Chemistry during 19th century

It has been known for centuries that codistillation of many plant materials with steam produces a fragrant mixture of liquids called essential oils. For hundreds of years, such plant extracts have been used as medicines, spices, and perfumes. The investigation of essential oils also played a major role in the emergence of organic chemistry as a science during the 19th century. 

Metal complexes (complex compounds or coordination compounds) are one of the most important groups of chemical compounds and form the basis of coordination chemistry. Although complex compounds date back to the 18th century, coordination chemistry was considered a science only after the formulation of the coordination theory by the Swiss chemist A. Werner at the end of the 19th century [1], During the 20th century, thousands of metal complexes were obtained, characterized, and widely applied. Much has been written on heir synthesis, structure, and properties [2-13],... 

The role of the early work on chemical kinetics in the evolution of physical chemistry has been examined with reference to van t Hoff s, Ostwald s, and Harcourt s researches prior to the 1880s.123 There is also a discussion of chemical kinetics and thermodynamics during the 19th century,124 and an analysis of the relation of chemical kinetics and physical chemistry up to the early part of the 20th century.125 Studies have been made of the role of instruments and the specific laboratory locales for chemical kinetics in the interwar years,126 and the work of H. Eyring127 and J.-A. Muller128 in chemical kinetics has been analysed. 

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