Germanium, Tin, and Copper

Abstract

Germanium, tin, and copper have each played a major role in the development of civilization although at distinctly different periods of history . A German chemist Clemens A. Winkler first isolated Germanium in 1886 from the mineral argyrodite, a mixed sulfide of silver and germanium, and named it after his home country Germany. Today germanium is used in the computer industry (as resistors on computer chips), in fiber optics, solar applications, metallurgy, and chemotherapy. In contrast, the archaeological record shows that tin and copper were components of man-made objects found in Iraq that date back to 9000 BC. The Bronze Age began approximately 3500 bc with the discovery that easily smelted soft copper could be made harder and stronger by alloying with tin. Tin and copper remain important for the manufacture of numerous commercially valuable products including electrical conductors, piping, and antimicrobial agents. Germanium is a semiconducting metal from Group IVA of the periodic table and it forms a series of hydrides, which correspond chemically to the methane series of hydrocarbons and to silanes (silicon series of hydrides). Selected physical and chemical properties of germanium and some of its more common compounds are provided. There are numerous organogermanium compounds. Interest in the organogermanium compounds has centered on their antimicrobial activity and the fact that their mammalian toxicity is considerably lower than the corresponding derivatives of tin or lead. In recent years various germanium compounds, for example, carboxyethyl germanium sesquioxide (Ge-132) and lactate–citrate–germanate, have been sold as nutritional supplements, thereby creating a new exposure pathway for germanium and increasing exposure above levels predicted from industrial uses. Tin is a solid, rather an unreactive metal in Group IVA of the periodic table and has the largest number of stable isotopes of any element. Tin also has a large number of unstable isotopes with half-lives ranging from 2.2 min to 105 years. The physical and chemical properties of tin and some of its compounds are provided. Data are shown for elemental tin, organotin compounds, and some inorganic tin compounds. Copper is located in Group IB of the periodic table and was one of the first metals used by humans. The electrical conductivity and malleability of copper are important commercial properties of the metal. The physical and chemical properties of copper and its related compounds are provided. The adverse health effects associated with copper production may be due to the large amounts of sulfur oxides generated during smelting or because of the impurities, such as arsenic and antimony. Exposure to copper can occur from environmental sources such as food, water from copper pipes, and soil ingestion near copper smelting operations. Keywords: agriculture; copper; environmental impact; exposure assessment; fish; germanium; guidelines; inorganic tin compounds; physical and chemical properties; organotin compounds; production; regulation; renal failure; standards; tin; tin plating; toxic effects; use