Paul Emile Lecoq de Boisbaudran
Encyclopedia
Paul Émile Lecoq de Boisbaudran (18 April 1838 – 28 May 1912) was a French chemist
known for his discoveries of the chemical element
s gallium
, samarium
and dysprosium
.
. The property of de Boisbaudran was sold; and his father Paul started a wine business at Cognac
. The venture required the energy of the entire family, including young Lecoq. His mother was well educated and taught him history and foreign languages, so he was fluent in English. He also studied some courses of the École Polytechnique
by reading the syllabus and fitted up a modest laboratory, where he began to repeat the experiments which he had read in books. In this laboratory he made most of his early discoveries, including the isolation of gallium.
De Boisbaudran’s early work focused on supersaturation
of solutions. He showed that
supersaturation is destroyed by contact with crystals of an isomorphous
salt, and that it is possible to prepare solutions of anhydrous
salts in a supersaturated condition (1866–1869).
In 1874 he found that octahedral faces are less readily soluble than cubic faces for ammonium alum
crystals. His chief work, however, was in spectroscopy and its application to rare earth element
s. He analysed spectra of 35 elements, using the Bunsen burner
, electric spark or both to induce luminescence
and in this way discovered the lanthanide
s samarium
(1880), dysprosium
(1886) and europium
(1890). He also isolated gadolinium
in 1885, the element which was previously discovered in 1880 by J.C. Galissard de Marignac
.
The most notable work of de Boisbaudran was, however, discovery of gallium. In 1875 he had obtained several milligrams of gallium chloride, extracted from a sample of 52 kg of mineral ore, and found new spectroscopic lines in it. He continued the experiments using several hundred kilograms of zinc ore from the Pyrenees
and in the same year isolated more than one gram of the pure metal by electrolysing a solution of its hydroxide in potassium hydroxide
. Later he prepared 75 grams of gallium using more than 4 tonnes of the ore. De Boisbaudran calculated the atomic weight of gallium as 69.86, close to the currently accepted value of 69.723(1). For this work, he received the cross of the Cross of the Legion of Honour, the Davy Medal
(1879) and the Prix Lacaze of 10,000 francs. He was elected a foreign member of the Royal Society
in 1888. It was later claimed that Lecoq had named the element after himself, since gallus is the Latin translation of the French le coq, but Lecoq denied this in an article of 1877 and asserted that the name originates from Latin for Gaul
, Gallia. The existence of gallium had been predicted during 1871 by Dmitri Mendeleev
, who called it eka-aluminium, and its discovery was a boost for Mendeleev's theory of the periodic table
.
Lecoq contributed more to the development of the periodic classification of elements by proposing, soon after its discovery, that argon
was a member of a new, previously unsuspected, chemical series of elements, later to become known as the noble gas
es. After 1895, family duties and failing health hindered his work. His suffered from anchylosis of the joints and passed away in 1912, at the age of seventy-four.
Chemist
A chemist is a scientist trained in the study of chemistry. Chemists study the composition of matter and its properties such as density and acidity. Chemists carefully describe the properties they study in terms of quantities, with detail on the level of molecules and their component atoms...
known for his discoveries of the chemical element
Chemical element
A chemical element is a pure chemical substance consisting of one type of atom distinguished by its atomic number, which is the number of protons in its nucleus. Familiar examples of elements include carbon, oxygen, aluminum, iron, copper, gold, mercury, and lead.As of November 2011, 118 elements...
s gallium
Gallium
Gallium is a chemical element that has the symbol Ga and atomic number 31. Elemental gallium does not occur in nature, but as the gallium salt in trace amounts in bauxite and zinc ores. A soft silvery metallic poor metal, elemental gallium is a brittle solid at low temperatures. As it liquefies...
, samarium
Samarium
Samarium is a chemical element with the symbol Sm, atomic number 62 and atomic weight 150.36. It is a moderately hard silvery metal which readily oxidizes in air. Being a typical member of the lanthanide series, samarium usually assumes the oxidation state +3...
and dysprosium
Dysprosium
Dysprosium is a chemical element with the symbol Dy and atomic number 66. It is a rare earth element with a metallic silver luster. Dysprosium is never found in nature as a free element, though it is found in various minerals, such as xenotime...
.
Biography
De Boisbaudran belonged to the ancient Protestant nobility of considerable fortune, which, however, disappeared after the revocation of the Edict of NantesEdict of Fontainebleau
The Edict of Fontainebleau was an edict issued by Louis XIV of France, also known as the Revocation of the Edict of Nantes. The Edict of Nantes of 1598, had granted the Huguenots the right to practice their religion without persecution from the state...
. The property of de Boisbaudran was sold; and his father Paul started a wine business at Cognac
Cognac
Cognac is a commune in the Charente department in southwestern France. It is a sub-prefecture of the department.-Geography:Cognac is situated on the river Charente between the towns of Angoulême and Saintes. The majority of the town has been built on the river's left bank, with the smaller right...
. The venture required the energy of the entire family, including young Lecoq. His mother was well educated and taught him history and foreign languages, so he was fluent in English. He also studied some courses of the École Polytechnique
École Polytechnique
The École Polytechnique is a state-run institution of higher education and research in Palaiseau, Essonne, France, near Paris. Polytechnique is renowned for its four year undergraduate/graduate Master's program...
by reading the syllabus and fitted up a modest laboratory, where he began to repeat the experiments which he had read in books. In this laboratory he made most of his early discoveries, including the isolation of gallium.
De Boisbaudran’s early work focused on supersaturation
Supersaturation
The term supersaturation refers to a solution that contains more of the dissolved material than could be dissolved by the solvent under normal circumstances...
of solutions. He showed that
supersaturation is destroyed by contact with crystals of an isomorphous
Isomorphism (crystallography)
In crystallography crystals are described as isomorphous if they are closely similar in shape. Historically crystal shape was defined by measuring the angles between crystal faces with a goniometer...
salt, and that it is possible to prepare solutions of anhydrous
Anhydrous
As a general term, a substance is said to be anhydrous if it contains no water. The way of achieving the anhydrous form differs from one substance to another...
salts in a supersaturated condition (1866–1869).
In 1874 he found that octahedral faces are less readily soluble than cubic faces for ammonium alum
Ammonium alum
Ammonium aluminium sulfate, also known as ammonium alum is a white crystalline double sulfate usually encountered as the dodecahydrate, formula Al2·12H2O. It is used in small amounts in a variety of niche applications...
crystals. His chief work, however, was in spectroscopy and its application to rare earth element
Rare earth element
As defined by IUPAC, rare earth elements or rare earth metals are a set of seventeen chemical elements in the periodic table, specifically the fifteen lanthanides plus scandium and yttrium...
s. He analysed spectra of 35 elements, using the Bunsen burner
Bunsen burner
A Bunsen burner, named after Robert Bunsen, is a common piece of laboratory equipment that produces a single open gas flame, which is used for heating, sterilization, and combustion.- Operation:...
, electric spark or both to induce luminescence
Luminescence
Luminescence is emission of light by a substance not resulting from heat; it is thus a form of cold body radiation. It can be caused by chemical reactions, electrical energy, subatomic motions, or stress on a crystal. This distinguishes luminescence from incandescence, which is light emitted by a...
and in this way discovered the lanthanide
Lanthanide
The lanthanide or lanthanoid series comprises the fifteen metallic chemical elements with atomic numbers 57 through 71, from lanthanum through lutetium...
s samarium
Samarium
Samarium is a chemical element with the symbol Sm, atomic number 62 and atomic weight 150.36. It is a moderately hard silvery metal which readily oxidizes in air. Being a typical member of the lanthanide series, samarium usually assumes the oxidation state +3...
(1880), dysprosium
Dysprosium
Dysprosium is a chemical element with the symbol Dy and atomic number 66. It is a rare earth element with a metallic silver luster. Dysprosium is never found in nature as a free element, though it is found in various minerals, such as xenotime...
(1886) and europium
Europium
Europium is a chemical element with the symbol Eu and atomic number 63. It is named after the continent of Europe. It is a moderately hard silvery metal which readily oxidizes in air and water...
(1890). He also isolated gadolinium
Gadolinium
Gadolinium is a chemical element with the symbol Gd and atomic number 64. It is a silvery-white, malleable and ductile rare-earth metal. It is found in nature only in combined form. Gadolinium was first detected spectroscopically in 1880 by de Marignac who separated its oxide and is credited with...
in 1885, the element which was previously discovered in 1880 by J.C. Galissard de Marignac
Jean Charles Galissard de Marignac
Jean Charles Galissard de Marignac was a Swiss chemist whose work with atomic weights suggested the possibility of isotopes and the packing fraction of nuclei and whose study of the rare earth elements led to his discovery of ytterbium in 1878 and codiscovery of gadolinium in 1880.- Life and work...
.
The most notable work of de Boisbaudran was, however, discovery of gallium. In 1875 he had obtained several milligrams of gallium chloride, extracted from a sample of 52 kg of mineral ore, and found new spectroscopic lines in it. He continued the experiments using several hundred kilograms of zinc ore from the Pyrenees
Pyrenees
The Pyrenees is a range of mountains in southwest Europe that forms a natural border between France and Spain...
and in the same year isolated more than one gram of the pure metal by electrolysing a solution of its hydroxide in potassium hydroxide
Potassium hydroxide
Potassium hydroxide is an inorganic compound with the formula KOH, commonly called caustic potash.Along with sodium hydroxide , this colorless solid is a prototypical strong base. It has many industrial and niche applications. Most applications exploit its reactivity toward acids and its corrosive...
. Later he prepared 75 grams of gallium using more than 4 tonnes of the ore. De Boisbaudran calculated the atomic weight of gallium as 69.86, close to the currently accepted value of 69.723(1). For this work, he received the cross of the Cross of the Legion of Honour, the Davy Medal
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 gift of £1000. The medal was first awarded in 1877 to Robert Wilhelm Bunsen and Gustav Robert Kirchhoff "for...
(1879) and the Prix Lacaze of 10,000 francs. He was elected a foreign member of the Royal Society
Royal Society
The Royal Society of London for Improving Natural Knowledge, known simply as the Royal Society, is a learned society for science, and is possibly the oldest such society in existence. Founded in November 1660, it was granted a Royal Charter by King Charles II as the "Royal Society of London"...
in 1888. It was later claimed that Lecoq had named the element after himself, since gallus is the Latin translation of the French le coq, but Lecoq denied this in an article of 1877 and asserted that the name originates from Latin for Gaul
Gaul
Gaul was a region of Western Europe during the Iron Age and Roman era, encompassing present day France, Luxembourg and Belgium, most of Switzerland, the western part of Northern Italy, as well as the parts of the Netherlands and Germany on the left bank of the Rhine. The Gauls were the speakers of...
, Gallia. The existence of gallium had been predicted during 1871 by Dmitri Mendeleev
Dmitri Mendeleev
Dmitri Ivanovich Mendeleev , was a Russian chemist and inventor. He is credited as being the creator of the first version of the periodic table of elements...
, who called it eka-aluminium, and its discovery was a boost for Mendeleev's theory of the periodic table
Periodic table
The periodic table of the chemical elements is a tabular display of the 118 known chemical elements organized by selected properties of their atomic structures. Elements are presented by increasing atomic number, the number of protons in an atom's atomic nucleus...
.
Lecoq contributed more to the development of the periodic classification of elements by proposing, soon after its discovery, that argon
Argon
Argon is a chemical element represented by the symbol Ar. Argon has atomic number 18 and is the third element in group 18 of the periodic table . Argon is the third most common gas in the Earth's atmosphere, at 0.93%, making it more common than carbon dioxide...
was a member of a new, previously unsuspected, chemical series of elements, later to become known as the noble gas
Noble gas
The noble gases are a group of chemical elements with very similar properties: under standard conditions, they are all odorless, colorless, monatomic gases, with very low chemical reactivity...
es. After 1895, family duties and failing health hindered his work. His suffered from anchylosis of the joints and passed away in 1912, at the age of seventy-four.