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The caveman is a stock character representative of primitive humans in the Paleolithic. The popularization of the type dates to the early 20th century, when Neanderthals were influentially described as " simian " or " ape -like" by Marcellin Boule [ 1 ] and Arthur Keith .
Skeletal structural formula of Vitamin B 12.Many organic molecules are too complicated to be specified by a molecular formula.. The structural formula of a chemical compound is a graphic representation of the molecular structure (determined by structural chemistry methods), showing how the atoms are connected to one another. [1]
In chemistry, valence bond (VB) theory is one of the two basic theories, along with molecular orbital (MO) theory, that were developed to use the methods of quantum mechanics to explain chemical bonding. It focuses on how the atomic orbitals of the dissociated atoms combine to give individual chemical bonds when a molecule is formed.
The most common extension to mean field theory is the nuclear pairing. Nuclei with an even number of nucleons are systematically more bound than those with an odd one. This implies that each nucleon binds with another one to form a pair, consequently the system cannot be described as independent particles subjected to a common mean field.
This glossary of chemistry terms is a list of terms and definitions relevant to chemistry, including chemical laws, diagrams and formulae, laboratory tools, glassware, and equipment. Chemistry is a physical science concerned with the composition, structure, and properties of matter , as well as the changes it undergoes during chemical reactions ...
Superexchange or Kramers–Anderson superexchange interaction, is a prototypical indirect exchange coupling between neighboring magnetic moments (usually next-nearest neighboring cations, see the schematic illustration of MnO below) by virtue of exchanging electrons through a non-magnetic anion known as the superexchange center.
According to molecular orbital theory, molecular orbitals are often modeled by the linear combination of atomic orbitals. In a simple diatomic molecule such as hydrogen fluoride (chemical formula: ), one atom may have many more electrons than the other. A sigma bonding orbital is created between the atomic orbitals with like symmetry.
Marc Antoine Auguste Gaudin's volume diagrams of molecules in the gas phase (1833) In two papers outlining his "theory of atomicity of the elements" (1857–58), Friedrich August Kekulé was the first to offer a theory of how every atom in an organic molecule was bonded to every other atom. He proposed that carbon atoms were tetravalent, and ...