • phlogiston — [flō jis′tän, flō jis′tən] n. [ModL < Gr phlogistos < phlogizein, to burn, inflame < phlegein, to burn: for IE base see BLACK] an imaginary element formerly believed to cause combustion and to be given off by anything burning; matter or… …   English World dictionary

  • Phlogiston — Phlogistique La théorie du phlogistique est une théorie scientifique obsolète concernant la combustion. Elle a été développée par J.J. Becher à la fin du XVIIe siècle et fut prolongée et développée par Georg Ernst Stahl. La théorie… …   Wikipédia en Français

  • Phlogiston — Phlo|gis|ton [griech. phlogistón = Verbranntes; ↑ on (2)], das; s: haupts. im 18. Jahrhundert Bez. für eine – in reiner Form unfassbare – Substanz, die in allen brennbaren u. »verkalkbaren« (↑ Kalk, 2) Stoffen wie z. B. Metallen enthalten sein u …   Universal-Lexikon

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