Inorganic Chemestry

Inorganic chemistryis the study of the synthesis and behavior of inorganic and organometallic compounds. This field covers all chemical compoundsexcept the myriad organic compounds(carbon based compounds, usually containing C-H bonds), which are the subjects of organic chemistry. The distinction between the two disciplines is far from absolute, and there is much overlap, most importantly in the sub-discipline of organometallic chemistry. It has applications in every aspect of the chemical industry–including catalysis, materials science, pigments, surfactants, coatings, medicine, fuel, and agriculture. [ 1 ] Key concepts The structure of the ionic framework in potassium oxide, K2O Many inorganic compoundsare ionic compounds, consisting of cationsand anionsjoined by ionic bonding. Examples of salts (which are ionic compounds) are magnesium chlorideMgCl2, which consists of magnesiumcations Mg2+and chlorideanions Cl−; or sodium oxideNa2O, which consists of sodiumcations Na+and oxideanions O2−. In any salt, the proportions of the ions are such that the electric charges cancel out, so that the bulk compound is electrically neutral. The ions are described by their oxidation stateand their ease of formation can be inferred from the ionization potential(for cations) or from the electron affinity(anions) of the parent elements. Important classes of inorganic salts are the oxides, the carbonates, the sulfatesand the halides. Many inorganic compounds are characterized by high melting points. Inorganic salts typically are poor conductorsin the solid state. Other important features include their solubility in water(see: solubility chart) and ease of crystallization. Where some salts (e.g., NaCl) are very soluble in water, others (e.g., SiO 2) are not. The simplest inorganic reactionis double displacementwhen in mixing of two salts the ions are swapped without a change in oxidation state. In redox reactionsone reactant, theoxidant, lowers its oxidation state and another reactant, thereductant, has its oxidation state increased. The net result is an exchange of electrons. Electron exchange can occur indirectly as well, e.g., in batteries, a key concept in electrochemistry. When one reactant contains hydrogen atoms, a reaction can take place by exchanging protons in acid-base chemistry. In a more general definition, an acid can be any chemical species capable of binding to electron pairs is called a Lewis acid; conversely any molecule that tends to donate an electron pair is referred to as a Lewis base. As a refinement of acid-base interactions, the HSAB theorytakes into account polarizability and size of ions. Inorganic compounds are found in nature as minerals. Soil may contain iron sulfide as pyriteor calcium sulfate as gypsum. Inorganic compounds are also found multitasking as biomolecules: as electrolytes ( sodium chloride), in energy storage ( ATP) or in construction (the polyphosphatebackbone in DNA). The first important man-made inorganic compound was ammonium nitratefor soil fertilization through the Haber process. Inorganic compounds are synthesized for use as catalystssuch as vanadium(V) oxideand titanium(III) chloride, or as reagentsin organic chemistrysuch as lithium aluminium hydride. Subdivisions of inorganic chemistry are organometallic chemistry, cluster chemistryand bioinorganic chemistry. These fields are active areas of research in inorganic chemistry, aimed toward new catalysts, superconductors, and therapies.