Carl Wilhelm Scheele

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Carl Wilhelm Scheele
Carl Wilhelm Scheele from Familj-Journalen1874.png
Carl Scheele
Born(1742-12-09)9 December 1742
Died21 May 1786(1786-05-21) (aged 43)
Köping, Sweden
Nationality German-Swedish
Known forDiscovered oxygen (independently), molybdenum, manganese, barium, chlorine, tungsten and more
Scientific career
Fields Chemistry

Carl Wilhelm Scheele (German: [ˈʃeːlə] , Swedish:  [ˈɧêːlɛ] ; 9 December 1742 – 21 May 1786 [1] ) was a Swedish German [2] pharmaceutical chemist.


Scheele discovered oxygen (although Joseph Priestley published his findings first), and identified molybdenum, tungsten, barium, hydrogen, and chlorine, among others. Scheele discovered organic acids tartaric, oxalic, uric, lactic, and citric, as well as hydrofluoric, hydrocyanic, and arsenic acids. [3] He preferred speaking German to Swedish his whole life, as German was commonly spoken among Swedish pharmacists. [4]


Scheele was born in Stralsund, [1] in western Pomerania, which at the time was a Swedish Dominion inside the Holy Roman Empire. Scheele's father, Joachim (or Johann [1] ) Christian Scheele, was a grain dealer and brewer [1] from a respected Pomeranian family.[ citation needed ] His mother was Margaretha Eleanore Warnekros. [1]

Friends of Scheele's parents taught him the art of reading prescriptions and the meaning of chemical and pharmaceutical signs. [1] Then, in 1757, at the age of fourteen, Carl was sent to Gothenburg as an apprentice pharmacist [4] to another family friend and apothecary, Martin Andreas Bauch. Scheele retained this position for eight years. During this time he ran experiments late into the night and read the works of Nicolas Lemery, Caspar Neumann, Johann von Löwenstern-Kunckel and Georg Ernst Stahl (the champion of the phlogiston theory). Much of Scheele's later theoretical speculations were based upon Stahl. [1]

In 1765 Scheele worked under the progressive and well-informed apothecary C. M. Kjellström in Malmö, and became acquainted with Anders Jahan Retzius who was a lecturer at the University of Lund and later a professor of chemistry at Stockholm. Scheele arrived in Stockholm between 1767 and 1769 and worked as a pharmacist. [1] During this period he discovered tartaric acid and with his friend, Retzius, studied the relation of quicklime to calcium carbonate. [1] While in the capital, he also became acquainted with figures including Abraham Bäck, Peter Jonas Bergius, Bengt Bergius and Carl Friedreich von Schultzenheim. [1]

In the fall of 1770 Scheele became director of the laboratory of the great pharmacy of Locke, at Uppsala, which is about 40 miles north of Stockholm. The laboratory supplied chemicals to Professor of Chemistry Torbern Bergman. A friendship developed between Scheele and Bergman after Scheele analyzed a reaction which Bergman and his assistant, Johan Gottlieb Gahn, could not resolve. The reaction was between melted saltpetre and acetic acid that produced a red vapor. [1] [5] Further study of this reaction later led to Scheele's discovery of oxygen (see "The theory of phlogiston" below). Based upon this friendship and respect, Scheele was given free use of Bergman's laboratory. Both men were profiting from their working relationship. In 1774 Scheele was nominated by Peter Jonas Bergius to be a member of the Royal Swedish Academy of Sciences and was elected 4 February 1775. [1] In 1775 Scheele also managed for a short time a pharmacy in Köping. Between the end of 1776 and the beginning of 1777 Scheele established his own business there. [1]

On 29 October 1777, Scheele took his seat for the first and only time at a meeting of the Academy of Sciences and on 11 November passed the examination as apothecary before the Royal Medical College, doing so with the highest honours. After his return to Köping he devoted himself, outside of his business, to scientific researches which resulted in a long series of important papers. [1]

Isaac Asimov called him "hard-luck Scheele" because he made a number of chemical discoveries that were later credited to others.[ citation needed ]

Existing theories before Scheele

By the time he was a teenager, Scheele had learned the dominant theory of gases which in the 1770s was the phlogiston theory. Phlogiston, classified as "matter of fire", was supposed to be released from any burning material, and when it was exhausted, combustion would stop. When Scheele discovered oxygen he called it "fire air" as it supported combustion. Scheele explained oxygen using phlogistical terms because he did not believe that his discovery disproved the phlogiston theory.

Before Scheele made his discovery of oxygen, he studied air. Air was thought to be an element that made up the environment in which chemical reactions took place but did not interfere with the reactions. Scheele's investigation of air enabled him to conclude that air was a mixture of "fire air" and "foul air;" in other words, a mixture of two gases. Scheele performed numerous experiments in which he heated substances such as saltpetre (potassium nitrate), manganese dioxide, heavy metal nitrates, silver carbonate and mercuric oxide. In all of these experiments, he isolated the same gas: his "fire air," which he believed combined with phlogiston in materials to be released during heat-releasing reactions.

However, his first publication, Chemische Abhandlung von der Luft und dem Feuer, was delivered to the printer Swederus in 1775, but not published until 1777, at which time both Joseph Priestley and Antoine Lavoisier had already published their experimental data and conclusions concerning oxygen and the phlogiston theory. Carl was credited for finding oxygen with two other people, Joseph Priestley and Antoine Lavoisier. The first English edition, Chemical Observation and Experiments on Air and Fire was published in 1780, with an introduction "Chemical Treatise on Air and Fire". [6]

The theory of phlogiston

Engraving on the title page of Scheele's Chemical Treatise on Air and Fire (1777)
(d. Konigl. Schwed. Acad. d. Wissenschaft Mitgliedes, Chemische Abhandlung von der Luft und dem Feuer) ScheeleRoyalSwdAcadChemObservatnsAir&Fire.jpg
Engraving on the title page of Scheele's Chemical Treatise on Air and Fire (1777)
(d. Königl. Schwed. Acad. d. Wissenschaft Mitgliedes, Chemische Abhandlung von der Luft und dem Feuer)

Scheele achieved astonishingly prolific and important results without the expensive laboratory equipment to which his Parisian contemporary Antoine Lavoisier was accustomed. Through the studies of Lavoisier, Priestley, Scheele, and others, chemistry was made a standardized field with consistent procedures. Although Scheele was unable to grasp the significance of his discovery of the substance that Lavoisier later named oxygen, his work was essential for the abandonment of the long-held theory of phlogiston. [7]

Scheele's study of the gas not yet named oxygen was prompted by a complaint by Torbern Olof Bergman, a professor at Uppsala University who would eventually become Scheele's friend. Bergman informed Scheele that the saltpeter he had purchased from Scheele's employer, after long heating, produced red vapors (now known to be nitrogen dioxide) when it came into contact with acetic acid. Scheele's quick explanation was that the saltpeter had absorbed phlogiston with the heat (had been reduced to nitrite, in modern terms) and gave off a new phlogisticated gas as an active principle when combined with an acid (even a weak acid).

Bergman next suggested that Scheele analyze the properties of manganese (IV) oxide. It was through his studies of manganese (IV) oxide that Scheele developed his concept of "fire air" (his name for oxygen). He ultimately obtained oxygen by heating mercuric oxide, silver carbonate, magnesium nitrate, and other nitrate salts. Scheele wrote about his findings to Lavoisier who was able to see the significance of the results. His discovery of oxygen (ca. 1771) was chronologically earlier than the corresponding work of Priestley and Lavoisier, but he did not publish this discovery until 1777, after both of his rivals had published. [8]

Although Scheele would always believe in some form of the phlogiston theory, his work reduced phlogiston to an unusually simple form, complicated only by the fact that chemists of Scheele's day still believed that light and heat were elements and were to be found in combination with them. Thus, Scheele assumed that hydrogen was composed of phlogiston (a reducing principle lost when objects were burned) plus heat. Scheele speculated that his fire air or oxygen (which he found the active part of air, estimating it to compose one quarter of air) combined with the phlogiston in objects to produce either light or heat (light and heat were presumed to be composed of differing proportions of phlogiston and oxygen).

When other chemists later showed water is produced when burning hydrogen and that rusting of metals added weight to them and that passing water over hot iron gave hydrogen, Scheele modified his theory to suggest that oxygen was the salt (or "saline principle" of water), and that when added to iron, water was reproduced, which added weight to the iron as rust.

Pyrolusite or MnO2. Pyrolusite radiating.jpg
Pyrolusite or MnO2.

New elements and compounds

In addition to his joint recognition for the discovery of oxygen, Scheele is argued to have been the first to discover other chemical elements such as barium (1772), [9] manganese (1774), [10] molybdenum (1778), [11] and tungsten (1781), [12] as well as several chemical compounds, including citric acid, [13] lactic acid, [14] glycerol, [15] hydrogen cyanide (also known, in aqueous solution, as prussic acid), [16] hydrogen fluoride, [17] and hydrogen sulfide (1777). [18] In addition, he discovered a process similar to pasteurization, [19] along with a means of mass-producing phosphorus (1769), leading Sweden to become one of the world's leading producers of matches.

Chlorine gas. Chlorine-sample.jpg
Chlorine gas.

Scheele made one other very important scientific discovery in 1774, arguably more revolutionary than his isolation of oxygen. He identified lime, silica, and iron in a specimen of pyrolusite (impure manganese dioxide) given to him by his friend, Johann Gottlieb Gahn, but could not identify an additional component (this was the manganese, which Scheele recognized was present as a new element, but could not isolate). When he treated the pyrolusite with hydrochloric acid over a warm sand bath, a yellow-green gas with a strong odor was produced. [20] He found that the gas sank to the bottom of an open bottle and was denser than ordinary air. He also noted that the gas was not soluble in water. It turned corks a yellow color and removed all color from wet, blue litmus paper and some flowers. He called this gas with bleaching abilities, "dephlogisticated muriatic acid" (dephlogisticated hydrochloric acid, or oxidized hydrochloric acid). Eventually, Sir Humphry Davy named the gas chlorine, with reference to its pale green colour.

Chlorine's bleaching properties were eventually turned into an industry by Berzelius, and became the foundation of a second industry of disinfection and deodorization of putrefied tissue and wounds (including wounds in living humans) in the hands of Labarraque, by 1824.


Statue of Scheele in Koping, Sweden. Carl Wilhelm Scheele in Koping.JPG
Statue of Scheele in Köping, Sweden.

In the fall of 1785, Scheele began to suffer from symptoms described as kidney disease. [1] In early 1786, he also contracted a disease of the skin, which, combined with kidney problems, so enfeebled him that he could foresee an early death. With this in mind, he married the widow of his predecessor, [1] Pohl, two days before he died, so that he could pass undisputed title to his pharmacy and his possessions to her.

While Scheele's experiments generated substances which have long since been found to be hazardous, the compounds and elements he used to start his experiments were dangerous to begin with, especially heavy metals. Like most of his contemporaries, in an age where there were few methods of chemical characterisation, Scheele would smell and taste any new substances he discovered. [21] Cumulative exposure to arsenic, mercury, lead, their compounds and perhaps hydrofluoric acid which he had discovered, as well as other substances took their toll on Scheele, who died at the early age of 43, on 21 May 1786, at his home in Köping. Doctors said that he died of mercury poisoning.

Published papers

Memoires de chymie, 1785, French translation by Mme. Claudine Picardet Memoires de chymie Scheele RGNb10364341.02.vol 1785.tif
Mémoires de chymie, 1785, French translation by Mme. Claudine Picardet
Early history of chlorine, 1944 Scheele, Carl Wilhelm - Early history of chlorine, 1944 - BEIC 7863226.jpg
Early history of chlorine, 1944

All of the following papers were published by Scheele within a span of fifteen years. [1]

  1. (1771) Fluospar and its Acid
  2. (1774) "Braunstein" or Magnesia [ Manganese ], two papers
  3. (1775) Benzoin Salt [ Benzoic Acid ]
  4. Arsenic and its Acid
  5. Silica, Alumina, and Alum
  6. Urinary Calculi
  7. (1777) Chemical Treatise on Air and Fire
  8. (1778) Wet Process for Preparing Mercurius dulcis [ Calomel ]
  9. Simple Process for Preparing Pulvis Algarothi [ oxychloride of antimony ]
  10. Molybdenum
  11. (1778) Preparation of a New Green Color [22]
  12. (1779) On the Quantity of Pure Air daily present in the Atmosphere
  13. Decomposition of Neutral Salts by Lime or Iron
  14. Plumbago
  15. Heavy spar
  16. (1780) Fluospar
  17. Milk and its Acid [14]
  18. Acid of Milk sugar
  19. On the Relationship of Bodies
  20. (1781) Tungsten
  21. The Combustible Substance in Crude Lime
  22. Preparation of White Lead
  23. (1782) Ether
  24. Preservation of Vinegar
  25. Coloring Matter in Berlin Blue [16]
  26. (1783) Berlin Blue
  27. Peculiar Sweet Principle from Oils and Fats [ Glycerin ] [15]
  28. (1784) Attempt to Crystallize Lemon juice
  29. Constituents of Rhubarb-earth [ Calcium Oxalate ] and Preparation of Acetosella Acid [ Oxalic Acid ]
  30. The Coloring "Middle-salt" of "Blood lye" [Yellow Prussiate of Potassium]
  31. Air-acid [ Carbonic Acid ]; Benzoic Acid. Lapis infernalis [1] ("Air-acid" is Carbon dioxide)
  32. Sweet Principle from Oils and Fats. Air-acid
  33. (1785) Acid of Fruits, especially of Raspberry
  34. Phosphate of Iron; and Pearl-salt
  35. Occurrence of Rhubarb-earth [see 29] in various Plants
  36. Preparation of Magnesia alba
  37. Fulminating Gold. Corn oil [ Fusel oil ]. Calomel
  38. Air-acid
  39. Lead amalgam
  40. Vinegar-naphtha
  41. Lime. Ammonia or Volatile Alkali
  42. Malic Acid and Citric Acid
  43. Air, Fire, and Water
  44. (1786) The Essential Salt of Galls [ Gallic Acid ]
  45. Nitric Acid
  46. Oxide of Lead. Fuming Sulphuric Acid
  47. Pyrophorus
  48. Peculiarities of Hydrofluoric Acid.

Scheele's papers appeared first in the Transactions of the Swedish Academy of Sciences, and in various periodicals such as Lorenz Florenz Friedrich von Crell's Chemische Annalen . Scheele's work was collected and published in four languages beginning with Mémoires de Chymie by Mme. Claudine Picardet in 1785 and Chemical Essays by Thomas Beddoes in 1786, followed by Latin and German. [23] Another English translation was published by Dr Leonard Dobbin, in 1931. [24]

See also


  1. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 Castle, Fred'k A.; Rice, Chas, eds. (1886). "Carl Wilhelm Scheele". American Druggist. New York, U.S.A. 15 (August): 157–158. Retrieved 8 March 2021.
  2. "Karl Wilhelm Scheele |".
  3. Richard Myers, The Basics of Chemistry (2003)
  4. 1 2 Fors, Hjalmar 2008. Stepping through Science’s Door: C. W. Scheele, from Pharmacist's Apprentice to Man of Science. Ambix 55: 29–49
  5. Scheele found that when potassium nitrite (KNO2) was reacted with acetic acid, nitrogen dioxide was produced. See: Lennartson, Anders (2020). Carl Wilhelm Scheele and Torbern Bergman: The Science, Lives and Friendship of Two Pioneers in Chemistry. Cham, Switzerland: Springer Nature Switzerland AG. pp. 101–104. ISBN   9783030491949.
  6. p101, A Source Book in Chemistry, 1400–1900, Henry Marshall Leicester, Herbert S. Klickstein – 1969
  7. J. R. Partington (1962). A History of Chemistry, vol. 3. Macmillan. pp. 205–36.
  8. J. R. Partington (1962). A History of Chemistry, vol. 3. Macmillan. pp. 219–20.
  9. Scheele's laboratory notebooks show that during 1771-1772, he observed a "besondere Erde" (peculiar earth [i.e., metal oxide]) in pyrolusite (an ore that contains mainly manganese dioxide, MnO2). See: Scheele, Carl Wilhelm (1892). Nordenskiöld, A.E. (ed.). Carl Wilhelm Scheele: Nachgelassene Briefe und Aufzeichnungen [Carl Wilhelm Scheele: Posthumously published letters and notes] (in German and Latin). Stockholm, Sweden: P.A. Norstedt & Söner. p. 457. From p. 457: "In Gewächsen muss die besondere Erde, welche aus magn. nigra et acidis … mit acido vitrioli ein solches Præcipitat." (In plants, [there] must be present the peculiar earth [i.e., metal oxide], which arises from magnesia nigra [i.e., pyrolusite] and acid via precipitation with oil of vitriol [i.e., concentrated sulfuric acid], for plant ash which is well rinsed so that all potassium sulfate disappears, gives — [when it's] dissolved with nitric acid and salt acid [i.e., hydrochloric acid] — such a precipitate [when it's treated] with sulfuric acid.) See also pages 455, 456, and 461.
    • In 1774, Scheele further investigated barium in pyrolusite: Scheele (1774). "Om brunsten, eller magnesia, och dess egenskaper" [On brown-stone [i.e., pyrolusite] or magnesia, and its properties]. Kongliga Vetenskaps Academiens Handlingar (Proceedings of the Royal Scientific Academy [of Sweden]) (in Swedish). 35: 89–116. From page 102: "4:to Något af en ny Jord-art, hvilken, så mycket jag vet, ännu är obekant." (4th Something of a new type of ore [i.e., mineral], which, as far as I know, is still unknown.) From page 112: "Den besynnerliga Jord-arten, som visar sig vid alla klara uplösningar af Brunstenen, hvarom något är anfördt i 18. §." (This peculiar type of ore [i.e., mineral] appears in all clear solutions of brown-stone, concerning which something is stated in section 18.)
  10. Scheele (1774). "Om brunsten, eller magnesia, och dess egenskaper" [On brown-stone [i.e., pyrolusite] or magnesia, and its properties]. Kongliga Vetenskaps Academiens Handlingar (Proceedings of the Royal Scientific Academy [of Sweden]) (in Swedish). 35: 89–116.
  11. Scheele, Carl Wilhelm (1778). "Försök med Blyerts, Molybdæna" [Experiment with lead, molybdæna]. Kongliga Vetenskaps Academiens Handlingar (in Swedish). 39: 247–255.
  12. Scheele, Carl Wilhelm (1781). "Tungstens bestånds-delar" [Tungsten's constituent components]. Kongliga Vetenskaps Academiens Nya Handlingar (New Proceedings of the Royal Academy of Sciences [of Sweden]) (in Swedish). 2: 89–95.
  13. Scheele, Carl Wilhelm (1784). "Anmärkning om Citron-Saft, samt sätt att crystallisera den samma" [Note on lemon juice, as well as ways to crystallize the same]. Kongliga Vetenskaps Academiens Nya Handlingar (New Proceedings of the Royal Academy of Science) (in Swedish). 5: 105–109.
  14. 1 2 Scheele, Carl Wilhelm (1780). "Om Mjölk och dess syra" [About milk and its acid]. Kongliga Vetenskaps Academiens Nya Handlingar (New Proceedings of the Royal Academy of Science) (in Swedish). 1: 116–124.
  15. 1 2 Scheele, Carl Wilhelm (1783). "Rön beträffande ett särskilt Socker-Ämne uti exprimerade Oljor och Fettmor" [Findings concerning a particular sweet substance in expressed oils and fatty substances]. Kongliga Vetenskaps Academiens Nya Handlingar (New Proceedings of the Royal Academy of Science) (in Swedish). 4: 324–329.
  16. 1 2 See:
    • Scheele, Carl W. (1782). "Försök, beträffande det färgande ämnet uti Berlinerblå" [Experiment concerning the coloring substance in Berlin blue]. Kongliga Vetenskaps Academiens Nya Handlingar (New Proceedings of the Royal Academy of Science [of Sweden] (in Swedish). 3: 264–275.
    • Reprinted in Latin as: Scheele, Carl Wilhelm; Schäfer, Gottfried Heinrich, trans. (1789). "De materia tingente caerulei berolinensis". In Hebenstreit, Ernst Benjamin Gottlieb (ed.). Opuscula Chemica et Physica[Chemical and Physical Works] (in Latin). Vol. 2. Leipzig (Lipsiae), (Germany): Johann Godfried Müller. pp. 148–174.
  17. Scheele (1771) "Undersŏkning om fluss-spat och dess syra" (Investigation of fluorite and its acid), Kongliga Vetenskaps Academiens Handlingar (Proceedings of the Royal Academy of Science [of Sweden]), 32 : 129–138.
  18. Scheele, Carl Wilhelm (1777). Chemische Abhandlung von der Luft und dem Feuer [Chemical treatise on air and fire] (in German). Upsala, Sweden: Magnus Swederus. pp. 149–155. See: § 97. Die stinckende Schwefel Luft (The stinking sulfur air [i.e., gas]).
  19. Scheele, Carl Wilhelm (1782). "Anmärkningar om sättet att conserva ättika" [Notes on the way to preserve vinegar]. Kongliga Vetenskaps Academiens Nya Handlingar (New Proceedings of the Royal Academy of Science) (in Swedish). 3: 120–122.
  20. See:
    • Scheele (1774). "Om brunsten, eller magnesia, och dess egenskaper" [On pyrolusite or magnesia, and its properties]. Kongliga Vetenskaps Academiens Handlingar (Proceedings of the Royal Scientific Academy [of Sweden] (in Swedish). 35: 89–116. On pages 93–94 (paragraph 6), "Med den vanliga Salt-syran." ([Reactions of manganese dioxide] with the standard salt-acid [i.e., hydrochloric acid]), Scheele describes a gas (chlorine) that was produced when he reacted manganese dioxide with hydrochloric acid. Further experiments with chlorine appear in paragraphs 23–26, pages 105–110.
    • An English translation of the relevant passages about chlorine from Scheele's article appears in: Leicester, Henry M. (1952). A Source Book in Chemistry, 1400–1900. New York, New York, USA: McGraw-Hill. pp. 109–110. ISBN   9780674822306.
  21. Asimov, Isaac (1966). The Noble Gases. ISBN   978-0465051298
  22. Scheele, Carl Wilhelm (1778). "Tilrednings-saettet af en ny groen Faerg" [Method of preparation of a new green color]. Kungliga Vetenskaps Akademiens Handlingar (in Swedish). 39: 327–328.
  23. Ferguson, John. "Karl Wilhelm Scheele". Encyclopaedia Britannica. 1902. Retrieved 8 December 2017.
  24. Journal of the Chemical Society: obituaries (L Dobbin), 1952

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The chemical revolution, also called the first chemical revolution, was the early modern reformulation of chemistry that culminated in the law of conservation of mass and the oxygen theory of combustion. During the 19th and 20th century, this transformation was credited to the work of the French chemist Antoine Lavoisier. However, recent work on the history of early modern chemistry considers the chemical revolution to consist of gradual changes in chemical theory and practice that emerged over a period of two centuries. The so-called scientific revolution took place during the sixteenth and seventeenth centuries whereas the chemical revolution took place during the seventeenth and eighteenth centuries.

Pneumatic chemistry Very first studies of the role of gases in the air in combustion reactions

In the history of science, pneumatic chemistry is an area of scientific research of the seventeenth, eighteenth, and early nineteenth centuries. Important goals of this work were the understanding of the physical properties of gases and how they relate to chemical reactions and, ultimately, the composition of matter. The rise of phlogiston theory, and its replacement by a new theory after the discovery of oxygen as a gaseous component of the Earth atmosphere and a chemical reagent participating in the combustion reactions, were addressed in the era of pneumatic chemistry.

<i>Experiments and Observations on Different Kinds of Air</i>

Experiments and Observations on Different Kinds of Air (1774–86) is a six-volume work published by 18th-century British polymath Joseph Priestley which reports a series of his experiments on "airs" or gases, most notably his discovery of oxygen gas.

Claudine Picardet French chemist, mineralogist, meteorologist and translator

Claudine Picardet was a chemist, mineralogist, meteorologist and scientific translator. Among the French chemists of the late eighteenth century she stands out for her extensive translations of scientific literature from Swedish, English, German and Italian to French. She translated three books and thousands of pages of scientific papers, which were published as well as circulated in manuscript form. She hosted renowned scientific and literary salons in Dijon and Paris, and was an active participant in the collection of meteorological data. She helped to establish Dijon and Paris as scientific centers, substantially contributing to the spread of scientific knowledge during a critical period in the chemical revolution.

Most nonmetallic elements were discovered after the freezing of mercury in 1759, by the German-Russian physicist Braun and the Russian polymath Lomonosov. Before then, carbon, sulfur and antimony were known in antiquity; and arsenic and phosphorus were discovered in, respectively, the middle ages, and the Renaissance. In the ensuring century and a half, from 1766 to 1895, all the remaining nonmetallic elements, bar radon, astatine, and oganesson had been isolated. The latter three were discovered in 1898, 1940 and 2002.