inorganic chemistry

inorganic chemistry,

the study of all the elements and their compounds with the exception of carbon and its compounds, which fall under the category of organic chemistryorganic chemistry,
branch of chemistry dealing with the compounds of carbon. While it is only the fourteenth most common element on earth, carbon forms by far the greatest number of different compounds.
..... Click the link for more information. . Inorganic chemistry investigates the characteristics of substances that are not organic, such as nonliving matter and minerals found in the earth's crust. Branches of inorganic chemistry include applications in organic chemistry, bioinorganic chemistry, coordination chemistry, geochemistry, inorganic technology, nuclear science and energy, organometallic compounds, reaction kinetics and mechanisms, solid-state chemistry, and synthetic inorganic chemistry.

Inorganic Chemistry

the science of chemical elements and the simple and complex compounds formed by them (except the compounds of carbon, which, with a few exceptions, are the subject of organic chemistry).

Inorganic chemistry is the most important area of chemistry, the science dealing with the transformation of matter accompanied by changes in composition, properties, and (or) structure. In addition to organic chemistry, inorganic chemistry is most intimately related to other branches of chemistry, including analytical chemistry, colloid chemistry, crystal chemistry, physical chemistry, chemical thermodynamics, electrochemistry, radiochemistry, and chemical physics; the chemistry of organometallic and heteroorganic compounds is at the boundary between inorganic and organic chemistry. Inorganic chemistry is closely related to the geological and mineralogical sciences, particularly geochemistry and mineralogy, as well as to industrial sciences, such as metallurgy, agrochemistry, and the inorganic aspects of chemical engineering. Theoretical concepts and experimental methods of physics are continually used in inorganic chemistry.

History. The history of inorganic chemistry, particularly before the mid-19th century, is closely interwoven with the general history of chemical knowledge. The most important achievements of chemistry at the turn of the 19th century—the establishment of the oxygen theory of combustion and the atomic theory of chemistry and the discovery of the principal laws of stoichiometry—resulted from the study of inorganic substances.

Metals that were encountered in nature as native ores (gold, silver, copper, and mercury) or were easily obtained by heating their oxide ores with coal (copper, tin, and lead), as well as some nonmetals (carbon in the form of coal and diamond; sulfur; and possibly arsenic), were known even in remote antiquity. In the third and second millennia B.C., methods for obtaining iron from ores and preparing glass objects were known in Egypt, India, and China.

The attempt to convert base, “imperfect” metals into noble, “perfect” metals (gold and silver) was the reason for the appearance of alchemy, which predominated from the fourth to the 16th century A.D. The alchemists created the framework for the chemical operations (evaporation, crystallization, filtration, distillation, and sublimation) that today are used for the isolation and purification of compounds, and they were the first to obtain some simple substances (arsenic, antimony, and phosphorus); hydrochloric, sulfuric, and nitric acids; and many salts (sulfates, alum, and ammonium chloride). In the 16th century metallurgy, ceramics, and glassmaking, which border closely on inorganic chemistry, underwent broad development, which may be seen in the works of V. Biringuccio (1540) and G. Agrícola (1556). In the 1530’s, P. A. Paracelsus, who was aware of the therapeutic properties of preparations of gold, mercury, antimony, lead, and zinc, laid the foundation of iatrochemistry, the application of chemistry to medicine. In the 17th century the division of substances studied in chemistry into mineral, vegetable, and animal (noted in the tenth century by the Arab scientist Rhazes) took root—that is, the demarcation of chemistry into inorganic and organic chemistry was initiated.

In 1661, R. Boyle refuted the theory of the four elements and tria prima of which all substances were thought to consist and defined chemical elements as substances that could not be broken down into other substances. In the late 17th century G. Stahl, developing the ideas of J. J. Becher, proposed the hypothesis that, upon roasting and combustion, bodies lose the element of combustibility, or phlogiston. This hypothesis predominated until the end of the 18th century.

The work of M. V. Lomonosov and A. Lavoisier subsequently facilitated the establishment of inorganic chemistry as a science. Lomonosov formulated the law of conservation of mass and motion (1748), defined chemistry as the study of the changes taking place in complex substances, applied atomistic concepts to explain chemical phenomena, proposed a division of substances into organic and inorganic (1752), and showed that the increase in the weight of metals upon roasting takes place through the addition of some portion of air (1756).

Lavoisier refuted the phlogiston theory, demonstrated the role of oxygen in roasting and combustion processes, made concrete the concept of the chemical element, and created the first rational chemical system of notation (1787). In the early 19th century, J. Dalton introduced the atomic theory into chemistry, discovered the law of multiple proportions, and gave the first table of atomic weights of the chemical elements. Gay-Lussac’s laws (1805–08), the law of definite proportions (J. Proust, 1808), and Avogadro’s law (1811) were also discovered at that time.

In the first half of the 19th century, J. Berzelius conclusively confirmed the atomic theory in chemistry. In the mid-19th century the concepts of the atom, the molecule, and equivalents were formulated and delineated by C. Gerhardt and S. Cannizzaro. At that time more than 60 chemical elements were known. The discovery in 1869 of the periodic law and the construction by D. I. Mendeleev of the periodic system of elements solved the problem of rational classification of the elements. On the basis of his discoveries, Mendeleev corrected the atomic weights of many elements and predicted the atomic weight and properties of gallium, germanium, and scandium, which had not yet been discovered. After the discovery of those elements, the periodic law achieved universal acceptance and became the firm scientific basis of chemistry.

At the turn of the 20th century, inorganic chemists were particularly interested in two little-studied areas, metal alloys and complexes. The study of polished and etched steel surfaces under a microscope, begun in 1831 by P. P. Anosov, was continued by H. C. Sorby (1863), D. K. Chernov (1868), and the German scientist A. Martens (from 1878). The study was improved and substantially expanded by the method of thermal analysis (by H. Le Châtelier and F. Osmond in 1887 and by the English scientist W. Roberts-Austen in 1899).

Important research on alloys using new techniques was conducted by N. S. Kurnakov (from 1899) and A. A. Baikov (from 1900) and by their scientific schools. Extensive studies of alloys were conducted in Germany by G. Tammann (from 1903) and his students. The theoretical basis for the study of alloys was provided by the phase rule of J. W. Gibbs.

Systematic studies of complexes undertaken in the 1860’s by C. Blomstrand and the Danish scientist S. J0rgensen were extended in the 1890’s by A. Werner, who proposed the coordination theory, and by N. S. Kurnakov. L. A. Chugaev and his school carried out particularly extensive work in this area in Russia and the USSR.

In the late 19th century, an important event in the history of inorganic chemistry took place; the inert gases were discovered —argon by J. Rayleigh and W. Ramsay in 1894; helium by Ramsay in 1895; krypton, neon, and xenon by the English scientists Ramsay and M. Travers in 1898; and radon by the German scientist F. Dorn in 1900. At Ramsay’s suggestion, Mendeleev added these elements to his periodic system in a special group (Group 0); they were later made part of Group VIII. Even more important was the discovery of the spontaneous radioactivity of uranium by A. Becquerel (1896) and of thorium by M. Sklodowska-Curie and independently by the German scientist G. Schmidt (1898), followed by the discovery of the radioactive elements polonium and radium by M. Sklodowska-Curie and P. Curie (1898). These findings led to the discovery of the existence of isotopes and to the founding of radiochemistry and the theory of atomic structure (E. Rutherford, 1911, and N. Bohr, 1913).

Advances in nuclear physics made possible the synthesis of the transuranium elements, with atomic numbers from 93 to 105. Work on the synthesis of transuranium elements opened up a new era in the history of inorganic chemistry. Research in this area is being conducted in the USSR, the USA, France, and the Federal Republic of Germany.

Research methods. The two major research approaches in inorganic chemistry are those of synthesis and of physicochemical analysis. Synthesis has been practiced since antiquity. Its basis is the conduct of reactions between initial materials and the isolation of the resultant products by distillation, sublimation, crystallization, and filtration. Synthesis is particularly widespread as a technique in the chemistry of complexes.

The method of physicochemical analysis was essentially founded by N. S. Kurnakov and his students and successors. The essence of the method lies in the measurement of various physical properties of systems of two, three, or more components (the temperatures of onset and completion of crystallization, as well as electric conductivity and hardness). The data obtained are illustrated in diagrams showing the variation of properties with composition. Geometric evaluation of the diagrams makes possible evaluation of the composition and nature of the products formed in the system without their isolation and analysis. Physicochemical analysis suggests paths for the synthesis of compounds and gives a scientific basis for the treatment of ores and the preparation of salts, metals, and alloys. Physicochemical analysis has been universally accepted as a leading method of inorganic chemistry.

Modern inorganic chemistry is characterized by a remarkably wide variety of new methods for the study of the structure and properties of compounds and substances. Since the mid-20th century, the greatest attention has been devoted to the study of the atomic and molecular structure of inorganic compounds by means of direct determination of their structure (that is, the arrangement of atoms in a molecule). Such determinations are carried out using methods of crystal chemistry, spectroscopy, X-ray diffraction analysis, nuclear magnetic resonance, nuclear quadrupole resonance, gamma spectroscopy, and electron paramagnetic resonance. Great significance is attached to the determination of industrially important properties and features (mechanical, magnetic, electrical, and optical properties; heat resistance; and reaction to radioactive irradiation). Inorganic chemistry has become a science concerning inorganic materials based primarily on data about the structure of compounds on the atomic and molecular levels.

Advances in inorganic chemistry. Qualitative changes in inorganic chemistry were brought about by the discovery of the transuranium elements, by the efficient isolation (by chromatography and extraction) of the rare earths and other elements that are difficult to isolate in pure form (for example, the platinum group of metals), and by the economical preparation of rare elements and materials composed of them with particular properties or a predetermined set of properties. Progress in the technology of preparation and use of high-purity elements and compounds must also be noted. The production from such materials of single crystals with specific properties (for example, piezoelectrics, dielectrics, semiconductors, superconductors, and laser crystals)—and also their use—has become a special branch of industry. The chemistry of rare elements is developing especially rapidly. The study of the chemistry of inert gases, which were previously considered incapable of chemical reaction, began in the 1960’s. However, many compounds of krypton, xenon, and radon with fluorine, and also oxides of xenon, have been obtained.

A great deal of attention in modern inorganic chemistry is devoted to the study of the chemical bond, which is the most important feature of any chemical compound. Chemical bonds may be “seen” using physical instruments. Crystallographic methods, which are still very labor-intensive, are being replaced by rapid methods using automatic diffractometers in conjunction with electronic computers. This makes possible rapid determination of interatomic distances and evaluation of the electron density in inorganic compounds, thus providing a basis for more complete representation of molecular structure and computation of molecular properties. Even more detailed information on chemical binding may be obtained by means of X-ray spectroscopy. The development of new physical methods and the interpretation of data require the combined work of inorganic chemists, physicists, and mathematicians. Problems of the structure and reactivity of chemical compounds and questions relating to chemical bonding are being examined with increasing success on the basis of the concepts and methods of quantum mechanics.

Inorganic compounds and materials are used under various operating conditions, under vigorous action of the medium (gases and liquids), and under mechanical loads. Thus, the study of the kinetics of inorganic reactions has great significance, especially in the development of new technologies and materials.

Practical applications. Inorganic chemistry is providing new types of fuel for aircraft and space rockets, and also materials that prevent icing of airplanes and landing strips at airports. It is producing new hard and superhard materials for abrasive and cutting tools: the use of compact cubic boron nitride (borazon) in such tools makes possible the working of very hard alloys at temperatures and speeds so high that diamond cutters burn. Among other new products are compositions for fluxes used in welding; complexes used in industry, agriculture, and medicine; construction materials, including lightweight materials (for example, phosphate-based or phosphate-containing materials); semiconductor and laser materials; heat-resistant metal alloys; and new inorganic fertilizers. Inorganic chemistry satisfies the most varied demands of industry. It is developing very rapidly and is one of the most important sources of scientific and technological progress.

Scientific institutions, societies, organizations, and periodical publications. Until 1917, research on inorganic chemistry in Russia was conducted only in the laboratories of the Academy of Sciences and of institutes of higher education (mining, polytechnic, and electrotechnical institutes in St. Petersburg and universities in St. Petersburg, Moscow, Kazan, Kiev, and Odessa). In 1918 the Institute of Physicochemical Analysis (founded by N. S. Kurnakov) and the Institute for the Study of Platinum and Other Noble Metals (founded by L. A. Chugaev) began to function under the auspices of the Academy of Sciences in Petrograd. In 1934 both institutes and the Laboratory of General Chemistry of the Academy of Sciences of the USSR were combined to form the Institute of General and Inorganic Chemistry of the Academy of Sciences of the USSR (it was named after N. S. Kurnakov in 1944). Aspects of inorganic chemistry are examined at congresses of the International Union of Pure and Applied Chemistry, which has a section for inorganic chemistry, and at meetings of national chemical societies, including the D. I. Mendeleev Chemical Society.

Papers on inorganic chemistry were published during the 18th and 19th centuries (and continue to be published) in chemical journals, as well as in publications of national academies of sciences, universities, technical institutes, and scientific research institutes. In 1892, in connection with the rapid development of inorganic chemistry, the journal Zeitschrift für anorganische Chemie (since 1915, Zeitschrift für anorganische und allgemeine Chemie) was founded in Germany. The journal Inorganic Chemistry has been published in the USA since 1962. In the USSR, articles on inorganic chemistry were published in Izvestiia Instituta fiziko-khimicheskogo analiza (Proceedings of the Institute of Physicochemical Analysis; since 1935, Proceedings of the Sector . . . ), and Izvestiia Instituía po izucheniiu platiny i drugikh blagorodnykh metallov (Proceedings of the Institute for the Study of Platinum and Other Noble Metals; since 1935, Proceedings of the Sector . . . ), both of which were established in 1919. In 1956, these publications were combined to form Zhurnal neorganicheskoi khimii (Journal of Inorganic Chemistry).

REFERENCES

Classical works
Mendeleev, D. I. Osnovy khimii, 13th ed., vols. 1–2. Moscow-Leningrad, 1947.
Lavoisier, A. L. Traité élémentaire de chimie, vols. 1–2. Paris, 1789.
Berzelius, J. J. Lehrbuch der Chemie, 5th ed., vols. 1–5. Leipzig, 1847–56.
History
Giua, M. Istoriia khimii. Moscow, 1966. (Translated from Italian.)
Figurovskii, N. A. Ocherk obshchei istorii khimii: Ot drevneishikh vremen do nachala XIX v. Moscow, 1969.
Kuznetsov, V. I. Evolutsiia predstavlenii ob osnovnykh zakonakh khimii. Moscow, 1967.
Solov’ev, Iu. I. Evolutsiia osnovnykh teoreticheskikh problem khimii. Moscow, 1971.
Razvitie obshchei, neorganicheskoi i analiticheskoi khimii v SSSR. Edited by N. M. Zhavoronkov. Moscow, 1967.
Tananaev, I. V. “Osnovnye dostizheniia neorganicheskoi khimii za 50 let Sovetskoi vlasti.” Zhurnal Vsesoiuznogo khimicheskogo obshchestva im. D. I. Mendeleeva, 1967, vol. 12, no. 5.
Figurovskii, N. A. Otkrytie khimicheskikh elementov i proiskhozhdenie ikh nazvanii. Moscow, 1970.
Partington, J. R. A History of Chemistry. Vol. 1, part 1: London, 1970; vols. 2–4, London, 1961–64.
Handbooks
Gmelin, L. Handbuch der anorganischen Chemie, 8th ed., Syst.-Num. 1–70. Berlin, 1924. (Publication continuing.)
Mellor, J. W. A Comprehensive Treatise on Inorganic and Theoretical Chemistry, vols. 1–16. London, 1952–54.
Pascal, P. Nouveau traité de chimie minérale, vols. 1–19. Paris, 1956–63.
Handbooks and materials for higher educational institutions
Nekrasov, B. V. Osnovy obshchei khimii, vols. 1–2. Moscow, 1974.
Remy, H. Kurs neorganicheskoi khimii, vols. 1–2. Moscow, 1963–66. (Translated from German.)
Shchukarev, S. A. Lektsii po obshchemu kursu khimii, vols. 1–2. Leningrad, 1962–64.
Pauling, L. Obshchaia khimiia. Moscow, 1974. (Translated from English.)
Barnard, A. Teoreticheskie osnovy neorganicheskoi khimii. Moscow, 1968. (Translated from English.)
Day, M. , and J. Selbin. Teoreticheskaia neorganicheskaia khimiia, 2nd ed. Moscow, 1971. (Translated from English.)
Cotton, F. , and G. Wilkinson. Sovremennaia neorganicheskaia khimiia, parts 1–2. Moscow, 1969. (Translated from English.)
Monographs and collections of articles
Rukovodstvo po preparativnoi neorganicheskoi khimii. Edited by G. Brauer. Moscow, 1956. (Translated from German.)
Fizicheskie melody issledovaniia i svoistva neorganicheskikh soedinenii. Moscow, 1970. (Translated from English.)
Kurnakov, N. S. Vvedenie v fiziko-khimicheskii analiz, 4th ed. Moscow-Leningrad, 1940.
Kurnakov, N. S. Izbr. trudy, vols. 1–3. Moscow, 1960–63.
Anosov, V. Ia., and S. A. Pogodin. Osnovnye nachala fiziko-khimiches-kogo analiza. Moscow-Leningrad, 1947.
Grinberg, A. A. Vvedenie v khimiiu kompleksnykh soedinenii, 3rd ed. Moscow-Leningrad, 1966.
Vdovenko, V. M. Sovremennaia radiokhimiia. Moscow, 1969.

I. V. TANANAEV and S. A. POGODIN