The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
Osmosis is a phenomenon which regulates many biological functions in plants and animals. That the plants stand upright, or the water reaches the tip of every leaf of a plant is due to osmotic pressure. The fact that we cannot survive by drinking seawater is also linked to this same phenomenon. J H van’ t Hoff showed in 1886 that osmotic pressure is related to concentration and temperature of the solution...
Dinitrogen (N2) is a very stable and inert molecule due to the formation of a triple bond between the two atoms. Surprisingly isoelectronic molecules are quite reactive making dinitrogen very useful and unique.
One of the most important chemical reactions is electron transfer from one atomic/molecular unit to another. This reaction, accompanied by proton and hydrogen atom transfers, occurs in a cascade in many biological processes, including photosynthesis. The key chemical steps involved in photosynthesis and the many unsolved mysteries are described in this article.
All of us have read about solid, liquid and gaseous states of matter in school. Are these the only states of matter? What distinguishes different states of matter from each other?
A simple procedure for determining whether a pericyclic reaction is thermally allowed is described. The focus is on the potential aromaticity of the transition state of the process, wich is inferred from the topological features of the interacting orbitals and the number of electrons involved.
Dendritic macromolecules are excellent examples for macromolecules that possess well-defined branching that develops from a core to the periphery. The pseudospherical structure of dendrimers has opened up numerous possibilities for interesting applications.
V Chandrasekhar is a Professor of Chemistry at the Indian Institute of Technology, Kanpur with research interests in main group organometallic chemistry, inorganic ring systems and inorganic polymers.
The method of isotopic perturbation of equilibrium is described. In conjunction with nuclear magnetic resonance spectroscopy, the procedure can be used to distinguish between double well and single minimum potential energy surfaces. Some representative studies on classical and nonclassical carbocations are discussed.
The concept that all matter is made up of atoms was suggested by Dalton in 1803. It was a very useful concept, which could explain many of the experimental observations, but people were sceptical and considered atoms to be hypothetical objects until the beginning of the 20th century. By the end of the 20th century, advances in science and technology led to imaging of atoms and molecules. Now we are...
Jayant M Modak is Professor and Chairman at the Department of Chemical Engineering, Indian Institute of Science. His research interests include modeling, optimization and control of reactors, engineering analysis of fermentation processes and biohydrometallurgy.
Since the time Cannizzaro expounded a system of atomic weight determination in the Karlsruhe Congress in 1860 [10], and firmly established Avogadro hypothesis, there have been dozens of experimentalmethods for determining theAvogadro number. Many of these methods seek to determine a fundamental physical constant such as charge of an electron or the Boltzmann constant whose value for one mole of particles...
Recently, extremely large benzenoid hydrocarbons have been synthesized. These compounds resemble graphite in many ways, and have been named graphenes. Because of their nonstandard properties, graphenes have already found numerous applications, especially as special-purpose materials in electronics. In this article we outline the basic chemical facts on graphenes.
Gopalpur Nagendrappa teaches organic chemistry at Bangalore University. His work includes organic synthesis and reaction mechanisms mainly in the area of organosilicon chemistry.
Ever since its isolation in 1820, Quinine has played a crucial role in the development of organic chemistry, chemical industry and modern medicine. The total synthesis of quinine, widely regarded as anevent of epochal importancewas claimed by Woodward and Doering in 1945. This work, however, heavily relied on unsubstantiated literature reports and it appears that Woodward’s work fell short of a total...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.