Chalcogenadiazoles : chemistry and applications Preface This book considers the chemical biomedical and technical importance of chalcogenadiazoles. These compounds contain five membered cycles composed of two carbons two nitrogens and one chalcogen the latter as the key heteroatom. Chalcogens are chemical elements of VIA group of the periodic system namely oxygen (O) sulfur (S) selenium (Se) tellurium (Te) and polonium (Po). At present all chalcogenadiazoles are known naturally except for the polonium species. The external shells of the O S Se and Te atoms have s2p4 configuration. These elements are isovalent. As the atomic number increases covalent and ionic radii increase and ionization energies decrease. At first glance some similarities between analogously constructed chalcogenadiazoles might be expected. At a narrower glance the fundamental properties of the key atoms in chalcogenadiazoles vary significantly and these differences can lead to disparities between the molecules under consideration. The number of different chalcogenadiazoles and their structural diversity make it difficult to gain a good understanding of the subject by studying an individual class of these hetrocycles. The book tries to identify and emphasize general features of this family of heterocycles. The combined presence of the mentioned atoms endows heterocyclic systems with some specific properties. The book concentrates on properties of each class of chalcogenadiazoles and their cycle fused derivatives considering chemical reactions of functional groups only in cases when these properties permit to characterize the heterocycles as substituents or in respect of its aromaticity. Nitrogen oxides and chalcogen oxides of these heterocycles are equally discussed A timely and authoritative treatise on the chemistry and diverse applications of chalcogenadiazoles the five membered rings containing two carbons two nitrogens and one chalcogen (an member of group 16 the oxygen family).The number of different chalcogenadiazoles and their structural diversity make it difficult to gain a clear understanding of the subject by studying an individual system in isolation. Chalcogenadiazoles: Chemistry and Applications emphasizes general features of this class of heterocyclic compounds. It concentrates on properties of each class of chalcogenadiazoles and their cycle fused derivatives considering chemical reactions of functional groups only in cases when these reactions permit to characterize the heterocycles as substituents or in respect of its aromaticity.Covering an important and rapidly developing branch of heterocyclic chemistry this book is an essential resource for students young professionals and experienced specialists in adjacent fields who are interested in:Trends in the search for compounds with established bioactivity or use in medicine as agrochemicals or as reagents for environmental and biochemical analysis Differences in classes of chalcogenadiazoles with respect to their degree of aromaticity and similar general concepts helpful to the nonspecialistThe effects of the chalcogen nature and the alternation manner of all atomic constituents on properties of these heterocyclic compoundsCombining data from organic biological medicinal materials science and supramolecular chemistry Chalcogenadiazoles: Chemistry and Applications is an important source of information not only for chemists in the fields of organic inorganic and organometallic chemistry but also for anyone interested in the research and development of chalcogenadiazoles and related species