Thenard

Ar. Buraq, Pers. Burah) Boron compounds have been known for thousands of years, but the element was not discovered until 1808 by Sir Humphry Davy and by Gay-Lussac and Thenard. 

L. silex, silicis, flint) Davy in 1800 thought silica to be a compound and not an element later in 1811, Gay Lussac and Thenard probably prepared impure amorphous silicon by heating potassium with silicon tetrafluoride. 

The salts have been used for centuries to produce brilliant and permanent blue colors in porcelain, glass, pottery, tiles, and enamels. It is the principal ingredient in Sevre s and Thenard s blue. A solution of the chloride is used as a sympathetic ink. Cobalt carefully used in the form of the chloride, sulfate, acetate, or nitrate has been found effective in correcting a certain mineral deficiency disease in animals. 

Boron trifluoride [7637-07-2] (trifluoroborane), BF, was first reported in 1809 by Gay-Lussac and Thenard (1) who prepared it by the reaction of boric acid and fluorspar at duU red heat. It is a colorless gas when dry, but fumes in the presence of moisture yielding a dense white smoke of irritating, pungent odor. It is widely used as an acid catalyst (2) for many types of organic reactions, especially for the production of polymer and petroleum (qv) products. The gas was first produced commercially in 1936 by the Harshaw Chemical Co. (see also Boron COMPOUNDS). 

Stannous fluoride probably was first prepared by Scheele in 1771 and was described by Gay-Lussac and Thenard in 1809. Commercial production of stannous fluoride is by the reaction of stannous oxide and aqueous hydrofluoric acid, or metallic tin and anhydrous hydrogen fluoride (5,6). Snp2 is also produced by the reaction of tin metal, HP, and a halogen in the presence of a nitrile (7). 

Silicon [7440-21-3] Si, from the Latin silex, silicis for flint, is the fourteenth element of the Periodic Table, has atomic wt 28.083, and a room temperature density of 2.3 gm /cm. SiUcon is britde, has a gray, metallic luster, and melts at 1412°C. In 1787 Lavoisier suggested that siUca (qv), of which flint is one form, was the oxide of an unknown element. Gay-Lussac and Thenard apparently produced elemental siUcon in 1811 by reducing siUcon tetrafluoride with potassium but did not recognize it as an element. In 1817 BerzeHus reported evidence of siUcon occurring as a precipitate in cast iron. Elemental siUcon does not occur in nature. As a constituent of various minerals, eg, siUca and siUcates such as the feldspars and kaolins, however, siUcon comprises about 28% of the earth s cmst. There are three stable isotopes that occur naturally and several that can be prepared artificially and are radioactive (Table 1) (1). 

Thenard blue blue-greens blue-black black... 

Hydrogen peroxide was first made in 1818 by J. L. Thenard who acidified barium peroxide (p. 121) and then removed excess H2O by evaporation under reduced pressure. Later the compound was prepared by hydrolysis of peroxodisulfates obtained by electrolytic oxidation of acidified sulfate solutions at high current densities ... 

During the first third of the nineteenth centuiy, several systematic obseiwations led researchers to conclude that the mere presence of metals induced chemical transformations in fluids that would otherwise not have occurred. Early on, Thenard had... 

History. The first known peroxide to be produced was Ba02 as described by A. Humboldt in 1799. Later, G. Gay-Lussac and L. Thenard synthesized Na and K peroxides, and Thenard synthesized H202 in 1818 (Ref 17)... 

According to Vpl nov, the historical development of inorganic peroxide chemistry can be divided into four periods. The fust period, from 1818 (Thenard s synthesis of H202) to 1869 (the formulation of the Periodic Table by D.I. Mendele eff) is characterized by the wide-ranging investigations conducted by Thenard and his co-workers concerning the reaction of oxidized water which resulted in the development of a whole series of peroxide derivs as well as a more precise determination of the structure of Na peroxide... 

Gay-Lussac JL, Thenard JL (1809) Mem Phys Chim Soc d Arcueil 2 210 as cited in Jonas G, Frenking G (1994) J Chem Soc Chem Common 1989... 

Joseph Louis Gay-Lussac (1778-1850) and Louis Jacques Thenard (1777-1857). 

Boron (Buraq in Arabic/Burah in Persian, which is the word for white, the color being attributed to borax (sodium tetraborate, Na2B4O7.10H2O)) was discovered in 1808 independently by the British Chemist, Sir Humphry Davy, and two French chemists, Joseph Louis Gay-Lussac and Loius Jacques Thenard.1 They isolated boron in 50% purity by the reduction of boric acid with sodium or magnesium. The Swedish chemist Jons Jakob Berzilius identified boron as an element in 1824. The first pine sample of boron was produced by the American chemist William Weintraub in 1909. Boron does not appear in nature in elemental form, but is found in its compounded... 

Thenard, J., Compt. rend., 1844, 18, 652 A mixture with excess oxide can be exploded by sparking. 

Alexander von Humboldt (1769-1859) recognised meteorites as being a source of extraterrestrial material. Several well-known chemists carried out analyses of material from meteorites, starting at the beginning of the nineteenth century. Thus Louis-Jacques Thenard (1777-1857) found carbon in Alais meteorites these results were confirmed in 1834 by Jons Jacob Berzelius, who by dint of very careful work was also able to detect water of crystallisation in meteoritic material. 

Boron itself was first produced in 1808 by Sir Humphrey Davy, who carried out the electrolysis of molten boric acid. The reduction of boric acid by potassium was used as a preparative method by Gay-Lussac and Thenard in 1808, and reduction of B203 by magnesium was the method used by Moissan in 1895. 

Thenard A process for making white lead pigment (basic lead carbonate) by boiling litharge (lead monoxide) with lead acetate solution and passing carbon dioxide gas into the suspension. 

Ecole Polytechnique, the Institute of Egypt, and the suburban Arcueil estates of Laplace and Berthollet. Like Gay-Lussac, the chemists Louis N. Vauquelin, Michel Eugene Chevreul, and Louis Jacques Thenard admitted well-recommended students to their private chemical laboratories. By the 1830s, Dumas and Victor Regnault were training students in larger numbers as part of the expected chemical curriculum. 84... 

Boron (B, [He]2.v22p1), name and symbol from the Persian word burah and the Arabic word buraq (borax). The suffix-on was added because of the similarity to carbon. Discovered (1808) by J.-L. Gay-Lussac and L.J. Thenard in France and Humphry Davy in England. 

Boron - the atomic number is 5 and the chemical symbol is B. The name derives from the Arabic buraq for white . Although its compounds were known for thousands of years, it was not isolated until 1808 when the French chemists Louis-Joseph Gay-Lussac and Louis-Jacques Thenard obtained boron in an impure state and the English chemist, Humphry Davy, prepared pure boron by electrolysis. 

In 1808 two French chemists, Joseph Louis Gay-Lussac (1778-1850) and Louis-Jacques Thenard (1777-1857), experimented along the same lines as Davy and should also be given some credit for the discovery of these elements. The Frenchmen named the new element bore, and Davy called it boracium. ... 

Boron B 1808 (London England and Paris, France) Sir Humphry Davy (British) and Joseph Gay-Lussac, Louis Thenard (both French) 175... 

British chemist Sir Humphry Davy and French chemists Joseph-Louis Gay-Lussac, Louis-Jacques Thenard Nearly as hard as diamond, this brittle crystal is rare in pure form combines to form borax also valuable in the production of glass and semiconductors. 

---