Timeline of the elements

Elements counted by era

The century is that of the first retained date (confirmation, joint credit, or recognition), not that of a disputed claim. Antiquity and the Middle Ages stay outside a century.

• Before a single year : 13
• Century 17 : 1
• Century 18 : 19
• Century 19 : 49
• Century 20 : 31
• Century 21 : 4
• Synthetic (retained synthesis, no earlier use) : 25
• Others : 93

Discovery

• 1669 — White phosphorus
• 1735 — A metal distinct from bismuth
• 1751 — Kupfernickel
• 1794 — The earth from Ytterby
• 1797 — Chromium in red lead ore
• 1801 — Columbium
• 1801 — Erythronium, claim withdrawn
• 1802 — Tantalum
• 1803 — Independent work
• 1803 — Ceria in Sweden
• 1803 — Iridium
• 1803 — Osmium
• 1803 — Palladium
• 1804 — Rhodium from platinum ores
• 1811 — Violet vapors from kelp ash
• 1817 — An impurity in zinc carbonate
• 1817 — Residue from lead chambers
• about 1825 — Student work not published first
• 1826 — Publication
• 1827 — Unconfirmed announcement
• 1829 — Thoria
• 1839 — Lanthanum hidden in ceria
• 1843 — Erbium
• 1843 — Terbium in yttria
• 1844 — Ruthenium isolated
• 1860 — Blue lines
• 1861 — Red lines
• 1861 — A green line
• 1863 — Indigo line
• 1875 — Spectral line, then the metal
• 1878 — Ytterbium
• 1879 — Samarium
• 1879 — Scandium in euxenite
• 1879 — Thulium
• 1885 — The second fragment of didymium
• 1885 — Didymium split
• 1886 — Dysprosium
• 1886 — Germanium in argyrodite
• 1894 — Argon from air
• 1898 — Krypton in air residues
• 1898 — Neon in liquid air
• 1898 — Polonium in pitchblende
• 1898 — Radium
• 1898 — Xenon
• 1899 — Actinium
• 1901 — Europium
• 1902 — Emanium
• 1907 — Independent separation
• 1907 — Lutetium
• 1907 — Cassiopeium
• 1911 — Celtium
• 1923 — Hafnium in Copenhagen
• 1925 — Rhenium
• 1925 — Masurium
• 1926 — Illinium and florentium
• 1937 — Technetium
• 1939 — Actinium K
• 1945 — Promethium at Oak Ridge
• 1957 — Stockholm announcement

Isolation

• about 1250 — Isolation attributed to Albertus Magnus
• about 1772 — Fire air, not published at once
• 1774 — Metal isolated
• 1774 — First publication
• 1781 — Metal isolated
• 1783 — Metal isolated
• 1807 — Electrolytic isolation
• 1807 — Electrolytic isolation
• 1808 — Metal isolated
• 1808 — Boron prepared in London
• 1808 — Boron prepared in Paris
• 1808 — Electrolytic isolation
• 1808 — Electrolytic isolation
• 1808 — Metal isolated
• 1818 — Electrolytic isolation
• 1824 — Isolation
• 1824 — Metal isolated
• 1825 — An impure metal
• 1827 — Metal characterized
• 1828 — Isolation of the metal
• 1841 — Metal isolated
• 1867 — Metal pure enough
• 1886 — Isolation by electrolysis
• 1886 — Separation
• 1895 — Terrestrial isolation
• 1910 — Ductile metal
• 1917 — Protactinium-231
• 1917 — Parallel work

Synthesis

• 1940 — Astatine at the cyclotron
• 1940 — Neptunium
• about 1940 — Plutonium
• 1944 — Americium
• 1944 — Curium
• 1949 — Berkelium
• 1950 — Californium
• 1955 — Mendelevium
• 1961 — Lawrencium
• 1964 — Dubna claim
• 1966 — Dubna work upheld
• 1968 — Dubna claim
• 1969 — Berkeley claim
• 1970 — Berkeley claim
• 1974 — Seaborgium
• 1981 — Bohrium at Darmstadt
• 1982 — Meitnerium
• 1984 — Hassium
• 1994 — Darmstadtium
• 1994 — Roentgenium
• 1996 — Copernicium
• 1999 — Flerovium
• 2000 — Livermorium
• 2002 — The 2002 announcement
• 2003 — Moscovium
• 2003 — Dubna–Livermore claim
• 2004 — Nihonium at RIKEN
• 2006 — Oganesson
• 2010 — Tennessine

Official recognition

• 1997 — The name bohrium
• 1997 — The name dubnium
• 1997 — The name hassium
• 1997 — The name meitnerium
• 1997 — The name rutherfordium
• 1997 — The name seaborgium
• 2003 — The name darmstadtium
• 2004 — The name roentgenium
• 2010 — The name copernicium
• 2012 — The name flerovium
• 2012 — The name livermorium
• 2016 — The name moscovium
• 2016 — The name nihonium
• 2016 — The name oganesson
• 2016 — The name tennessine

Naming

• 1783 — The name hydrogen
• 1790 — The name nitrogen
• 1795 — The name titanium
• 1798 — The name tellurium
• 1844 — The name niobium

Identification

• 1746 — European identification
• 1753 — A metal distinct from lead
• 1766 — Identification of inflammable air
• 1772 — Phlogisticated air
• 1777 — Interpretation and name
• 1789 — An oxide taken for the metal
• 1789 — The earth of zircon
• 1790 — An earth distinct from baryta
• 1798 — A new earth in beryl
• 1810 — An element in its own right
• 1817 — Identification in petalite
• 1830 — Rediscovery
• 1864 — Separation from tantalum
• 1879 — Holmium named
• 1900 — Radium emanation
• 1913 — Brevium
• 1952 — Ivy Mike debris
• 1952 — Ivy Mike debris

Observation

• Antiquity — Antimony known since antiquity
• Antiquity — Carbon known since antiquity
• Antiquity — Copper known since antiquity
• Antiquity — Gold known since antiquity
• Antiquity — Iron known since antiquity
• Antiquity — Lead known since antiquity
• Antiquity — Mercury known since antiquity
• Antiquity — Silver known since antiquity
• Antiquity — Sulfur known since antiquity
• Antiquity — Tin known since antiquity
• Middle Ages — Bismuth known since the Middle Ages
• Middle Ages — Zinc known since the Middle Ages
• no single date — Platinum known before a single date
• 1735 — European description
• 1771 — Hydrofluoric acid
• 1774 — Baryta distinguished
• 1774 — A green gas
• 1778 — Molybdic acid
• 1781 — Tungstic acid
• 1782 — A new metal in a gold ore
• 1791 — Black sand from Menachan
• 1811 — An impure product
• 1868 — Solar line observed
• 1868 — Line assigned to a solar element
• 1878 — A spectral band
• 1880 — A new earth
• 1899 — Thorium emanation

Classification

• 1864 — Lothar Meyer’s table
• 1869 — Mendeleev’s periodic system
• 1913 — Moseley’s atomic number
• 1944 — Actinide series

Known before a single date

• Antiquity · Observation

  Antimony known since antiquity

  Metallic antimony and stibnite were known in antiquity. No discovery year can be assigned.

  Antimony

• Antiquity · Observation

  Carbon known since antiquity

  Charcoal and soot were worked in antiquity. No discovery year can be assigned.

  Carbon

• Antiquity · Observation

  Copper known since antiquity

  Copper was worked in antiquity. No discovery year can be assigned.

  Copper

• Antiquity · Observation

  Gold known since antiquity

  Gold was worked in antiquity. No discovery year can be assigned.

  Gold

• Antiquity · Observation

  Iron known since antiquity

  Iron was worked long before modern chemistry. No discovery year can be assigned.

  Iron

• Antiquity · Observation

  Lead known since antiquity

  Lead was worked in antiquity. No discovery year can be assigned.

  Lead

• Antiquity · Observation

  Mercury known since antiquity

  Mercury was known in antiquity. No discovery year can be assigned.

  Mercury

• Antiquity · Observation

  Silver known since antiquity

  Silver was worked in antiquity. No discovery year can be assigned.

  Silver

• Antiquity · Observation

  Sulfur known since antiquity

  Sulfur was known and used in antiquity. No discovery year can be assigned.

  Sulfur

• Antiquity · Observation

  Tin known since antiquity

  Tin was worked in antiquity. No discovery year can be assigned.

  Tin

• Middle Ages · Observation

  Bismuth known since the Middle Ages

  Bismuth was distinguished by miners and metallurgists before its eighteenth-century chemical identification. The date is not a single year.

  Bismuth

• Middle Ages · Observation

  Zinc known since the Middle Ages

  Metallic zinc was produced at Zawar, Rajasthan, long before its European identification. The date is not a single year.

  Zinc

• No single date · Observation

  Platinum known before a single date

  Platinum was worked in South America before its European description. This is not an Old World ancient discovery, and no single year is assigned.

  Platinum

Dated timeline

1. about 1250 · Isolation · claimed

   Isolation attributed to Albertus Magnus

   Tradition attributes metallic arsenic to Albertus Magnus around the mid-thirteenth century. The year is approximate and the claim has no modern laboratory notebook.

   Arsenic · Albert le Grand · Cologne

2. 1669 · Discovery · confirmed

   White phosphorus

   Brand obtains white phosphorus in Hamburg by distilling urine. This is the first element whose discovery is dated to a laboratory year.

   Phosphorus · Hennig Brand · Hamburg

3. 1735 · Discovery · confirmed

   A metal distinct from bismuth

   Brandt shows that the blue of smalt comes from a metal, cobalt, and not from bismuth.

   Cobalt · Georg Brandt · Stockholm

4. 1735 · Observation · confirmed

   European description

   Ulloa describes the platinum of the Chocó. That account does not create the pre-colonial use of the metal, which still has no single year.

   Platinum · Antonio de Ulloa · Chocó

5. 1746 · Identification · confirmed

   European identification

   Marggraf identifies zinc as a distinct metal. That does not date Indian metallurgical production, which is older and has no single year.

   Zinc · Andreas Sigismund Marggraf · Berlin

6. 1751 · Discovery · confirmed

   Kupfernickel

   Cronstedt isolates nickel from the ore miners called devil’s copper.

   Nickel · Axel Fredrik Cronstedt · Stockholm

7. 1753 · Identification · confirmed

   A metal distinct from lead

   Geoffroy shows that bismuth is not a variety of lead. Earlier metallurgical use has no single year.

   Bismuth · Claude François Geoffroy · Paris

8. 1766 · Identification · confirmed

   Identification of inflammable air

   Cavendish isolates an inflammable gas and measures its density. He does not name it hydrogen.

   Hydrogen · Henry Cavendish · London

9. 1771 · Observation · confirmed

   Hydrofluoric acid

   Scheele characterizes the acid obtained from fluorite. He does not isolate fluorine.

   Fluorine · Carl Wilhelm Scheele

10. 1772 · Identification · confirmed

    Phlogisticated air

    Rutherford isolates a residual air in which a candle does not burn. The names azote and nitrogen come later.

    Nitrogen · Daniel Rutherford

11. about 1772 · Isolation · jointly credited

    Fire air, not published at once

    Scheele prepares oxygen around 1771–1772. Publication waits until 1777: the experiment date is not the publication date.

    Oxygen · Carl Wilhelm Scheele

12. 1774 · Observation · confirmed

    Baryta distinguished

    Scheele distinguishes baryta. He does not isolate barium metal.

    Barium · Carl Wilhelm Scheele

13. 1774 · Observation · confirmed

    A green gas

    Scheele prepares chlorine and takes it for an oxygenated compound. Observing the gas is not proving that it is an element.

    Chlorine · Carl Wilhelm Scheele

14. 1774 · Isolation · confirmed

    Metal isolated

    Gahn isolates manganese. Scheele had recognized the particular nature of pyrolusite, without being the author of this isolation.

    Manganese · Johan Gottlieb Gahn · Stockholm

15. 1774 · Isolation · jointly credited

    First publication

    Priestley publishes the preparation of “dephlogisticated air.” He does not yet treat it as the principle of acids.

    Oxygen · Joseph Priestley

16. 1777 · Identification · confirmed

    Interpretation and name

    Lavoisier treats it as an element and names it oxygen. Observing the gas, publishing it, and identifying it as an element are three moments.

    Oxygen · Antoine Lavoisier · Paris

17. 1778 · Observation · confirmed

    Molybdic acid

    Scheele shows that molybdenite is not a lead or graphite ore and prepares the acid.

    Molybdenum · Carl Wilhelm Scheele

18. 1781 · Isolation · confirmed

    Metal isolated

    Hjelm reduces the acid and obtains molybdenum.

    Molybdenum · Peter Jacob Hjelm

19. 1781 · Observation · confirmed

    Tungstic acid

    Scheele prepares tungstic acid. He does not isolate the metal.

    Tungsten · Carl Wilhelm Scheele

20. 1782 · Observation · confirmed

    A new metal in a gold ore

    Müller von Reichenstein shows that a Transylvanian ore is neither antimony nor bismuth.

    Tellurium · Franz-Joseph Müller von Reichenstein

21. 1783 · Naming · confirmed

    The name hydrogen

    Lavoisier treats the gas as an element and names it for the water it forms when burned.

    Hydrogen · Antoine Lavoisier · Paris

22. 1783 · Isolation · jointly credited

    Metal isolated

    The Delhuyar brothers isolate tungsten.

    Tungsten · Juan José de Elhuyar · Fausto de Elhuyar

23. 1789 · Identification · confirmed

    An oxide taken for the metal

    Klaproth identifies a new element in pitchblende. The body he obtains is still an oxide.

    Uranium · Martin Heinrich Klaproth · Berlin

24. 1789 · Identification · confirmed

    The earth of zircon

    Klaproth identifies a new earth in zircon. He does not obtain the pure metal.

    Zirconium · Martin Heinrich Klaproth · Berlin

25. 1790 · Naming · confirmed

    The name nitrogen

    Chaptal proposes nitrogen. Lavoisier had spoken of azote. Both names refer to the same element.

    Nitrogen · Jean-Antoine Chaptal · Paris

26. 1790 · Identification · confirmed

    An earth distinct from baryta

    Crawford recognizes that strontianite is not a barium ore.

    Strontium · Adair Crawford · Strontian

27. 1791 · Observation · confirmed

    Black sand from Menachan

    Gregor recognizes a new earth in a Cornish sand. He does not isolate the pure metal.

    Titanium · William Gregor

28. 1794 · Discovery · confirmed

    The earth from Ytterby

    Gadolin describes a new earth in a mineral from Ytterby. Several elements were later separated from it.

    Yttrium · Johan Gadolin · Ytterby

29. 1795 · Naming · confirmed

    The name titanium

    Klaproth finds the earth again in rutile and names it.

    Titanium · Martin Heinrich Klaproth · Berlin

30. 1797 · Discovery · confirmed

    Chromium in red lead ore

    Vauquelin isolates chromium from crocoite.

    Chromium · Louis-Nicolas Vauquelin · Paris

31. 1798 · Identification · confirmed

    A new earth in beryl

    Vauquelin shows that beryl and emerald contain an earth distinct from alumina.

    Beryllium · Louis-Nicolas Vauquelin · Paris

32. 1798 · Naming · confirmed

    The name tellurium

    Klaproth confirms the element and names it.

    Tellurium · Martin Heinrich Klaproth · Berlin

33. 1801 · Discovery · disputed

    Columbium

    Hatchett describes columbium in an American ore. Confusion with tantalum lasts for decades.

    Niobium · Charles Hatchett · London

34. 1801 · Discovery · disputed

    Erythronium, claim withdrawn

    Del Río describes a new metal in Mexico, then withdraws and takes it for chromium. The claim is not carried through to a stable identification.

    Vanadium · Andrés Manuel del Río · Mexico City

35. 1802 · Discovery · confirmed

    Tantalum

    Ekeberg describes tantalum. Distinguishing it from niobium still required Marignac’s work.

    Tantalum · Anders Gustaf Ekeberg · Uppsala

36. 1803 · Discovery · jointly credited

    Independent work

    Klaproth identifies the same earth the same year.

    Cerium · Martin Heinrich Klaproth · Berlin

37. 1803 · Discovery · jointly credited

    Ceria in Sweden

    Berzelius and Hisinger identify a new earth in a Bastnäs ore.

    Cerium · Jöns Jacob Berzelius · Wilhelm Hisinger · Stockholm

38. 1803 · Discovery · confirmed

    Iridium

    Tennant isolates iridium from the same platinum residues as osmium.

    Iridium · Smithson Tennant · London

39. 1803 · Discovery · confirmed

    Osmium

    Tennant isolates osmium from platinum residues, together with iridium.

    Osmium · Smithson Tennant · London

40. 1803 · Discovery · confirmed

    Palladium

    Wollaston isolates palladium from platinum ores.

    Palladium · William Hyde Wollaston · London

41. 1804 · Discovery · confirmed

    Rhodium from platinum ores

    Wollaston separates rhodium after his work on palladium.

    Rhodium · William Hyde Wollaston · London

42. 1807 · Isolation · confirmed

    Electrolytic isolation

    Davy isolates potassium by electrolysis of caustic potash.

    Potassium · Humphry Davy · London

43. 1807 · Isolation · confirmed

    Electrolytic isolation

    Davy isolates sodium by electrolysis of caustic soda. The soda itself was known long before.

    Sodium · Humphry Davy · London

44. 1808 · Isolation · confirmed

    Metal isolated

    Davy isolates barium.

    Barium · Humphry Davy · London

45. 1808 · Isolation · jointly credited

    Boron prepared in London

    Davy obtains boron the same year, independently of the Paris work.

    Boron · Humphry Davy · London

46. 1808 · Isolation · jointly credited

    Boron prepared in Paris

    Gay-Lussac and Thénard prepare boron by reduction.

    Boron · Joseph Louis Gay-Lussac · Louis Jacques Thénard · Paris

47. 1808 · Isolation · confirmed

    Electrolytic isolation

    Davy isolates calcium. Lime was known as an earth, not as the free metal.

    Calcium · Humphry Davy · London

48. 1808 · Isolation · confirmed

    Electrolytic isolation

    Davy isolates magnesium. White magnesia, as a compound, had already been distinguished.

    Magnesium · Humphry Davy · London

49. 1808 · Isolation · confirmed

    Metal isolated

    Davy isolates strontium. Recognizing the earth in 1790 was not this isolation.

    Strontium · Humphry Davy · London

50. 1810 · Identification · confirmed

    An element in its own right

    Davy shows that chlorine contains no oxygen and must be counted as an element.

    Chlorine · Humphry Davy · London

51. 1811 · Discovery · confirmed

    Violet vapors from kelp ash

    Courtois obtains iodine by treating seaweed ash.

    Iodine · Bernard Courtois · Paris

52. 1811 · Observation · confirmed

    An impure product

    Gay-Lussac and Thénard obtain impure silicon. They do not establish it as the reference isolation.

    Silicon · Joseph Louis Gay-Lussac · Louis Jacques Thénard · Paris

53. 1817 · Discovery · confirmed

    An impurity in zinc carbonate

    Stromeyer identifies cadmium in a zinc carbonate. Other chemists report it the same year.

    Cadmium · Friedrich Stromeyer

54. 1817 · Identification · confirmed

    Identification in petalite

    Arfwedson recognizes a new alkali in petalite, in Berzelius’s laboratory.

    Lithium · Johan August Arfwedson · Stockholm

55. 1817 · Discovery · confirmed

    Residue from lead chambers

    Berzelius identifies selenium in the mud from roasting pyrite.

    Selenium · Jöns Jacob Berzelius · Stockholm

56. 1818 · Isolation · confirmed

    Electrolytic isolation

    Davy obtains the metal by electrolysis. The 1817 identification and this isolation remain two moments.

    Lithium · Humphry Davy · London

57. 1824 · Isolation · confirmed

    Isolation

    Berzelius prepares silicon and describes it as an element.

    Silicon · Jöns Jacob Berzelius · Stockholm

58. 1824 · Isolation · confirmed

    Metal isolated

    Berzelius isolates zirconium.

    Zirconium · Jöns Jacob Berzelius · Stockholm

59. 1825 · Isolation · disputed

    An impure metal

    Ørsted reports a metal from aluminium chloride. The purity of the sample remains disputed.

    Aluminium · Hans Christian Ørsted

60. about 1825 · Discovery · jointly credited

    Student work not published first

    Löwig obtains bromine around 1825. Balard’s publication comes first.

    Bromine · Carl Jacob Löwig

61. 1826 · Discovery · jointly credited

    Publication

    Balard publishes bromine extracted from the mother liquors of salt marshes.

    Bromine · Antoine-Jérôme Balard · Paris

62. 1827 · Isolation · confirmed

    Metal characterized

    Wöhler obtains aluminium whose metallic nature is accepted. This is not the disputed 1825 announcement.

    Aluminium · Friedrich Wöhler

63. 1827 · Discovery · rejected

    Unconfirmed announcement

    Osann believes he has found several metals in platinum residues. This announcement is not the upheld discovery of ruthenium.

    Ruthenium · Gottfried Osann

64. 1828 · Isolation · jointly credited

    Isolation of the metal

    Wöhler and Bussy obtain the metal independently. This is not the 1798 discovery of the earth.

    Beryllium · Friedrich Wöhler · Antoine Bussy

65. 1829 · Discovery · confirmed

    Thoria

    Berzelius identifies thorium in a Norwegian mineral.

    Thorium · Jöns Jacob Berzelius · Stockholm

66. 1830 · Identification · confirmed

    Rediscovery

    Sefström identifies vanadium in Swedish cast iron.

    Vanadium · Nils Gabriel Sefström

67. 1839 · Discovery · confirmed

    Lanthanum hidden in ceria

    Mosander separates lanthanum from a cerium nitrate.

    Lanthanum · Carl Gustaf Mosander · Stockholm

68. 1841 · Isolation · confirmed

    Metal isolated

    Péligot isolates uranium metal and shows that Klaproth’s product was not the metal.

    Uranium · Eugène-Melchior Péligot · Paris

69. 1843 · Discovery · confirmed

    Erbium

    Mosander separates erbium from yttria. The earth was split further afterward.

    Erbium · Carl Gustaf Mosander · Stockholm

70. 1843 · Discovery · confirmed

    Terbium in yttria

    Mosander separates terbium from the yttria of Ytterby. The names of the Ytterby earths were later reassigned.

    Terbium · Carl Gustaf Mosander · Stockholm

71. 1844 · Naming · claimed

    The name niobium

    Rose believes he has distinguished an element and names it niobium. A clean separation comes later.

    Niobium · Heinrich Rose · Berlin

72. 1844 · Discovery · confirmed

    Ruthenium isolated

    Klaus isolates ruthenium from Ural platinum residues.

    Ruthenium · Karl Karlovich Klaus

73. 1860 · Discovery · jointly credited

    Blue lines

    Bunsen and Kirchhoff discover caesium by spectroscopy in the mineral water of Dürkheim.

    Caesium · Robert Bunsen · Gustav Kirchhoff · Heidelberg

74. 1861 · Discovery · jointly credited

    Red lines

    Bunsen and Kirchhoff discover rubidium by spectroscopy in lepidolite.

    Rubidium · Robert Bunsen · Gustav Kirchhoff · Heidelberg

75. 1861 · Discovery · confirmed

    A green line

    Crookes discovers thallium by spectroscopy in lead-chamber mud.

    Thallium · William Crookes · London

76. 1863 · Discovery · jointly credited

    Indigo line

    Reich and Richter discover indium by spectroscopy in zinc blendes.

    Indium · Ferdinand Reich · Hieronymus Theodor Richter

77. 1864 · Identification · confirmed

    Separation from tantalum

    Marignac demonstrates that niobium and tantalum are two elements.

    Niobium · Jean Charles Galissard de Marignac

78. 1864 · Classification

    Lothar Meyer’s table

    Lothar Meyer orders the elements by properties and masses. This is not yet Mendeleev’s system, and it is not the discovery of an element.

    · Lothar Meyer

79. 1867 · Isolation · confirmed

    Metal pure enough

    Roscoe isolates vanadium metal. The 1830 identification was first about compounds.

    Vanadium · Henry Enfield Roscoe

80. 1868 · Observation · jointly credited

    Solar line observed

    Janssen observes an unknown yellow line in the solar chromosphere spectrum.

    Helium · Pierre Janssen

81. 1868 · Observation · jointly credited

    Line assigned to a solar element

    Lockyer assigns the same line to an element then unknown on Earth.

    Helium · Joseph Norman Lockyer

82. 1869 · Classification

    Mendeleev’s periodic system

    Mendeleev publishes a system that leaves empty spaces and predicts elements. The classification is not the discovery of gallium, scandium, or germanium.

    · Dmitri Mendeleïev · Saint Petersburg

83. 1875 · Discovery · confirmed

    Spectral line, then the metal

    Boisbaudran discovers gallium by spectroscopy and isolates it. The eka-aluminium space had been predicted, not discovered, by Mendeleev.

    Gallium · Paul-Émile Lecoq de Boisbaudran · Paris

84. 1878 · Observation · jointly credited

    A spectral band

    Soret observes a band he calls element X in erbium earths.

    Holmium · Jacques-Louis Soret

85. 1878 · Discovery · confirmed

    Ytterbium

    Marignac separates ytterbium from erbia. Lutetium was still to be distinguished from it.

    Ytterbium · Jean Charles Galissard de Marignac

86. 1879 · Identification · jointly credited

    Holmium named

    Cleve separates holmium and names it for Stockholm.

    Holmium · Per Teodor Cleve · Uppsala

87. 1879 · Discovery · confirmed

    Samarium

    Boisbaudran identifies samarium by spectroscopy in samarskite.

    Samarium · Paul-Émile Lecoq de Boisbaudran · Paris

88. 1879 · Discovery · confirmed

    Scandium in euxenite

    Nilson identifies scandium. Mendeleev had predicted a space; he did not isolate the element.

    Scandium · Lars Fredrik Nilson · Uppsala

89. 1879 · Discovery · confirmed

    Thulium

    Cleve separates thulium from erbium earths.

    Thulium · Per Teodor Cleve · Uppsala

90. 1880 · Observation · confirmed

    A new earth

    Marignac observes a new earth in samarskite.

    Gadolinium · Jean Charles Galissard de Marignac

91. 1885 · Discovery · confirmed

    The second fragment of didymium

    Von Welsbach separates neodymium from didymium. Mosander’s didymium was not a single element.

    Neodymium · Carl Auer von Welsbach

92. 1885 · Discovery · confirmed

    Didymium split

    Von Welsbach separates praseodymium from didymium, together with neodymium.

    Praseodymium · Carl Auer von Welsbach

93. 1886 · Discovery · confirmed

    Dysprosium

    Boisbaudran separates dysprosium from holmium oxide.

    Dysprosium · Paul-Émile Lecoq de Boisbaudran · Paris

94. 1886 · Isolation · confirmed

    Isolation by electrolysis

    Moissan isolates fluorine by electrolysis of potassium hydrogen fluoride.

    Fluorine · Henri Moissan · Paris

95. 1886 · Isolation · confirmed

    Separation

    Boisbaudran separates gadolinium. The 1880 observation and this separation are not the same act.

    Gadolinium · Paul-Émile Lecoq de Boisbaudran · Paris

96. 1886 · Discovery · confirmed

    Germanium in argyrodite

    Winkler isolates germanium. This is the element Mendeleev had called eka-silicon, without having it in hand.

    Germanium · Clemens Winkler

97. 1894 · Discovery · jointly credited

    Argon from air

    Rayleigh and Ramsay isolate an inert constituent of air, distinct from nitrogen.

    Argon · John William Strutt, lord Rayleigh · William Ramsay · London

98. 1895 · Isolation · confirmed

    Terrestrial isolation

    Ramsay isolates helium from uranium minerals. The 1868 solar observation was not this isolation.

    Helium · William Ramsay · London

99. 1898 · Discovery · confirmed

    Krypton in air residues

    Ramsay and Travers isolate krypton by distillation of liquid air.

    Krypton · William Ramsay · Morris Travers · London

100. 1898 · Discovery · confirmed

     Neon in liquid air

     Ramsay and Travers separate neon from liquid-air residues.

     Neon · William Ramsay · Morris Travers · London

101. 1898 · Discovery · jointly credited

     Polonium in pitchblende

     The Curies announce polonium in July 1898, before the radium of December.

     Polonium · Marie Curie · Pierre Curie · Paris

102. 1898 · Discovery · jointly credited

     Radium

     The Curies announce radium in December 1898. Isolation of weighable salts comes in the following years.

     Radium · Marie Curie · Pierre Curie · Paris

103. 1898 · Discovery · confirmed

     Xenon

     Ramsay and Travers isolate xenon in the heavy fractions of liquid air.

     Xenon · William Ramsay · Morris Travers · London

104. 1899 · Discovery · confirmed

     Actinium

     Debierne reports actinium in pitchblende residues.

     Actinium · André-Louis Debierne · Paris

105. 1899 · Observation · confirmed

     Thorium emanation

     Rutherford observes a radioactive emanation from thorium. This is not yet the identification of radium emanation as an element.

     Radon · Ernest Rutherford

106. 1900 · Identification · confirmed

     Radium emanation

     Dorn identifies radium emanation, which would be named radon.

     Radon · Friedrich Ernst Dorn

107. 1901 · Discovery · confirmed

     Europium

     Demarçay isolates europium from earths that had been taken for samarium.

     Europium · Eugène-Anatole Demarçay · Paris

108. 1902 · Discovery · claimed

     Emanium

     Giesel independently finds a substance he calls emanium. It is later identified with actinium.

     Actinium · Friedrich Oskar Giesel

109. 1907 · Discovery · jointly credited

     Independent separation

     James also achieves the separation. Publication priority favors Urbain, without erasing the parallel work.

     Lutetium · Charles James

110. 1907 · Discovery · jointly credited

     Lutetium

     Urbain separates lutetium from ytterbium and proposes this name.

     Lutetium · Georges Urbain · Paris

111. 1907 · Discovery · jointly credited

     Cassiopeium

     Von Welsbach separates the same element and calls it cassiopeium. The name kept is lutetium.

     Lutetium · Carl Auer von Welsbach

112. 1910 · Isolation · confirmed

     Ductile metal

     Hunter prepares titanium metal pure enough to be ductile. The 1791 observation was not this isolation.

     Titanium · Matthew A. Hunter

113. 1911 · Discovery · rejected

     Celtium

     Urbain announces celtium as element 72. This identification is not upheld.

     Hafnium · Georges Urbain · Paris

114. 1913 · Identification · confirmed

     Brevium

     Fajans and Göhring identify the short-lived isotope 234Pa. They do not isolate the long-lived isotope 231Pa.

     Protactinium · Kazimierz Fajans · Oswald Helmuth Göhring

115. 1913 · Classification

     Moseley’s atomic number

     Moseley links X-ray spectra to atomic number. The order of the table no longer rests on mass alone.

     · Henry Moseley · Manchester

116. 1917 · Isolation · jointly credited

     Protactinium-231

     Hahn and Meitner isolate protactinium-231.

     Protactinium · Otto Hahn · Lise Meitner · Berlin

117. 1917 · Isolation · jointly credited

     Parallel work

     Soddy and Cranston obtain the same isotope independently.

     Protactinium · Frederick Soddy · John Arnold Cranston

118. 1923 · Discovery · confirmed

     Hafnium in Copenhagen

     Coster and Hevesy identify hafnium by X-ray spectroscopy in zircons.

     Hafnium · Dirk Coster · George de Hevesy · Copenhagen

119. 1925 · Discovery · confirmed

     Rhenium

     Noddack, Tacke, and Berg identify rhenium. Their parallel masurium claim, for element 43, is not upheld.

     Rhenium · Walter Noddack · Ida Noddack · Otto Berg · Berlin

120. 1925 · Discovery · rejected

     Masurium

     Noddack, Tacke, and Berg announce masurium. This claim to element 43 is not upheld.

     Technetium · Walter Noddack · Ida Noddack · Otto Berg · Berlin

121. 1926 · Discovery · rejected

     Illinium and florentium

     Several announcements of the 1920s, under the names illinium and florentium, are not upheld as the discovery of element 61.

     Promethium

122. 1937 · Discovery · confirmed

     Technetium

     Perrier and Segrè identify element 43 in molybdenum irradiated in the Berkeley cyclotron and analyzed in Palermo.

     Technetium · Carlo Perrier · Emilio Segrè · Palermo

123. 1939 · Discovery · confirmed

     Actinium K

     Perey identifies francium as a decay product of actinium, at the Radium Institute.

     Francium · Marguerite Perey · Paris

124. 1940 · Synthesis · confirmed

     Astatine at the cyclotron

     Corson, MacKenzie, and Segrè produce astatine by bombarding bismuth.

     Astatine · Dale R. Corson · Kenneth Ross MacKenzie · Emilio Segrè · Berkeley

125. 1940 · Synthesis · confirmed

     Neptunium

     McMillan and Abelson identify neptunium after irradiating uranium.

     Neptunium · Edwin McMillan · Philip Abelson · Berkeley

126. about 1940 · Synthesis · confirmed

     Plutonium

     The Berkeley team produces plutonium in 1940–1941. Publication is delayed by wartime secrecy.

     Plutonium · Glenn T. Seaborg · Edwin McMillan · Joseph W. Kennedy · Arthur C. Wahl · Berkeley

127. 1944 · Synthesis · confirmed

     Americium

     Seaborg, James, Morgan, and Ghiorso produce americium by successive irradiations of plutonium.

     Americium · Glenn T. Seaborg · Ralph A. James · Leon O. Morgan · Albert Ghiorso · Chicago

128. 1944 · Synthesis · confirmed

     Curium

     The same team produces curium by bombarding plutonium with alpha particles.

     Curium · Glenn T. Seaborg · Ralph A. James · Albert Ghiorso · Berkeley

129. 1944 · Classification

     Actinide series

     Seaborg proposes placing the heavy elements from actinium onward as a series analogous to the lanthanides. That is a classification choice, not the synthesis of a new element.

     · Glenn T. Seaborg · Chicago

130. 1945 · Discovery · confirmed

     Promethium at Oak Ridge

     Marinsky, Glendenin, and Coryell identify element 61 in fission products. The public announcement follows in 1947.

     Promethium · Jacob A. Marinsky · Lawrence E. Glendenin · Charles D. Coryell · Oak Ridge

131. 1949 · Synthesis · confirmed

     Berkelium

     Thompson, Ghiorso, and Seaborg produce berkelium at Berkeley.

     Berkelium · Stanley G. Thompson · Albert Ghiorso · Glenn T. Seaborg · Berkeley

132. 1950 · Synthesis · confirmed

     Californium

     Thompson, Street, Ghiorso, and Seaborg produce californium at Berkeley.

     Californium · Stanley G. Thompson · Kenneth Street Jr. · Albert Ghiorso · Glenn T. Seaborg · Berkeley

133. 1952 · Identification · confirmed

     Ivy Mike debris

     Einsteinium is identified in debris from the Ivy Mike thermonuclear test, analyzed at Berkeley. This is not a cyclotron synthesis.

     Einsteinium · Albert Ghiorso · Enewetak

134. 1952 · Identification · confirmed

     Ivy Mike debris

     Fermium is identified in the same debris as einsteinium. The team is wider than the single name kept here for the index.

     Fermium · Albert Ghiorso · Enewetak

135. 1955 · Synthesis · confirmed

     Mendelevium

     Ghiorso and colleagues produce mendelevium atom by atom by bombarding einsteinium.

     Mendelevium · Albert Ghiorso · Glenn T. Seaborg · Berkeley

136. 1957 · Discovery · rejected

     Stockholm announcement

     The Nobel Institute announces element 102. This claim is not upheld. The name nobelium was nevertheless kept.

     Nobelium · Stockholm

137. 1961 · Synthesis · confirmed

     Lawrencium

     Ghiorso and his team produce lawrencium at Berkeley by bombarding californium.

     Lawrencium · Albert Ghiorso · Berkeley

138. 1964 · Synthesis · jointly credited

     Dubna claim

     Dubna announces element 104. Berkeley disputes the evidence. IUPAC later reaches a shared credit, without turning 1964 into an exclusive certainty.

     Rutherfordium · Gueorgui Flerov · Dubna

139. 1966 · Synthesis · confirmed

     Dubna work upheld

     Discovery priority for nobelium is assigned to the Dubna work, not to the 1957 announcement.

     Nobelium · Gueorgui Flerov · Dubna

140. 1968 · Synthesis · jointly credited

     Dubna claim

     Dubna claims element 105. The evidence is disputed with Berkeley.

     Dubnium · Gueorgui Flerov · Dubna

141. 1969 · Synthesis · jointly credited

     Berkeley claim

     Berkeley announces an independent synthesis. The name rutherfordium is adopted in 1997 inside this dispute.

     Rutherfordium · Albert Ghiorso · Berkeley

142. 1970 · Synthesis · jointly credited

     Berkeley claim

     Berkeley announces its own synthesis. Official credit will be shared.

     Dubnium · Albert Ghiorso · Berkeley

143. 1974 · Synthesis · confirmed

     Seaborgium

     The Berkeley and Livermore team produces element 106. A parallel Dubna claim does not carry priority.

     Seaborgium · Albert Ghiorso · Glenn T. Seaborg · Berkeley

144. 1981 · Synthesis · confirmed

     Bohrium at Darmstadt

     The GSI team produces element 107.

     Bohrium · Peter Armbruster · Gottfried Münzenberg · Darmstadt

145. 1982 · Synthesis · confirmed

     Meitnerium

     GSI produces element 109. The detailed publication follows the first observation.

     Meitnerium · Peter Armbruster · Gottfried Münzenberg · Darmstadt

146. 1984 · Synthesis · confirmed

     Hassium

     GSI produces element 108.

     Hassium · Peter Armbruster · Gottfried Münzenberg · Darmstadt

147. 1994 · Synthesis · confirmed

     Darmstadtium

     Hofmann and the GSI team produce element 110.

     Darmstadtium · Sigurd Hofmann · Darmstadt

148. 1994 · Synthesis · confirmed

     Roentgenium

     GSI produces element 111 in the same year as element 110.

     Roentgenium · Sigurd Hofmann · Darmstadt

149. 1996 · Synthesis · confirmed

     Copernicium

     GSI produces element 112.

     Copernicium · Sigurd Hofmann · Darmstadt

150. 1997 · Official recognition · officially recognized

     The name bohrium

     IUPAC adopts the name bohrium in 1997.

     Bohrium

151. 1997 · Official recognition · officially recognized

     The name dubnium

     IUPAC adopts the name dubnium in 1997.

     Dubnium

152. 1997 · Official recognition · officially recognized

     The name hassium

     IUPAC adopts the name hassium in 1997.

     Hassium

153. 1997 · Official recognition · officially recognized

     The name meitnerium

     IUPAC adopts the name meitnerium in 1997.

     Meitnerium

154. 1997 · Official recognition · officially recognized

     The name rutherfordium

     IUPAC adopts the name rutherfordium and a shared credit between Dubna and Berkeley.

     Rutherfordium

155. 1997 · Official recognition · officially recognized

     The name seaborgium

     The name seaborgium, for a time disputed because Seaborg was alive, is adopted in 1997.

     Seaborgium

156. 1999 · Synthesis · confirmed

     Flerovium

     The Dubna institute, with Livermore, produces element 114 by calcium-48 reactions.

     Flerovium · Iouri Oganessian · Dubna

157. 2000 · Synthesis · confirmed

     Livermorium

     Dubna and Livermore produce element 116.

     Livermorium · Iouri Oganessian · Dubna

158. 2002 · Synthesis · disputed

     The 2002 announcement

     A first announcement of element 118 in 2002 is not the synthesis later upheld. It remains disputed.

     Oganesson · Iouri Oganessian · Dubna

159. 2003 · Official recognition · officially recognized

     The name darmstadtium

     IUPAC adopts the name darmstadtium in 2003.

     Darmstadtium

160. 2003 · Synthesis · confirmed

     Moscovium

     Dubna, with American collaborators, produces element 115.

     Moscovium · Iouri Oganessian · Dubna

161. 2003 · Synthesis · claimed

     Dubna–Livermore claim

     A decay chain seen in the calcium-48 experiments is offered as evidence for element 113. The priority later upheld is not this one.

     Nihonium · Iouri Oganessian · Dubna

162. 2004 · Synthesis · confirmed

     Nihonium at RIKEN

     Morita’s team produces element 113 at Wako. This is the synthesis whose priority is upheld.

     Nihonium · Kosuke Morita · Wako

163. 2004 · Official recognition · officially recognized

     The name roentgenium

     IUPAC adopts the name roentgenium in 2004.

     Roentgenium

164. 2006 · Synthesis · confirmed

     Oganesson

     Dubna and Livermore produce oganesson by bombarding californium with calcium-48.

     Oganesson · Iouri Oganessian · Dubna

165. 2010 · Official recognition · officially recognized

     The name copernicium

     IUPAC adopts the name copernicium in 2010.

     Copernicium

166. 2010 · Synthesis · confirmed

     Tennessine

     A collaboration led at Dubna, with a berkelium target prepared at Oak Ridge, produces element 117.

     Tennessine · Iouri Oganessian · Dubna

167. 2012 · Official recognition · officially recognized

     The name flerovium

     IUPAC adopts the name flerovium in 2012.

     Flerovium

168. 2012 · Official recognition · officially recognized

     The name livermorium

     IUPAC adopts the name livermorium in 2012.

     Livermorium

169. 2016 · Official recognition · officially recognized

     The name moscovium

     IUPAC adopts the name moscovium in 2016.

     Moscovium

170. 2016 · Official recognition · officially recognized

     The name nihonium

     IUPAC adopts the name nihonium in 2016, after crediting RIKEN.

     Nihonium

171. 2016 · Official recognition · officially recognized

     The name oganesson

     IUPAC adopts the name oganesson in 2016.

     Oganesson

172. 2016 · Official recognition · officially recognized

     The name tennessine

     IUPAC adopts the name tennessine in 2016. The usual French form is tennesse.

     Tennessine