Martin Heinrich Klaproth | |
|---|---|
 Engraving byAmbroise Tardieu | |
| Born | (1743-12-01)1 December 1743 Wernigerode,Kingdom of Prussia, Holy Roman Empire |
| Died | 1 January 1817(1817-01-01) (aged 73) Berlin, Kingdom of Prussia |
| Citizenship | Wernigerode |
| Known for | Discovery of uranium, zirconium, and other elements |
| Scientific career | |
| Fields | Chemistry |
Martin Heinrich Klaproth (1 December 1743 – 1 January 1817) was a Germanchemist.[1] He trained and worked for much of his life as anapothecary, moving in later life to the university. His shop became the second-largest apothecary in Berlin, and the most productive artisanal chemical research center in Europe.[2]
Klaproth was a major systematizer ofanalytical chemistry,[3] and an independent inventor ofgravimetric analysis.[4][5] His attention to detail and refusal to ignore discrepancies in results led to improvements in the use of apparatus. He was a major figure in understanding the composition of minerals and characterizing the elements.[4] Klaproth discovereduranium (1789)[6] andzirconium (1789). He was also involved in the discovery or co-discovery oftitanium (1795),strontium (1793),cerium (1803), andchromium (1797) and confirmed the previous discoveries oftellurium (1798) andberyllium (1798).[7][8]
Klaproth was a member and director of theBerlin Academy of Sciences.[2] He was recognized internationally as a member of theRoyal Society in London,[9] theInstitut de France, and theRoyal Swedish Academy of Sciences.[10]
Klaproth was born inWernigerode.[1] He was the son of atailor, and attended the Latin school at Wernigerode for four years.[2]
For much of his life he followed the profession ofapothecary. In 1759, when he was 16 years old, he apprenticed at Quedlinburg. In 1764, he became a journeyman. He trained in pharmacies atQuedlinburg (1759–1766);Hanover (1766–1768, withAugust Hermann Brande); Berlin (1768); andDanzig (1770).[2]
In 1771, Klaproth returned to Berlin to work forValentin Rose the Elder as manager of his business. Following Rose's death, Klaproth passed the required examinations to become senior manager. Following his marriage in 1780, he was able to buy his own establishment, the Apotheke zum Baren. Between 1782 and 1800, Klaproth published 84 papers based on researches carried out in the Apotheke's laboratory. His shop was the most productive site of artisanal chemistry investigations in Europe at that time.[2]
Beginning in 1782, he was the assessor of pharmacy for the examining board of the Ober-Collegium Medicum. In 1787 Klaproth was appointed lecturer inchemistry to thePrussian Royal Artillery.[11][7][2]
In 1788, Klaproth became an unsalaried member of the Berlin Academy of Sciences. In 1800, he became the salaried director of the Berlin Academy of Sciences. He sold the apothecary and moved to the academy, where he convinced the university to build a new laboratory. Upon completion in 1802, Klaproth moved the equipment from his apothecary laboratory into the new building.[2]When theUniversity of Berlin was founded in 1810 he was selected to be the professor of chemistry.[11]
He died in Berlin on New Year's Day in 1817.[1]
An exact and conscientious worker, Klaproth did much to improve and systematise the processes ofanalytical chemistry andmineralogy. His appreciation of the value of quantitative methods led him to become one of the earliest adherents of theLavoisierian doctrines outside France.[11][4]
Klaproth was the first to discoveruranium, identifying it first intorbernite but doing the majority of his research on it with the mineralpitchblende.[4][8] On 24 September 1789 he announced his discovery to the Royal Prussian Academy of sciences in Berlin.[12][13] He also discoveredzirconium in 1789,[14][8] separating it in the form of its "earth" zirconia, oxide ZrO2.[15] Klaproth analyzed a brightly-colored form of the mineral called "hyacinth" from Ceylon. He gave the new element the name zirconium based on its Persian name "zargun", gold-colored.[16]: 515
Klaproth characterised uranium and zirconium as distinctelements, though he was unable to isolate them.[8]
Klaproth independently discoveredcerium (1803), arare earth element, around the same time asJöns Jacob Berzelius andWilhelm Hisinger, in the winter of 1803.[17]
William Gregor of Cornwall was the first to identify the elementtitanium in 1791, correctly concluding that he had found a new element in the oreilmenite from the Menachan valley. He proposed the name "menachanite", but his discovery attracted little attention.[16]: 497 Klaproth verified the presence of an oxide of an unknown element in the orerutile from Hungary in 1795. Klaproth suggested the name "titanium". It was later determined that menachanite and titanium were the same element, from two different minerals, and Klaproth's name was adopted.[18]
Klaproth clarified the composition of numerous substances until then imperfectly known, including compounds of then newly recognised elementstellurium,strontium andchromium.[2]Chromium was discovered in 1797 byLouis Nicolas Vauquelin and independently discovered in 1798 by Klaproth and byTobias Lowitz, in a mineral from the Ural mountains.[16]: 578–580 Klaproth confirmed chromium's independent status as an element.[8][19][20][2]
The existence oftellurium was first suggested in 1783 byFranz-Joseph Mueller von Reichenstein, an Austrian mining engineer who was examining Transylvanian gold samples. Tellurium was also discovered independently by HungarianPál Kitaibel in 1789. Mueller sent some of his mineral to Klaproth in 1796. Klaproth isolated the new substance and confirmed the identification of the new elementtellurium in 1798. He credited Mueller as its discoverer, and suggested that theheavy metal be named "tellus", Latin for 'earth'.[21][22][8][23][16]: 1067 [24]: 12–16
In 1790Adair Crawford andWilliam Cruickshank determined that the mineralstrontianite, found nearStrontian in Scotland, was different from barium-based minerals.[25] Klaproth was one of several scientists involved in the characterization ofstrontium compounds and minerals.[26] Klaproth,Thomas Charles Hope, andRichard Kirwan independently studied and reported on the properties of strontianite, the preparation of compounds of strontium, and their differentiation from those of barium. In September 1793, Klaproth published on the separation of strontium frombarium, and in 1794 on the preparation of strontium oxide and strontium hydroxide.[8][26] In 1808,Humphry Davy became the first to successfully isolate the pure element.[27][28]
Louis Nicolas Vauquelin reported the existence of a new element common to emerald and beryl in 1798, and suggested that it be named "glucine". Klaproth confirmed the presence of a new element, and became involved in a lengthy and ongoing debate over its name by suggesting "beryllia". The element was first isolated in 1828, independently byFriedrich Wöhler andAntoine Bussy. Only in 1949 didIUPAC rule exclusively in favor of the nameberyllium.[23][8][16]: 348–352 [24][29]
Klaproth published extensively, collecting over 200 papers by himself inBeiträge zur chemischen Kenntnis der Mineralkörper (5 vols., 1795–1810) andChemische Abhandlungen gemischten Inhalts (1815). He also published aChemisches Wörterbuch (1807–1810), and edited a revised edition ofF. A. C. Gren'sHandbuch der Chemie (1806).
Klaproth became a foreign member of theRoyal Society of London[9] in 1795,[30] and a foreign member of theRoyal Swedish Academy of Sciences in 1804.[10]He also belonged to theInstitut de France.[10]
The craterKlaproth on theMoon is named after him.[31]
In 1823, botanistCarl Sigismund Kunth published a genus offlowering plants (belonging to the familyLoasaceae), from Central America asKlaprothia in his honour.[32]
His sonJulius was a famousorientalist.[33]
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