Siberian red lead

Johann Gottlieb Lehmann was mining director in Prussia and a teacher in Berlin. In 1761 he was employed as professor of chemistry in St Petersburg. He was appointed by Catherine herself to travel through the empire and describe mineralogical discoveries that could be of interest for technical and economic development The area round Yekaterinburg was subject to great activity as also were areas further east. 

The achievements of Lehmarui and PaUas made the red Siberian mineral known and accessible to better equipped laboratories in Europe. 

From the Outskirts of the French Revolution to the Center of Chemistry 

Fourcroy himself had grown up under poor circumstances and was thrown upon his own resources of talent and dihgence to fulfil his advanced studies. He was successful and was at 30 elected a member of the Academie des Science. He became an enthusiastic teacher of chemistry and he found in Vauquehn an equally enthusiastic pupil and assistant. In addition, Fourcroy s two unmarried sisters saw it as their mis- 

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Chromium was first isolated and identified as a metal in 1789 by Vauquelin who was working with a rare mineral, Siberian red lead or crocoite [14654-05-08] PbCrO (3). The name chromium comes from the Greek word chroma color and resulted from the wide variety of brilliant colors... 

Nicolas Louis Vauquelin (1763-1829) discovers the element during the analysis of Siberian red lead ore J (PbCr04). 

Shrink-resist science/technology development of, 26 391 Shrink-resist treatments, 26 391-393 additive, 26 393 chlorine-based, 26 392 chlorine-free, 26 392-393 Shuiskite, 6 471t Shutdown period, 29 494 Shutdown systems, 20 671-672 Shuttle vectors, 26 482-483 Sialon-bonded silicon carbide, 22 541 Siberian red lead, 6 468 S-iB-S block copolymers, 24 707 SiC-ceramic, 22 525. See also Silicon carbide... 

Historically, chromium ore was known as Siberian red lead, which was used to make bright red paints. The source was soon identified as the mineral crocoite, and analysis indicated that it also contained lead. In 1797 the French chemist Louis-Nicolas Vauquelin (1763—1829) discovered chromium while studying some minerals that were collected in Siberia. To isolate the pure metal from its oxide, he first dissolved the lead out of the mineral with hydrochloric acid (HCl), leaving crystals of chromium oxide, which he then heated. To his surprise he ended up with crystals of pure chromium metal. 

The beautiful red colour, transparency, and crystalline figure of the Siberian red lead, continued Vauquelin, soon induced mineralogists... 

Peter Simon Pallas, 1741-1811, German scientist who made extensive scientific journeys to study the natural history of Russia and Siberia. He described the Beresof gold mines and the Siberian red lead (crocoite) in 1770. 

Among the other early investigators of crocoite (Siberian red lead) were Count Apollos Apollosovich Musin-Pushkin0 (1760-1805), Tobias Lowitz (Tovii Egorovich Lovits) (1757-1804), and M. H. Klaproth (82). Count Musin-Pushkin s analyses were made with portable equipment during one of his mineralogical journeys (82). 

Chromium was discovered in a mineral known as Siberian red lead. The mineral was first described in 1766 by German mineralogist Johann... 

Studies of Siberian red lead were difficult, however. It was mined at only one location in Germany and miners found it difficult to remove. Scientists had only small amounts of the mineral to study. They guessed that it contained lead as well as arsenic, molybdenum, or some other metal. 

In 1797, Vauquelin began his own studies of Siberian red lead. He was convinced that the mineral contained a new element. None of the elements then known could account for his results. He reported finding a new metal, possessing properties entirely unlike those of any other metal. ... 

Chromium as a metallic element was first discovered two hundred years ago, in 1797. But the history of chromium really began several decades before this. In 1761, in the Beresof Mines of the Ural Mountains Johann Gottlob Lehmann obtained samples of an orange-red mineral, which he called Siberian red lead . He analyzed this mineral in 1766 and discovered that it contained lead mineralised with a selenitic spar and iron particles. The mineral he found was crocoite, a lead chromate (PbCr04). 

Chromium was first identified in 1797 by the French chemist Louis-Nicolas Vauquelin, who isolated it from crocoite, a mineral also called Siberian red lead. The name for chromium is taken from the Greek chroma, which means color. This is a fitting name, because chromium compounds are often found in vividly colorful shades of green, red, or yellow. As such, chromium compounds historically have found extensive use as pigments for paints. In contrast, elemental chromium is a shiny, hard, yet brittle, steel-gray metal. Since chromium is not found naturally in its free elemental state, it is usually extracted from chromite, FeCr204. 

Discovery The mineral Siberian red lead , crocoite, a lead chromate, was discovered by Lehmann in the 1760s in the Beresof Mine, Ural Mountains. In 1770 the mineral was again found there and characterized by Pallas. The red lead was investigated and a new metal, chromium, was isolated in 1797 by Nicolas-Louis Vauquelin in Paris. The technically important mineral chromite was discovered in 1798 in the Ural Mountains. 

In 1797 VauqueHn got a sample of Siberian red lead for investigation. He began with a recapitulation of its history He pointed out that all specimens of the substance in different mineral coUections in Europe came from one single place, the Beresof gold mine. 

Siberian red lead. Chrome red is Pb CrOj, lead oxide chromate. In our day the use of color pigments containing lead and hexavalent chromium is of course restricted for environmental reasons. 

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