Minerals chemical reactivity

Sodium is not found ia the free state ia nature because of its high chemical reactivity. It occurs naturally as a component of many complex minerals and of such simple ones as sodium chloride, sodium carbonate, sodium sulfate, sodium borate, and sodium nitrate. Soluble sodium salts are found ia seawater, mineral spriags, and salt lakes. Principal U.S. commercial deposits of sodium salts are the Great Salt Lake Seades Lake and the rock salt beds of the Gulf Coast, Virginia, New York, and Michigan (see Chemicals frombrine). Sodium-23 is the only naturally occurring isotope. The six artificial radioisotopes (qv) are Hsted ia Table 1 (see Sodium compounds). 

Adsorption and Surface Chemical Grafting. As with siHca and many other siHcate minerals, the surface of asbestos fibers exhibit a significant chemical reactivity. In particular, the highly polar surface of chrysotile fibers promotes adsorption (physi- or chemisorption) of various types of organic or inorganic substances (22). Moreover, specific chemical reactions can be performed with the surface functional groups (OH groups from bmcite or exposed siHca). 

Conceivably, many compounds of inorganic elements have chemical reactivity that could contribute to improved adhesion to mineral surfaces. A fairly wide range of compounds, not restricted to any particular group in the periodic table, have been proposed as coupling agents as is shown in the following list ... 

Chemical Reactivity - Reactivity with Water No reaction Reactivity with Common Materials Aluminum, copper, brass, lead, zinc salts, mineral acids, oxidizing or reducing agents all can cause rapid decomposition Stability During Transport Unstable, slowly evolves oxygen Inhibitor of Polymerization Not pertinent.. 

The thermodynamics treatment followed in this volume strongly reflects our backgrounds as experimental research chemists who have used chemical thermodynamics as a base from which to study phase stabilities and thermodynamic properties of nonelectrolytic mixtures and phase properties and chemical reactivities in metals, minerals, and biological systems. As much as possible, we have attempted to use actual examples in our presentation. In some instances they are not as pretty as generic examples, but real-life is often not pretty. However, understanding it and its complexities is beautiful, and thermodynamics provides a powerful probe for helping with this understanding. 

Many years ago, geochemists recognized that whereas some metallic elements are found as sulfides in the Earth s crust, others are usually encountered as oxides, chlorides, or carbonates. Copper, lead, and mercury are most often found as sulfide ores Na and K are found as their chloride salts Mg and Ca exist as carbonates and Al, Ti, and Fe are all found as oxides. Today chemists understand the causes of this differentiation among metal compounds. The underlying principle is how tightly an atom binds its valence electrons. The strength with which an atom holds its valence electrons also determines the ability of that atom to act as a Lewis base, so we can use the Lewis acid-base model to describe many affinities that exist among elements. This notion not only explains the natural distribution of minerals, but also can be used to predict patterns of chemical reactivity. 

Improve adhesion of dissimilar materials such as polymers to inorganic substrates. Also called primers. Primers generally contain a multifunctional chemically reactive species capable of acting as a chemical bridge. In theory, any polar functional group in a compound may contribute to improved bonding to mineral surfaces. However, only a few organofunc-tional silanes have the balance of characteristics required... 

Bailey G.W., Akim L.G., Shevchenko S.M. Predicting chemical reactivity of humic substances for minerals and xenobiotics use of computational chemistry, scanning probe microscopy, and virtual reality. In Humic Substances and Chemical Contaminants, C.E. Clapp, M.H.B. Hayes, N. Senesi, P.R. Bloom, P.M. Jardine, eds. Madison, WI Soil Science Society of America, Inc., 2001. 

A possible explanation for the preference of living systems for the L (levorotatory) over the D (dextrorotatory) optical isomer may be associated with the stereoselective properties of layered minerals. To test this hypothesis, the rates of L- and D-histidine intercalation into HT layered compound was investigated using the pressure-jump relaxation technique (21). The rate constants and interlayer spacing based on this investigation are summarized in Table V. As shown the slightly enhanced rate for L-histidine suggests that relative chemical reactivity may be associated with natural selection of the L-form of amino acids in nature. 

Al, Ga, In and T1 differ sharply from boron. They have greater chemical reactivity at lower temperatures, well-defined cationic chemistry in aqueous solutions they do not form numerous volatile hydrides and cluster compounds as boron. Aluminium readily oxidizes in air, but bulk samples of the metal form a coherent protective oxide film preventing appreciable reaction aluminium dissolves in dilute mineral acids, but it is passivated by concentrated HN03. It reacts with aqueous NaOH, while gallium, indium and thallium dissolve in most acids. 

S (3p), and Cu (3d) orbit, respectively. According to the frontier orbital theory, the electrons in the highest occupied state are most easily bound and have an imexpectedly great significance for the chemical reactivity of materials. It indicates that the different reduction or oxidation would happen on the three mineral surfaces in the pulp during flotation system. 

Geochemistry of Mineral Surfaces and Factors Affecting Their Chemical Reactivity... 

The purpose of this chapter is to present a brief overview of the geochemistry of mineral surfaces, including their (1) dissolution mechanisms, (2) development of electrical charge when in contact with aqueous solutions, and (3) uptake of aqueous cations and anions, and to discuss some of the factors that control their chemical reactivity, including (1) defect density, (2) cooperative effects among adsorbates,... 

We begin with a discussion of the most common minerals present in Earth s crust, soils, and troposphere, as well as some less common minerals that contain common environmental contaminants. Following this is (1) a discussion of the nature of environmentally important solid surfaces before and after reaction with aqueous solutions, including their charging behavior as a function of solution pH (2) the nature of the electrical double layer and how it is altered by changes in the type of solid present and the ionic strength and pH of the solution in contact with the solid and (3) dissolution, precipitation, and sorption processes relevant to environmental interfacial chemistry. We finish with a discussion of some of the factors affecting chemical reactivity at mineral/aqueous solution interfaces. 

Factors affecting the chemical reactivity of mineral surfaces... 

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