Metals abundance

Of the five Group III elements, only boron and aluminium are reasonably familiar elements. Aluminium is in fact the most abundant metal, the third most abundant element in nature, but the other elements are rare and boron is the only one so far found In concentrated deposits. 

Aluminium is not found free but its compounds are so widespread that it is the most abundant metal in the earth s crust. Aluminosilicates such as clay, kaolin (or china clay), mica and feldspar are well known and widely distributed. The oxide. AI2O3. occurs (anhydrous) as corundum and emery, and (hydrated) as bauxite. Cryolite. Na,AlF. (sodium hexafluoroaluminate). is found extensively in Greenland. 

After aluminium, iron is the most abundant metal and the fourth most abundant of all the elements it occurs chiefly as oxides (for example haematite (FCjO,), magnetite (lodestonej (FC3O4) and as iron pyrites FeSj- Free iron is found in meteorites, and it is probable that primitive man used this source of iron for tools and weapons. The extraction of iron began several thousand years ago, and it is still the most important metal in everyday life because of its abundance and cheapness, and its ability to be cast, drawn and forged for a variety of uses. 

Aluminum can now be produced from clay, but the process is not economically feasible at present. Aluminum is the most abundant metal to be found in the earth s crust (8.1%), but is never found free in nature. In addition to the minerals mentioned above, it is found in granite and in many other common minerals. 

Sodium, 22 700 ppm (2.27%) is the seventh most abundant element in crustal rocks and the fifth most abundant metal, after Al, Fe, Ca and Mg. Potassium (18 400 ppm) is the next most abundant element after sodium. Vast deposits of both Na and K salts occur in relatively pure form on all continents as a result of evaporation of ancient seas, and this process still continues today in the Great Salt Lake (Utah), the Dead Sea and elsewhere. Sodium occurs as rock-salt (NaCl) and as the carbonate (trona), nitrate (saltpetre), sulfate (mirabilite), borate (borax, kemite), etc. Potassium occurs principally as the simple chloride (sylvite), as the double chloride KCl.MgCl2.6H2O (camallite) and the anhydrous sulfate K2Mg2(S04)3 (langbeinite). There are also unlimited supplies of NaCl in natural brines and oceanic waters ( 30kgm ). Thus, it has been calculated that rock-salt equivalent to the NaCl in the oceans of the world would occupy... 

Calcium, as noted above, is the fifth most abundant element in the earth s crust and hence the third most abundant metal after A1 and Fe. Vast sedimentary deposits of CaC03, which represent the fossilized remains of earlier marine life, occur over large parts of the earth s surface. The deposits are of two main... 

The nuclei of iron are especially stable, giving it a comparatively high cosmic abundance (Chap. 1, p. 11), and it is thought to be the main constituent of the earth s core (which has a radius of approximately 3500 km, i.e. 2150 miles) as well as being the major component of siderite meteorites. About 0.5% of the lunar soil is now known to be metallic iron and, since on average this soil is 10 m deep, there must be 10 tonnes of iron on the moon s surface. In the earth s crustal rocks (6.2%, i.e. 62000ppm) it is the fourth most abundant element (after oxygen, silicon and aluminium) and the second most abundant metal. It is also widely distributed. 

Aluminum is the most abundant metallic element in the Earth s crust and, after oxygen and silicon, the third most abundant element (see Fig. 14.1). However, the aluminum content in most minerals is low, and the commercial source of aluminum, bauxite, is a hydrated, impure oxide, Al203-xH20, where x can range from 1 to 3. Bauxite ore, which is red from the iron oxides that it contains (Fig. 14.23), is processed to obtain alumina, A1203, in the Bayer process. In this process, the ore is first treated with aqueous sodium hydroxide, which dissolves the amphoteric alumina as the aluminate ion, Al(OH)4 (aq). Carbon dioxide is then bubbled through the solution to remove OH ions as HCO and to convert some of the aluminate ions into aluminum hydroxide, which precipitates. The aluminum hydroxide is removed and dehydrated to the oxide by heating to 1200°C. 

Iron, Fe, the most widely used of all the d-metals, is the most abundant element on Earth and the second most abundant metal in the Earth s crust (after aluminum). Its principal ores are the oxides hematite, Fe203, and magnetite, Fc C)4. The sulfide mineral pyrite, FeS2 (see Fig. 15.11), is widely available, but it is not used in steelmaking because the sulfur is difficult to remove. 

Iron is the second most abundant metal on earth. It is a group 8 and period 4 element with [Ar] 3cf4s as electronic configuration. Iron as a metal is rarely found because it oxidizes readily in the presence of oxygen and moisture. Hence, it forms salts in its preferred oxidation state +2 and +3. 

Precious metals have faced a significant price increase and the fear of depletion. By contrast, iron is a highly abundant metal in the crust of the earth (4.7 wt%) of low toxicity and price. Thus, it can be defined as an environmentally friendly material. Therefore, iron complexes have been studied intensively as an alternative for precious-metal catalysts within recent years (for reviews of iron-catalyzed organic reactions, see [12-20]). The chemistry of iron complexes continues to expand rapidly because these catalysts play indispensable roles in today s academic study as well as chemical industry. 

Different minerals contain different metal cations to balance the -4 charge on the orthosilicate ion. Examples Include calcium silicate (Ca2 Si04), an important ingredient in cement, and zircon (ZrSi04), which is often sold as artificial diamond. One of the most prevalent minerals in the Earth s mantle is olivine, Af2(Si04), in which M is one or two of the abundant metal cations, Fe -, Mg -, and Mn +. 

Aluminum is the third most abundant element in the Earth s cmst and the most abundant metal. Nevertheless, aluminum was not discovered until 1825 and was still a precious rarity 60 years later. The reason for this elusiveness is the high stability of Al. The reduction of aluminum compounds to the free... 

The extraction of metals fundamentally relies on their availability in nature. Three terms are important while one refers to availability. One is the crustal abundance and the other two are the terms resources and reserves. The average crustal abundance of the most abundant metals, aluminum, iron and magnesium, are 8.1%, 5.0% and 2.1% respectively. Among the rare metals titanium is the most abundant, constituting 0.53% of the Earth s crust No metal can be economically extracted from a source in which its concentration is the same... 

Iron is one of the most abundant metals in the upper crust of the earth. It is the fourth mineral-forming element (after silicon, oxygen, and aluminum), constituting about 5% of the earth s crust (see Table 1). Large deposits of its ores are numerous, widely distributed, and easily accessible. 

Iron is the second most abundant metal on the planet. Probably due to its abundance, virtually all forms of life have evolved to depend on iron to support essential biological processes, which include a range of catalytic processes, electron transfer, and small molecule storage and transport (1). However, ferric... 

Titanium is the most abundant metal in the earth crust, and is present in excess of 0.62%. It can be found as dioxy titanium and the salts of titanium acids. Titanium is capable of forming complex anions representing simple titanites. It can also be found in association with niobium, silicates, zircon and other minerals. A total of 70 titanium minerals are known, as mixtures with other minerals and also impurities. Only a few of these minerals are of any economic importance. 

We can see the rise of heavy metal groundwater contents in the southward direction with increasing content of total soluble salts. However, this increase is not similar for various metals. For example, Zn is the most abundant metal in the waters of Tundra... 

For most living bacteria (lactobacilli being the only notable exception [154]) iron is an essential nutrient. Iron is not readily available under normal conditions, although it is the fourth most abundant metal on earth. In the environment it is mainly found as a component of insoluble hydroxides in biological systems it is chelated by high-affinity iron binding proteins (e.g. transferrins,... 

Iron, element 26 in the periodic table, is the fourth most abundant element of the earth s crust and, after aluminium, the second most abundant metal. In the middle of the first transition... 

Silicon is the most abundant metal-like element in the earth s crust. It is seldom present in pure elemental form, but is rather found in a large number of polymers based largely on the polycondensation of the orthosilicate anion, SiO as illustrated in the following equations ... 

Crude oil consists mainly of a mixture of paraffinic, naphthenic, and aromatic hydrocarbons with small amounts of metals-containing heterocyclic compounds. The most abundant metals found in oils are those contained in porphyrin or porphyrin-like complexes (nickel, copper, iron, and vanadium). These... 

Found in the ore bauxite is the Earth s most abundant metal industrial use includes many items, from airplanes to soda cans. 

British chemist Sir Humphry Davy Soft, reactive, abundant metal as barium sulfate, it blocks transmission during diagnostic X rays to highlight organs and other tissue. 

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