Per Teodor Cleve (10 February 1840 – 18 June 1905) was a Swedish

chemist A chemist (from Greek ''chēm(ía)'' alchemy; replacing ''chymist'' from Medieval Latin ''alchemist'') is a scientist trained in the study of chemistry. Chemists study the composition of matter and its properties. Chemists carefully describe th ...

biologist A biologist is a scientist who conducts research in biology. Biologists are interested in studying life on Earth, whether it is an individual Cell (biology), cell, a multicellular organism, or a Community (ecology), community of Biological inter ...

mineralogist Mineralogy is a subject of geology specializing in the scientific study of the chemistry, crystal structure, and physical (including optical) properties of minerals and mineralized artifacts. Specific studies within mineralogy include the proce ...

and

oceanographer Oceanography (), also known as oceanology and ocean science, is the scientific study of the oceans. It is an Earth science, which covers a wide range of topics, including ecosystem dynamics; ocean currents, waves, and geophysical fluid dynamic ...

. He is best known for his discovery of the chemical elements

holmium Holmium is a chemical element with the symbol Ho and atomic number 67. It is a rare-earth element and the eleventh member of the lanthanide series. It is a relatively soft, silvery, fairly corrosion-resistant and malleable metal. Like a lot of othe ...

and

thulium Thulium is a chemical element with the symbol Tm and atomic number 69. It is the thirteenth and third-last element in the lanthanide series. Like the other lanthanides, the most common oxidation state is +3, seen in its oxide, halides and other c ...

. Born in Stockholm in 1840, Cleve earned his

BSc A Bachelor of Science (BS, BSc, SB, or ScB; from the Latin ') is a bachelor's degree awarded for programs that generally last three to five years. The first university to admit a student to the degree of Bachelor of Science was the University ...

and PhD from

Uppsala University Uppsala University ( sv, Uppsala universitet) is a public university, public research university in Uppsala, Sweden. Founded in 1477, it is the List of universities in Sweden, oldest university in Sweden and the Nordic countries still in opera ...

in 1863 and 1868, respectively. After receiving his PhD, he became an assistant professor of chemistry at the university. He later became professor of general and agricultural chemistry. In 1874 he theorised that

didymium Didymium ( el, , twin) is a mixture of the elements praseodymium and neodymium. It is used in safety glasses for glassblowing and blacksmithing, especially with a gas ( propane)-powered forge, where it provides a filter that selectively block ...

was in fact two elements; this theory was confirmed in 1885 when

Carl Auer von Welsbach Carl Auer von Welsbach (1 September 1858 – 4 August 1929), who received the Austrian noble title of Freiherr Auer von Welsbach in 1901, was an Austrian scientist and inventor, who separated didymium into the elements neodymium and praseo ...

discovered

neodymium Neodymium is a chemical element with the symbol Nd and atomic number 60. It is the fourth member of the lanthanide series and is considered to be one of the rare-earth metals. It is a hard, slightly malleable, silvery metal that quickly tarnishes i ...

and

praseodymium Praseodymium is a chemical element with the Symbol (chemistry), symbol Pr and the atomic number 59. It is the third member of the lanthanide series and is considered to be one of the rare-earth metals. It is a soft, silvery, malleable and ductile ...

. In 1879 Cleve discovered holmium and thulium. His other contributions to chemistry include the discovery of

aminonaphthalenesulfonic acids Aminonaphthalenesulfonic acids are compounds with the composition C10H6(NH2)(SO3H), being derived from naphthalene (C10H8) substituted by an amino and sulfonic acid groups. These compounds are colorless solids. They are useful precursors to dyes ...

, also known as Cleve's acids. From 1890 on he focused on biological studies. He developed a method of determining the age and order of late glacial and postglacial

deposits A deposit account is a bank account maintained by a financial institution in which a customer can deposit and withdraw money. Deposit accounts can be savings accounts, Transaction account#Current accounts, current accounts or any of several othe ...

from the types of

diatom A diatom (Neo-Latin ''diatoma''), "a cutting through, a severance", from el, διάτομος, diátomos, "cut in half, divided equally" from el, διατέμνω, diatémno, "to cut in twain". is any member of a large group comprising sev ...

fossils in the deposits, and wrote a seminal text in the field of oceanography. He died in 1905 at age 65.

Early life

Cleve was born in

Stockholm Stockholm () is the Capital city, capital and List of urban areas in Sweden by population, largest city of Sweden as well as the List of urban areas in the Nordic countries, largest urban area in Scandinavia. Approximately 980,000 people liv ...

, Sweden, as the thirteenth child of his father, a merchant known as Fredrik Theodor Cleve. Cleve's ancestors on his father's side came from western Germany and settled in Sweden in the late 18th century. Cleve showed interest in

natural science Natural science is one of the branches of science concerned with the description, understanding and prediction of natural phenomena, based on empirical evidence from observation and experimentation. Mechanisms such as peer review and repeatab ...

and natural history from an early age. He attended the Stockholms Lyceum in 1858, studying chemistry and biology. He gained a

Bachelor of Science A Bachelor of Science (BS, BSc, SB, or ScB; from the Latin ') is a bachelor's degree awarded for programs that generally last three to five years. The first university to admit a student to the degree of Bachelor of Science was the University of ...

degree from the University of Uppsala in 1863 and a PhD from the same university in 1868.

Career

In 1860, aged 20, Cleve became

assistant professor Assistant Professor is an academic rank just below the rank of an associate professor used in universities or colleges, mainly in the United States and Canada. Overview This position is generally taken after earning a doctoral degree and general ...

mineralogy Mineralogy is a subject of geology specializing in the scientific study of the chemistry, crystal structure, and physical (including optical) properties of minerals and mineralized artifacts. Specific studies within mineralogy include the proces ...

at the

University of Uppsala Uppsala University ( sv, Uppsala universitet) is a public research university in Uppsala, Sweden. Founded in 1477, it is the oldest university in Sweden and the Nordic countries still in operation. The university rose to significance during ...

, and was appointed assistant professor of chemistry in 1868. He also taught at the Royal Institute of Technology between 1870 and 1874, and eventually became professor of

general A general officer is an Officer (armed forces), officer of highest military ranks, high rank in the army, armies, and in some nations' air forces, space forces, and marines or naval infantry. In some usages the term "general officer" refers t ...

and

agricultural chemistry Agricultural chemistry is the study of chemistry, especially organic chemistry and biochemistry, as they relate to agriculture—agricultural production, the processing of raw products into foods and beverages, and environmental monitoring and r ...

at the University of Uppsala. He was the chair of chemistry at the University of Uppsala starting in 1874. He was also the president of the

Nobel Committee for Chemistry The Nobel Committee for Chemistry is the Nobel Committee responsible for proposing laureates for the Nobel Prize in Chemistry. Cleve's first work was ''Några ammoniakaliska chromföreningar'' (''Some compounds of ammonia and chromium'', 1861). He also wrote several more papers on complex compounds, including the compounds of platinum. Additionally, Cleve synthesized several hundred complex platinum compounds. Cleve visited a number of laboratories in England, France, Italy, and Switzerland in the 1860s. While in Paris, he visited the laboratory of Charles-Adolphe Wurtz and also made a number of friends there. Per Teodor Cleve c1900

Cleve worked on the synthesis of complex chemical compounds until 1872. He theorized in 1874 that the element

consisted of two elements. This theory was proven right with the discovery of

and

in 1885 by

. In 1879, Cleve proved that the newly discovered element

scandium Scandium is a chemical element with the symbol Sc and atomic number 21. It is a silvery-white metallic d-block element. Historically, it has been classified as a rare-earth element, together with yttrium and the Lanthanides. It was discovered in ...

was an element predicted by

Dmitri Mendeleev Dmitri Ivanovich Mendeleev (sometimes transliterated as Mendeleyev or Mendeleef) ( ; russian: links=no, Дмитрий Иванович Менделеев, tr. , ; 8 February Old_Style_and_New_Style_dates">O.S._27_January.html" ;"title="O ...

to be "eka-boron". He isolated a quantity of scandium in this same year and determined its

atomic weight Relative atomic mass (symbol: ''A''; sometimes abbreviated RAM or r.a.m.), also known by the deprecated synonym atomic weight, is a dimensionless physical quantity defined as the ratio of the average mass of atoms of a chemical element in a giv ...

. He discovered the element

in 1879 by examining a sample of erbium oxide. While removing impurities from a sample of erbium oxide, Cleve discovered a brown substance and a green substance, and the brown substance was

holmium oxide Holmium(III) oxide, or holmium oxide is a chemical compound of a rare-earth element holmium and oxygen with the formula Ho2O3. Together with dysprosium(III) oxide (Dy2O3), holmium oxide is one of the most powerfully paramagnetic substances known. ...

(the green substance was

thulium oxide Thulium(III) oxide is a pale green solid compound, with the formula Tm2 O3. It was first isolated in 1879, from an impure sample of erbia, by Swedish chemist A chemist (from Greek ''chēm(ía)'' alchemy; replacing ''chymist'' from Medieval ...

). However, this sample may have been impure. He separated

from an erbium oxide sample in 1879. Additionally, Cleve and

Abraham Langlet Nils Abraham Langlet (9 July 1868 – 30 March 1936; known by his second given name) was a Swedish chemist. Biography Langlet was born in Södertälje, Sweden. He was the son of architect Emil Victor Langlet (1824–1898) and his wife, author Cla ...

discovered

helium Helium (from el, ἥλιος, helios, lit=sun) is a chemical element with the symbol He and atomic number 2. It is a colorless, odorless, tasteless, non-toxic, inert, monatomic gas and the first in the noble gas group in the periodic table. ...

in the mineral cleveite in 1895. Cleve discovered six forms of dichloronaphthalene and discovered

, which are sometimes named after him. He prepared a number of nitrosulfonic acids as well. In 1883, Cleve was the first person to describe the plankton species '' Nitzschia seriata''. In 1890, Cleve began to mainly focus on the field of

biology Biology is the scientific study of life. It is a natural science with a broad scope but has several unifying themes that tie it together as a single, coherent field. For instance, all organisms are made up of cells that process hereditary i ...

, mainly studying freshwater

algae Algae (; singular alga ) is an informal term for a large and diverse group of photosynthetic eukaryotic organisms. It is a polyphyletic grouping that includes species from multiple distinct clades. Included organisms range from unicellular mic ...

s, and

plankton Plankton are the diverse collection of organisms found in Hydrosphere, water (or atmosphere, air) that are unable to propel themselves against a Ocean current, current (or wind). The individual organisms constituting plankton are called plankt ...

. Cleve participated in a Swedish expedition to

Spitsbergen Spitsbergen (; formerly known as West Spitsbergen; Norwegian: ''Vest Spitsbergen'' or ''Vestspitsbergen'' , also sometimes spelled Spitzbergen) is the largest and the only permanently populated island of the Svalbard archipelago in northern Norw ...

in 1898. While on this mission, he discovered a number of species of spumellarians, nassellarians, and

phaeodarian Phaeodarea, or Phaeodaria, is a group of amoeboid cercozoan organisms. They are traditionally considered radiolarians, but in molecular trees do not appear to be close relatives of the other groups, and are instead placed among the Cercozoa. They ...

s. Cleve, in collaboration with Otto Höglund prepared numerous previously-undiscovered

salts In chemistry, a salt is a chemical compound consisting of an ionic assembly of positively charged cations and negatively charged anions, which results in a compound with no net electric charge. A common example is table salt, with positively cha ...

yttrium Yttrium is a chemical element with the symbol Y and atomic number 39. It is a silvery-metallic transition metal chemically similar to the lanthanides and has often been classified as a "rare-earth element". Yttrium is almost always found in com ...

and erbium. The two also did work on the chemistry of the chemical elements

thorium Thorium is a weakly radioactive metallic chemical element with the symbol Th and atomic number 90. Thorium is silvery and tarnishes black when it is exposed to air, forming thorium dioxide; it is moderately soft and malleable and has a high me ...

and

lanthanum Lanthanum is a chemical element with the symbol La and atomic number 57. It is a soft, ductile, silvery-white metal that tarnishes slowly when exposed to air. It is the eponym of the lanthanide series, a group of 15 similar elements between lant ...

. By 1874, Cleve discovered that thorium was a quadrivalent element and also determined lanthanum to be

trivalent In chemistry, the valence (US spelling) or valency (British spelling) of an element is the measure of its combining capacity with other atoms when it forms chemical compounds or molecules. Description The combining capacity, or affinity of an ...

. These findings were initially doubted by the scientific community. Cleve was the first observer of

isomer In chemistry, isomers are molecules or polyatomic ions with identical molecular formulae – that is, same number of atoms of each element – but distinct arrangements of atoms in space. Isomerism is existence or possibility of isomers. Iso ...

ism in platinumamine derivatives. Additionally, Cleve created a method of dating glacial and post-glacial deposits in the

fossil record A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved in ...

. Cleve's PhD dissertation was "Mineral-analytiska under-sökningar". He wrote a paper on

samarium Samarium is a chemical element with symbol Sm and atomic number 62. It is a moderately hard silvery metal that slowly oxidizes in air. Being a typical member of the lanthanide series, samarium usually has the oxidation state +3. Compounds of samar ...

in 1879 and ''The Seasonal Distribution of Atlantic Plankton Organisms'' in 1900. In 1883, he published ''Kemiskt Handlexicon'', which translates to ''Chemical Handbook''. Notable students of Cleve include

Ellen Fries Ellen Fries (23 September 1855 – 31 March 1900) was a Swedish feminist and writer. She became the first female Ph.D. in Sweden in 1883. She was also involved in founding several women's organizations. Biography She born in 1855 at Rödsleg� ...

(the first Swedish woman to earn a PhD) and

Svante Arrhenius Svante August Arrhenius ( , ; 19 February 1859 – 2 October 1927) was a Swedes, Swedish scientist. Originally a physicist, but often referred to as a chemist, Arrhenius was one of the founders of the science of physical chemistry. He received ...

(a winner of the

Nobel Prize The Nobel Prizes ( ; sv, Nobelpriset ; no, Nobelprisen ) are five separate prizes that, according to Alfred Nobel's will of 1895, are awarded to "those who, during the preceding year, have conferred the greatest benefit to humankind." Alfr ...

). Cleve also studied

hydrography Hydrography is the branch of applied sciences which deals with the measurement and description of the physical features of oceans, seas, coastal areas, lakes and rivers, as well as with the prediction of their change over time, for the primary p ...

and

geology Geology () is a branch of natural science concerned with Earth and other astronomical objects, the features or rocks of which it is composed, and the processes by which they change over time. Modern geology significantly overlaps all other Ear ...

Personal life, family, and death

In 1874, Cleve married Carolina Alma "Caralma" Öhbom (known as Alma Cleve), a teacher and author; the couple had three daughters. The first daughter, Astrid Maria Cleve (born 22 January 1875), became a

botanist Botany, also called , plant biology or phytology, is the science of plant life and a branch of biology. A botanist, plant scientist or phytologist is a scientist who specialises in this field. The term "botany" comes from the Ancient Greek wo ...

. His son-in-law and grandson,

Hans von Euler-Chelpin Hans Karl August Simon von Euler-Chelpin (15 February 1873 – 6 November 1964) was a German-born Swedish biochemist. He won the Nobel Prize in Chemistry in 1929 with Arthur Harden for their investigations on the fermentation of sugar and enz ...

and

Ulf von Euler Ulf Svante von Euler (7 February 1905 – 9 March 1983) was a Swedish physiologist and pharmacologist. He shared the Nobel Prize in Physiology or Medicine in 1970 for his work on neurotransmitters. Life Ulf Svante von Euler-Chelpin was born in ...

, both won Nobel Prizes. Cleve was friends with

Thomas Edward Thorpe Sir Thomas Edward Thorpe CB, FRS H FRSE LLD (8 December 1845 – 23 February 1925) was a British chemist. From 1894 to 1909 he was Chief Chemist to the British Government, as Director of the Government Laboratory. Early life and education Th ...

. The second daughter, Agnes Cleve-Jonand (born Agnes Elisabet Cleve) (1876-1951), was a visual artist and pioneer of Modernism in Sweden. The third and last daughter, Célie Brunius (born Gerda Cecilia Afrodite Cleve) (1882-1980), was a journalist. His daughter Agnes was married to illustrator, set designer and artist John Jon-And. His daughter Célie was married to writer August Brunius and was the mother of artist Göran Brunius, journalist Clas Brunius and associate professor Teddy Brunius. The television host and politician

Lisette Schulman Astrid Maria Elisabet "Lisette" Schulman (née Stolpe; 13 June 1951, Karlskoga – 19 February 2015) was a Swedish television host and politician. She was born to Sven Stolpe, an author and Karin Stolpe (née von Euler-Chelpin), a daughter of Ge ...

was his great-granddaughter. Per Teodore Cleve was a supporter of

women's equality Gender equality, also known as sexual equality or equality of the sexes, is the state of equal ease of access to resources and opportunities regardless of gender, including economic participation and decision-making; and the state of valuing d ...

and

, the first Swedish woman to receive a PhD, was one of his students. Cleve began experiencing

pleurisy Pleurisy, also known as pleuritis, is inflammation of the membranes that surround the lungs and line the chest cavity (pleurae). This can result in a sharp chest pain while breathing. Occasionally the pain may be a constant dull ache. Other sy ...

in December 1904 and it affected his heart. He thought that he had recovered by the spring of 1905, and he returned home to Uppsala, Sweden,. but he died there on 18 June 1905.

Awards and legacy

Cleve joined the

Royal Swedish Academy of Sciences The Royal Swedish Academy of Sciences ( sv, Kungliga Vetenskapsakademien) is one of the Swedish Royal Academies, royal academies of Sweden. Founded on 2 June 1739, it is an independent, non-governmental scientific organization that takes special ...

in 1871. He received a

Davy Medal The Davy Medal is awarded by the Royal Society of London "for an outstandingly important recent discovery in any branch of chemistry". Named after Humphry Davy, the medal is awarded with a monetary gift, initially of £1000 (currently £2000). H ...

in 1894 and 1904. The mineral

cleveite Cleveite is an impure radioactive variety of uraninite containing uranium, found in Norway. It has the composition UO2 with about 10% of the uranium substituted by rare-earth elements. It was named after Swedish chemist Per Teodor Cleve. Clevei ...

is named for Cleve.

References

External links

* * {{DEFAULTSORT:Cleve, Per Teodor 1840 births 1905 deaths 19th-century Swedish chemists Burials at Uppsala old cemetery Discoverers of chemical elements Holmium Members of the Royal Swedish Academy of Sciences Scientists from Stockholm Neodymium Praseodymium 19th-century Swedish geologists Swedish people of German descent Thulium Uppsala University alumni Rare earth scientists