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Chemical Elements, indium to mendelevium,
Chart 4 of 8

indium | iodine | iridium | iron | krypton | lanthanum | lawrencium | lead | lithium | lutetium | magnesium | manganese | meitnerium | mendelevium

This is fourth of eight groups of chem elements available in this cross-reference searches.

The Chemical Elements Chart is here.

The Chemical-Elements Table Index is here.

Symbol: In
Atomic number: 49
Year discovered: 1863
Discovered by: Ferdinand Reich (1799-1882), a German mineralogist, and Hieronymus Theodor Richter (1824-1898), a German mineralogist.

Additional information:
  • Reich suspected that a yellow precipitate he had obtained from a zinc ore might contain a new metal, but because he was color-blind, he had his assistant, Theodor Richter, examine it spectroscopically.
  • It was found and spectroscopically identified as a minor component in zincores.
  • Until 1924, a gram or so constituted the world’s supply of this element in isolated form.
  • In fact, it is probably about as abundant as silver.
  • Indium is a very soft, silvery-white metal with a brilliant luster.
  • The pure metal gives a high-pitched “scream” when bent.
  • It is useful for making low-melting alloys.
  • An alloy of 24% indium and 76% gallium is liquid at room temperature.
  • Canada produces the majority of the world’s supply of indium.
  • Indium would not normally be made in the laboratory as it is commercially available.
  • It is a by-product of the formation of lead and zinc.
  • Indium metal is isolated by the electrolysis of indium salts in water.
  • Further processes are required to make very pure indium for electronics purposes.
  • Among other uses, indium has the unique property of being able to “wet” glass and other surfaces, which makes it valuable for producing hermetic seals between glass, metals, quartz, ceramics, marble, etc.
Name in other languages:
French: indium
German: Indium
Italian: indio
Spanish: indio

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Symbol: I
Atomic number: 53
Year discovered: 1811
Discovered by: Bernard Courtois (1777-1838), a French chemist.

Additional information:
  • Courtois was in the business of manufacturing potassium nitrate (needed in the making of gunpowder).
  • He got it from potassium carbonate (potash), which in turn he got from seaweed.
  • He isolated iodine from treating seaweed ash with sulphuric acid while recovering sodium and potassium compounds.
  • One day, in 1811, he added too much acid and, on heating, he obtained a beautiful violet vapor.
  • After condensing the vapor, he found dark, lustrous crystals.
  • Iodine is a bluish-black, lustrous solid.
  • Courtois suspected it might be a new element and he passed it on to other chemists for confirmation.
  • It was a new element, and Humphry Davy suggested that it be named “iodine”, from the Greek word for “violet”.
  • It volatilizes at ambient temperatures into a pretty blue-violet gas with an irritating odor.
  • It forms compounds with most elements, but is less reactive than the other halogens, which displace it from iodides.
  • Iodine exhibits some metallic-like properties. It dissolves readily in chloroform, carbon tetrachloride, or carbon disulphide to form beautiful purple solutions.
  • It is only slightly soluble in water.
  • Iodine compounds are important in organic chemistry and very useful in medicine and photography.
  • In humans, not having enough iodine often results in goiter.
  • The deep blue color with starch solution is characteristic of the free element of iodine.
  • It is assimilated by seaweeds from which it may be recovered, and is found in Chilean saltpetre, caliche, old salt brines, and salt wells.
  • Iodine is available commercially so it is not normally necessary to make it in the laboratory.
  • Iodine occurs in seawater but in much smaller quantities than chloride or bromide.
  • With suitable sources of brine, it is recovered commercially through the treatment of brine with chlorine gas and flushing through with air.
  • In this treatment, iodide is oxidized to iodine by the chlorine gas.
Name in other languages:
French: iode
German: Iod
Italian: iodio
Spanish: yodo

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Symbol: Ir
Atomic number: 77
Year discovered: 1803
Discovered by: Smithson Tennant (1761-1815), a British chemist, Antoine-François de Comte Fourcroy (1755-1809), a French chemist, Louis Vanquelin, and Hippolyte Collet-Descotils.

Additional information:
  • Osmium was discovered in 1803 by Smithson Tennant in the dark colored residue left when crude platinum is dissolved by aqua regia (a mixture of hydrochloric and nitric acid). This dark residue contains both osmium and iridium
  • The name iridium is appropriate, for its salts are highly colored.
  • Iridium is white, similar to platinum, but with a slight yellowish cast.
  • It is very hard and brittle, making it very difficult to machine, form, or work.
  • It is the most corrosion resistant metal known, and was used in making the standard meter bar of Paris, which is a 90% platinum and 10% iridium alloy. This meter bar has since been replaced as a fundamental unit of length.
  • Iridium is not damaged by any of the acids nor by aqua regia which dissolves gold and platinum; but it is affected by molten salts.
  • Because of difficulties in preparation and fabrication, the pure metal does not have important applications by itself.
  • The element’s principal use is in the preparation of platinum alloys.
  • Pure platinum is a soft metal and unsatisfactory for many uses.
  • Alloyed with from 5% to 10% iridium, platinum forms a readily worked metal, much harder and stiffer and more resistant to chemical attack.
Name in other languages:
French: iridium
German: Iridium
Italian: iridio
Spanish: iridio

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Symbol: Fe
Atomic number: 26
Year discovered: Prehistoric
Discovered by: Unknown.

Additional information:
  • The Assyrians and Egyptians made considerable use of iron.
  • Iron was known in prehistoric times. Genesis 4: 22, says that Tubal-Cain, seven generations from Adam, was an instructor of workers in iron and copper; and iron was utilized to make tools and weapons in the time of David.
  • Smelted iron artifacts have been identified from around 3000 B.C.
  • A remarkable iron pillar, dating to about A.D. 400, remains standing today in Delhi, India.
  • This solid pillar is wrought iron and about 7.5 meters high by 40 centimeters in diameter.
  • Corrosion to the pillar has been minimal despite its exposure to the weather since its construction.
  • Iron is a relatively abundant element in the universe.
  • It is found in the sun and many types of stars in considerable quantity.
  • Iron nuclei are very stable.
  • Iron is a vital constituent of plant and animal life, and is the key component of hemoglobin (blood).
  • The pure metal is not often encountered in commerce, but it is usually alloyed with carbon or other metals.
  • The pure metal is very reactive chemically, and rapidly corrodes, especially in moist air or at elevated temperatures. Any car owner knows this.
  • Iron metal is a silvery, lustrous metal that has important magnetic properties.
  • Iron ranks second in abundance among the metals and fourth in abundance among the elements.
  • The earth’s core is largely metallic iron, but in the crust the element has had an opportunity to react with other substances and the free metal is rarely found except in meteorites or disseminated as minute specula in basaltic rocks.
Name in other languages:
French: fer
German: Eisen
Italian: ferro
Spanish: hierro

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Symbol: Kr
Atomic number: 36
Year discovered: 1898
Discovered by: William Ramsay (1852-1916), British chemist, and Morris William Travers (1872-1961), British chemist.

Additional information:
  • Krypton was discovered in 1898 by Sir William Ramsay and his student Morris Travers in the residue left after liquid air had nearly boiled away.
  • Krypton was left in the residue after boiling away water, oxygen, nitrogen, helium, and argon from the sample of air.
  • Neon was discovered by a similar procedure by the same workers just a few weeks later.
  • Krypton is characterized by its brilliant green and orange spectral lines.
  • The spectral lines of krypton are easily produced and some are very sharp.
  • Under normal conditions krypton is a colorless, odorless, and fairly expensive gas.
  • Krypton is available commercially in cylinders at high pressure.
  • It finds some application in gaseous tube lighting and in negative glow lamps for Christmas-tree ornaments, etc.
  • Krypton also is used in a type of lamp that produces a flash of light of extremely short duration; such bulbs are employed in high-speed photography.
  • If krypton and xenon were used in place of argon to fill hot-filament incandescent lamps, the efficiency and life of the lamps would be increased but so would their cost.
Name in other languages:
French: krypton
German: Krypton
Italian: cripto
Spanish: kriptón

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Symbol: La
Atomic number: 57
Year discovered: 1839
Discovered by: Carl Gustaf Mosander (1797-1858), a Swedish chemist.

Additional information:
  • Carl Mosander recognized the element lanthanum in impure cerium nitrate in 1839.
  • While studying a compound of cerium, he found a new element which he named “lanthanum” from a Greek word meaning “hidden”, because it had been hidden so effectively in those minerals.
  • His extraction resulted in oxide lanthana.
  • A number of other lanthanides (rare-earths) were later discovered by the identification of the impurities in yttrium and cerium compounds.
  • Lanthanum is silvery white, malleable, ductile, and soft enough to be cut with a knife.
  • It is one of the most reactive of the rare-earth metals.
  • It oxidizes rapidly when exposed to air.
  • Cold water attacks lanthanum slowly, and hot water attacks it much more rapidly.
  • The metal reacts directly with elemental carbon, nitrogen, boron, selenium, silicon, phosphorus, sulphur, and with halogens.
  • Lanthanum metal is available commercially so it is not normally necessary to make it in the laboratory, which is just as well as it is difficult to separate it from pure metal.
  • This is largely because of the way it is found in nature.
  • The lanthanoids are found in nature in a number of minerals.
  • The most important are xenotime, monazite, and bastnaesite.
  • The most common lanthanoids in these minerals are, cerium, lanthanum, neodymium, and praseodymium.
  • Monazite also contains thorium and ytrrium which makes handling difficult since thorium and its decomposition products are radioactive.
  • For many purposes it is not particularly necessary to separate the metals, but if separation into individual metals is required, the process is complex.
  • Initially, the metals are extracted as salts from the ores by extraction with sulphuric acid, hydrochloric acid, and sodium hydroxide.
  • It is a component of misch metal, which is used as cigarette-lighter flints, as a deoxidizer in electron tubes, and in metallurgy.
  • The oxide is a component of special glasses used in photographic lenses.
Name in other languages:
French: lanthane
German: Lanthan
Italian: lantanio
Spanish: lantano

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Symbol: Lr
Atomic number: 103
Year discovered: 1961
Discovered by: Albert Ghiorso (born July 15, 1915), Torbjorn Sikkeland, Almon Larsh, and Robert M. Latimer; discovered at the Radiation Laboratory, University of California at Berkeley.

Additional information:
  • The discoverers proposed that the new element be named “lawrencium” in honor of Ernest Orlando Lawrence (1901-1958), physicist and inventor of the cyclotron, a device for accelerating nuclear particles to high speeds.
  • Dr. Lawrence was director (1936 onward) of the Radiation Laboratory, where this and so many other transuranium elements were discovered.
  • He was an authority on nuclear, biological, and medical physics.
  • Lawrencium is a synthetic “rare earth metal” which does not occur in the environment.
  • Lawrencium is a synthetic chemical element which is not found in nature.
Name in other languages:
French: lawrencium
German: Lawrencium
Italian: lawrentio
Spanish: lawrencio

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Symbol: Pb
Atomic number: 82
Year discovered: Prehistoric
Discovered by: Unknown.

Additional information:
  • Lead has been known for ages and is mentioned in Exodus (The Old Testament Bible).
  • Coins or medallions of lead are found in ancient Egyptian ruins and it seems probable that the extraction of lead from its ores by smelting was the first such practice recognized by man.
  • During Roman civilization, the use of lead was widespread for both utilitarian and ornamental purposes.
  • Many examples of lead water pipe, still in serviceable condition, have been discovered in Roman ruins; and ornamental casting of lead 2000 years old are not uncommon in several parts of the world.
  • Lead pipes, bearing the insignia of Roman emperors and used as drains from the baths, are still in service.
  • Alchemists believed lead to be the oldest metal and associated it with the planet Saturn.
  • They spent a lot of time trying to “transmute” lead into gold.
  • Lead is a bluish-white lustrous metal.
  • It is very soft, highly malleable, ductile, and a relatively poor conductor of electricity.
  • It is very resistant to corrosion but tarnishes upon exposure to air.
  • Alloys include pewter and solder.
  • Tetraethyl lead is still used in some grades of gasoline but it is being phased out because of environmental-pollution problems.
  • Lead is considered the fifth most important metal, exceeded only by iron, copper, aluminum, and zinc.
  • The metallurgy of this metal is so interrelated with other elements that both its production rate and market price are influenced to a large degree by the supply and demand of several related elements, among which are zinc, silver, copper, gold, bismuth, and antimony.
Name in other languages:
French: plomb
German: Blei
Italian: piombo
Spanish: plomo

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Symbol: Li
Atomic number: 3
Year discovered: 1817
Discovered by: Johan August Arfvedson (1792-1841), a Swedish chemist from Stockholm.

Additional information:
  • The mineral petalite was discovered by the Brazilian scientist José Bonifácio de Andrada e Silva towards the end of the 18th century while visiting Sweden.
  • Lithium was discovered by Johan August Arfvedson in 1817 during an analysis of petalite ore, an ore now recognized to be taken from the Swedish island of Utö.
  • Arfvedson subsequently discovered lithium in other minerals (spodumene and lepidolite) containing lithium.
  • C. G. Gmelin observed, in 1818, that lithium salts result in flames that are a bright red color.
  • Neither Gmelin nor Arfvedson were able to isolate the element itself from lithium salts, for example by heating the oxide with iron or carbon.
  • The first isolation of elemental lithium was achieved later by W. T. Brande and Sir Humphrey Davy by the electrolysis of lithium oxide.
  • In 1855, Robert Bunsen and A. Mattiessen isolated larger quantities of the metal by electrolysis of lithium chloride.
  • In 1923, the first commercial production of lithium metal was achieved by Metallgesellschaft AG in Germany using the electrolysis of a molten mixture of lithium chloride and potassium chloride.
  • A freshly cut lithium chunk is silvery, but it tarnishes in a minute or so in air resulting in a grey surface.
  • It is used in combination with aluminium and magnesium for light-weight alloys, and is also used in batteries, some greases, some glasses, and in medicine.
  • It has been used as a degasifier in the production of high-conductivity copper and bronze castings and is also used in the synthesis of Vitamin A.
  • Lithium compounds are used in lubricants and ceramics, which consume the largest quantities, and in air conditioning, welding, and brazing.
Name in other languages:
French: lithium
German: Lithium
Italian: litio
Spanish: litio

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Symbol: Lu
Atomic number: 71
Year discovered: 1907-1908
Discovered by: Georges Urbain (1872-1938), a French chemist, and by Carl Auer, Freiherr von Welsbach (1858-1929), an Austrian chemist, working independently.

Additional information:
  • In 1907, Georges Urbain described a process by which Marignac’s ytterbium (1879) could be separated into the two elements, ytterbium (neoytterbium) and lutetium.
  • These elements were identical with “aldebaranium” and “cassiopeium”, independently discovered by von Welsbach at about the same time.
  • Pure metal lutetium has been isolated only in recent years and is one of the more difficult to prepare.
  • It can be produced by the reduction of anhydrous by an alkali or alkaline earth metal.
  • The metal is silvery white and relatively stable in air.
  • It is a rare earth metal and perhaps the most expensive of all rare elements.
Name in other languages:
French: lutécium
German: Lutetium
Italian: lutezio
Spanish: lutecio

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Symbol: Mg
Atomic number: 12
Year discovered: 1755 and 1808
Discovered by: Joseph Black (1728-1799), a Scottish chemist, in 1755; and Sir Humphry Davy (1778-1829), an English chemist.

Additional information:
  • In 1618, a farmer at Epsom, England, attempted to get his cows to drink water drawn from a well.
  • This they refused to drink because of the water’s bitter taste.
  • However the farmer noticed that the water seemed to heal scratches and rashes.
  • The fame of Epsom salts spread as a result.
  • Eventually these salts were recognized to be magnesium sulphate.
  • Joseph Black recognized magnesium as an element, in 1755, when he showed that the two substances, oxide and magnesia, were entirely different and not lime as was generally thought.
  • It was isolated by Sir Humphry Davy in 1808 who electrolyzed a mixture of magnesia and mercuric oxide.
  • Davy’s first suggestion for a name was magnium but the name magnesium is now used.
  • Magnesium is the eighth most abundant element in the earth’s crust although not found in it’s elemental form.
  • Magnesium is a grayish-white, fairly tough metal.
  • It tarnishes slightly in air, and finely divided magnesium readily ignites upon heating in air and burns with a dazzling white flame.
  • Normally magnesium is coated with a layer of oxide, that protects magnesium from air and water.
  • Magnesium is an important element for plant and animal life.
  • Michael Faraday, in 1833, was the first to succeed in producing metallic magnesium by electrolysis of molten magnesium chloride, using a voltaic cell.
  • Robert Bunsen achieved the same result, in 1852, his electrolytic cell corresponding in construction to the principle of the modern cell.
  • Magnesium was formerly associated in the minds of many people almost exclusively with pyrotechnics (fire works), and for many years the chief production was used for this purpose, as well as for flash ribbon and flash powder in photography and, in wartime, for incendiary bombs.
  • The increasing emphasis upon weight reduction, both in industrial applications and in consumer goods, gave magnesium an importance far beyond those earlier uses.
Name in other languages:
French: magnésium
German: Magnesium
Italian: magnesio
Spanish: magnesio

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Symbol: Mn
Atomic number: 25
Year discovered: 1774
Discovered by: Johann Gottlieb Gahn (1745-1818), Swedish mineralogist and chemist.

Additional information:
  • Manganese was first recognized as an element by the Swedish chemist, C. W. Scheele, while working with pyrolusite, manganese dioxide ore, and it was isolated by his associate Johann Gottlieb Gahn in the same year.
  • He reduced the dioxide, as the mineral pyrolusite, with charcoal (essentially carbon) by heating and the result was a sample of the metal manganese.
  • Scheele was also involved in the discovery of a number of elements, though he never managed to get undisputed credit for a single one of them.
  • By 1774, he had done most of the preliminary work that led to the discovery of the element managanese.
  • His friend, the Swedish mineralogist Johan Gottlieb Gahn; however, completed the final step and got credit for the discovery.
  • The metal is gray-white, resembling iron, but is harder and very brittle.
  • It is chemically reactive, and decomposes slowly in cold water.
  • Manganese is widely distributed throughout the animal kingdom.
  • It is an important trace element and may be essential for utilization of vitamin B.
  • It is vital to plant and animal life and is essential to reproduction in animals.
  • Manganese is present in quantity on the floor of oceans and it is an important component of steel.
  • The addition of manganese in the Bessemer steel-making process, initiated in 1856 by Robert Mushet, made that process a practical success.
  • In 1882, Robert Hadfield discovered the high-manganese steels which bear his name.
  • The use of manganese is essential in steel manufacture for deoxidation and the control of sulfur content, and this application is said to account for over 90% of the manganese consumed in all forms in the United States.
  • Somewhat less than 13 pounds of manganese, chiefly in the form of ferromanganese, is used for each ton of steel produced, and no substitute exists for it.
Name in other languages:
French: manganése
German: Mangan
Italian: manganese
Spanish: manganeso

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Symbol: Mt
Atomic number: 109
Year discovered: 1982
Discovered by: Peter Armbruster, Gottfried Münzenber, and their co-workers at Gesellschaft für Schwerionenforschung (GSI) in Darmstadt, Germany.

Additional information:
  • Lise Meitner (1878-1968) was a distinguished Austrian physicist, whose main personal achievement (among many others) was the explanation of the relation between beta and gamma rays.
  • She was born in Vienna on November 7, 1878, the third of eight children of a Viennese lawyer.
  • After receiving her doctorate, in 1906, she went to Berlin, in 1907, and joined the chemist Otto Hahn in research on radioactivity; she also studied under Max Planck and for a time was his assistant.
  • During their three decades of joint work, she and Hahn discovered protactinium and several other radioactive substances.
  • Lise Meitner, with her nephew Otto R. Frisch, after clarifying the physical characteristics of the division of a heavy atomic nucleus, proposed, early in 1939, the name “fission” for the process.
  • In August, 1982, the first atom of the element meitnerium with atomic number 109 was detected at the Gesellschaft für Schwerionenforschung (GSI) in Darmstadt, Germany.
  • The isotope of element 109, that was discovered, has an atomic mass number of 266 (that is, 266 times heavier than hydrogen).
  • The new element was produced by fusing an iron and a bismuth atom together in a reaction that produces a neutron.
  • This was achieved by accelerating the iron atoms to high energy in the heavy ion accelerator UNILAC at GSI.
  • Element meitnerium was formerly known as unnilennium (Une) which is the Latin equivalent for the number “109”.
Name in other languages:
French: meitnerium
German: Meitnerium
Italian: meitnerio
Spanish: meitnerio

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Symbol: Md
Atomic number: 101
Year discovered: 1955
Discovered by: Albert Ghiorso (born July 15, 1915), Glenn Theodore Seaborg (1912-1999), American physicist, Bernard Harvey, Gregory Choppin, and Stanley G. Thompson.

Additional information:
  • Mendeléyev, the ninth transuranium element of the actinide series to be discovered, was first identified by Seaborg and others in 1955 as a product of the bombardment of the einsteinium isotope with helium ions.
  • Dmitri Ivanovich Mendeléyev (1834-1907) was a Russian chemist who arranged the chemical elements in the periodic table according to their atomic weights and predicted the existence of the elements gallium, scandium, and germanium before their discovery.
  • He was born at Tobolsk, Siberia, on February 7 (new style; January 27, old style), 1834.
  • In 1890, he resigned from his position as a professor and in 1893, he became the director of the bureau of weights and measures, a post which he occupied until his death at St. Pertersburg on February 2 (new style) or January 20 (old style), 1907.
  • Mendeléyev's name, like that of Lothar Meyer, is best known for his work on the periodic law.
  • Various chemists had traced numerical sequences among the atomic weights of some of the elements and noted connections between them and the properties of the different substances.
  • Mendéleyev is given credit for developing a “full expression to the generalization, and to treat it not merely as a system of classifying the elements according to certain observed facts, but as a ‘law of nature’ which could be relied upon to predict new facts.” Encyclopedia Britannica
  • In 1871, he was led by certain gaps in his tables to assert the existence of three new elements so far unknown to the chemist and to assign them and their compounds definite properties.
  • These three he called eka-boron, eka-aluminum, and eka-silicon.
  • His prophecy was completely vindicated within 15 years by the discovery and study of gallium in 1875, scandium in 1879, and germanium in 1886.
  • In several cases, he questioned the correctness of the “accepted atomic weights,” because he did not believe they complied with the periodic law, and here also, he was justified by subsequent investigation.
Name in other languages:
French: mendélévium
German: Mendelevium
Italian: mendelevio
Spanish: mendelevio

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