Elements in the earths crust

The environmental impact of tin is appreciable, as it is one of the three most enriched metals—only lead and tellurium precede—in the atmospheric particular matter, as compared with the abundance of the element in the earth crust (2.2 ppm). Tin releases to the environment can be methylated by aquatic organisms, yielding organometallic species of toxicity comparable to that of methylated mercury5. 

Potassium is the eighth most abundant element in the Earths crust, which contains about 2.6% potassium, but not in natural elemental form. Potassium is slightly less abundant than sodium. It is found in almost all solids on Earth, in soil, and in seawater, which contains 380 ppm of potassium in solution. Some of the potassium ores are sylvite, carnallite, and polyha-lite. Ore deposits are found in New Mexico, California, Salt Lake in Utah, Germany, Russia, and Israel. Potassium metal is produced commercially by two processes. One is thermochemical distillation, which uses hot vapors of gaseous NaCl (sodium chloride) and KCl (potassium chloride) the potassium is cooled and drained off as molten potassium, and the sodium chloride is discharged as a slag. The other procedure is an electrolytic process similar to that used to produce hthium and sodium, with the exception that molten potassium chloride (which melts at about 770°C) is used to produce potassium metal at the cathode (see figure 4.1). 

Iron is the fourth most abundant element in the Earths crust (about 5%) and is the ninth most abundant element found in the sun and stars in the universe. The core of the Earth is believed to consist of two layers, or spheres, of iron. The inner core is thought to be molten iron and nickel mixture, and the outer core is a transition phase of iron with the molten magma of the Earths mantle. 

Niobium is the 33rd most abundant element in the Earths crust and is considered rare. It does not exist as a free elemental metal in nature. Rather, it is found primarily in several mineral ores known as columbite (Fe, Mn, Mg, and Nb with Ta) and pyrochlore [(Ca, NaljNbjOg (O, OH, F)]. These ores are found in Canada and Brazil. Niobium and tantalum [(Fe, Mn)(Ta, Nbl Og] are also products from tin mines in Malaysia and Nigeria. Niobium... 

Germanium, the 52nd most abundant element in the Earths crust, is widely distributed, but never found in its natural elemental state. It is always combined with other elements, particularly oxygen. 

Helium in the Earth is replaced by the decay of radioactive elements in the Earths crust. Alpha decay produces particles f He ) known as alpha particles, which can become helium atoms after they capture two electrons. This new helium works its way to the surface of the Earth and escapes into the atmosphere where, in time, it escapes into space. 

Neodymium is the third most abundant rare-earth element in the Earths crust (24 ppm). It is reactive with moist air and tarnishes in dry air, forming a coating of Nd O, an oxide with a blue tinge that flakes away, leaving bare metal that then will continue to oxidi2e. 

Samarium is the 39th most abundant element in the Earths crust and the fifth in abundance (6.5 ppm) of all the rare-earths. In 1879 samarium was first identified in the mineral samarskite [(Y, Ce U, Fe) (Nb, Ta, Ti )Ojg]. Today, it is mostly produced by the ion-exchange process from monazite sand. Monazite sand contains almost all the rare-earths, 2.8% of which is samarium. It is also found in the minerals gadolmite, cerite, and samarskite in South Africa, South America, Australia, and the southeastern United States. It can be recovered as a byproduct of the fission process in nuclear reactors. 

Manganese is distributed widely in nature, mostly as oxide, silicate, and carbonate ores. Manganese ores often are found in association with iron ores in small quantities. The element, however, does not occur naturally in native form. Manganese is the twelfth most abundant element in the earths crust. 

Some elements in aquatic systems exist only at low concentrations (pg/L range) in spite of readily soluble minerals. This phenomenon is not always caused by a generally small distribution of the concerned element in the earth crust mineral as for instance with uranium. Possible limiting factors are the formation of new minerals, co-precipitation, incongruent solutions, and the formation of solid-solution minerals (i.e. mixed minerals). 

Carbon is the twelfth most abundant element in the Earths crust, although it accounts for only c.0.08% of the combined lithosphere (see Box 1.2), hydrosphere and atmosphere. Carbon-rich deposits are of great importance to humans, and comprise diamond and graphite (the native forms of carbon), calcium and magnesium carbonates (calcite, limestone, dolomite, marble and chalk) and fossil fuels (gas, oil and coal). Most of these deposits are formed in sedimentary environments, although the native forms of C require high temperature and pressure, associated with deep burial and metamorphism. 

Because the heavier elements are formed in localized areas of the universe, the distribution of these elements is uneven. The elemental composition of the earth, for example, is very different from most of the rest of the universe. Table 18.5 lists the percent abundance of elements in the earths crust, waters, and atmosphere. Note that eleven elements make up over 99% of the planets mass. Some elements that play major roles in our culture and technology—such as copper, tin, zinc and gold—are actually very rare. 

Sodium is a bright, silvery metal that is soft and has a low density. Like potassium and the other alkali metals, it is too reactive—especially with water—to be found as a pure element in nature. Nevertheless, sodium is the sixth most abundant element in the Earths crust, and its compounds play a vital role in nature. For example, seawater is a natural source of salt (NaCl). When water... 

Calcium is the fifth most abundant element in the Earths crust and is also found in living organisms. In humans and other mammals, teeth and bones contain calcium. The shells of marine organisms are made of a compound called calcium carbonate (CaC03). When these organisms die, these shells form coral reefs like those found in the Florida Keys and the Bahamas. Sir Humphrey Davy first isolated and identified calcium in 1808. 

Iron is the fourth most abundant element in the Earths crust. Iron is often found in the minerals hematite, magnetite, and mar-casite. Large deposits of iron-bearing minerals are found primarily in Australia, Canada, France, India, South Africa, and the United States. The iron used in industry comes from these mineral deposits. In addition, the interior of Earth—called the core—is believed to be composed primarily of iron. Earths interior is extremely hot—hot enough to melt iron into a molten state. 

Demayo a (1986) Elements in the earths crust. In Handbook of Chemistry and Physics, 67fh edn, p. F-137. CRC Press, Boca Raton, Florida. 

Titanium is a widely distributed metal and ranks tenth among the most common elements in the earth crust. In the soils, titanium is generally found in the form of titanium dioxide or titanium silicates, and due to its low solubility is practically unavailable for plants. The application of soluble forms of titanium, Ti-chloride, Ti-sulphate or Ti-ascorbate (Titavit), has been proved to be beneficial to the growth and quality of some important agricultural crops [1,2]. 

Abstract Iron being the fourth most abundant element in the earth crust, Te Mossbauer spectroscopy has become a suitable additional technique for the characterization of all kind of soil materials and minerals. However, for that purpose a good knowledge of the spectral behavior of the various minerals is indispensable. In this chapter a review of the most important soil materials and rock-forming minerals is presented. It starts with a description of the Mossbauer spectroscopic features of the iron oxides and hydroxides, which are essentially present in soils and sediments. Further, the Mossbauer spectra from sulfides, sulfates and carbonates are briefly considered. Finally, the Mossbauer features of the typical and most common silicate and phosphate minerals are reported. The chapter ends with some typical examples, iUustrating the use and power of Mossbauer spectroscopy in the characterization of minerals. 

Francium-223, with a half-life of 22 minutes, is the longest-lived isotope of the element. Since then it has been found to occur naturally, but there is probably less than an ounce of the element in the Earths crust at any given time. Francium, by extrapolation from the melting points of the other alkali metals, would most Hkely be a liquid if enough of it could be isolated. So far no weighable quantities of the element have been produced. 

Silicon, the second most abundant element in the earths crust after oxygen, is widely used in the manufacture of siloxane-based materials. Such materials find application as semiconductors, glasses, ceramics, plastics, elastomers, resins, mesoporous molecular sieves, optical fibers, coatings. 

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