Amalgam (dentistry) and 900 shares of tin." Ever since its introduction in the Western world in the 1830s, amalgam has been the subject of recurrent controversies because of its mercury content. Early amalgam was made by mixing mercury with the filings of silver coins. In 1833 Englishmen, Edward Crawcour and his nephew Moses Crawcour (incorrectly referred to as "the Crawcour brothers"), brought amalgam to the United States, and in 1844 it was reported that fifty percent of all dental restorations placed in upstate New York consisted of amalgam. However, at that point the use of dental amalgam was declared to be malpractice,
Inorganic chemistry based on their properties. Partly the classification focuses on the position in the periodic table of the heaviest element (the element with the highest atomic weight) in the compound, partly by grouping compounds by their structural similarities. When studying inorganic compounds, one often encounters parts of the different classes of inorganic chemistry (an organometallic compound is characterized by its coordination chemistry, and may show interesting solid state properties). Different classifications are: Classical coordination compounds feature metals bound to "lone pairs" of electrons residing on the main group atoms of ligands such as HO, NH, Cl, and CN. In modern coordination