120 relations: Acetic acid, Alexander Nesmeyanov, Alkene, Alkylation, Allyl group, Allylic rearrangement, Aniline, Arene substitution pattern, Aromaticity, Arrow pushing, August Kekulé, Avoided crossing, Ångström, Benzene, Benzoic acid, Biphenylene, Bond length, Bond order, Butyl group, Carbocation, Carboxylate, Chemical equilibrium, Chemistry, Christopher Kelk Ingold, Conjugate acid, Conjugated system, Covalent bond, Cyclohexane, Cyclohexene, Delocalized electron, Dialectical materialism, Diborane, Diene, Dimethylaniline, Double bond, Electromerism, Electron density, Electronegativity, Elementary charge, Enthalpy, Erich Hückel, Excited state, Exothermic process, Formal charge, Frequency, Friedel–Crafts reaction, Fritz Arndt, Furan, Harmonic oscillator, Hydrochloric acid, ..., Hydrogen bromide, Hydrogen iodide, Hydrogenation, Hydroxylamine, Hyperconjugation, Hypervalent molecule, International Union of Pure and Applied Chemistry, Isomer, Johannes Thiele (chemist), John C. Slater, Leviathan, Lewis structure, Linear combination of atomic orbitals, Linus Pauling, Lone pair, Mathematical optimization, Mesomeric effect, Methanium, Molecular orbital, Molecular orbital theory, Molecule, Multiplicity (chemistry), Narwhal, Natural bond orbital, Nitrate, Nitrite, Nitronium ion, Node (physics), Normalizing constant, Nuclear magnetic resonance, Octet rule, Orbital hybridisation, Ozone, Pauling's principle of electroneutrality, Perchlorate, Perchloric acid, Phenol, Pi bond, Picometre, Picric acid, Polar effect, Polyatomic ion, Polycyclic aromatic hydrocarbon, Propylamine, Pyridine, Quantum mechanics, Radical (chemistry), Resonance, Spin (physics), Spin isomers of hydrogen, Substituent, Superacid, Tautomer, Thiocyanate, Three-center two-electron bond, Triazabicyclodecene, Triphenylphosphine, Triple bond, Unicorn, Valence bond theory, Valence electron, Variational principle, Wave function, Werner Heisenberg, X-ray crystallography, Xenon difluoride, 1,3-Cyclohexadiene, 1,8-Diazabicyclo(5.4.0)undec-7-ene, 2,4-Dinitrophenol, 2-Norbornyl cation. Expand index (70 more) » « Shrink index
Acetic acid, systematically named ethanoic acid, is a colourless liquid organic compound with the chemical formula CH3COOH (also written as CH3CO2H or C2H4O2).
Alexander Nikolaevich Nesmeyanov (Александр Николаевич Несмеянов;, Moscow – 17 January 1980, Moscow) was a prominent Soviet chemist and academician (1943) specializing in organometallic chemistry.
In organic chemistry, an alkene is an unsaturated hydrocarbon that contains at least one carbon–carbon double bond.
Alkylation is the transfer of an alkyl group from one molecule to another.
An allyl group is a substituent with the structural formula H2C.
An allylic rearrangement or allylic shift is an organic reaction in which the double bond in an allyl chemical compound shifts to the next carbon atom.
Aniline is an organic compound with the formula C6H5NH2.
Arene substitution patterns are part of organic chemistry IUPAC nomenclature and pinpoint the position of substituents other than hydrogen in relation to each other on an aromatic hydrocarbon.
In organic chemistry, the term aromaticity is used to describe a cyclic (ring-shaped), planar (flat) molecule with a ring of resonance bonds that exhibits more stability than other geometric or connective arrangements with the same set of atoms.
Arrow pushing or electron pushing is a technique used to describe the progression of organic chemistry reaction mechanisms.
Friedrich August Kekulé, later Friedrich August Kekule von Stradonitz (7 September 1829 – 13 July 1896), was a German organic chemist.
In quantum physics and quantum chemistry, an avoided crossing (sometimes called intended crossing, non-crossing or anticrossing) is the phenomenon where two eigenvalues of an Hermitian matrix representing a quantum observable and depending on N continuous real parameters cannot become equal in value ("cross") except on a manifold of N-2 dimensions.
The ångström or angstrom is a unit of length equal to (one ten-billionth of a metre) or 0.1 nanometre.
Benzene is an important organic chemical compound with the chemical formula C6H6.
Benzoic acid, C7H6O2 (or C6H5COOH), is a colorless crystalline solid and a simple aromatic carboxylic acid.
Biphenylene is an alternant, polycyclic hydrocarbon composed of two benzene rings joined together by a pair of mutual attachments (as opposed to a normal ring fusion), thus forming a 6-4-6 arene system.
In molecular geometry, bond length or bond distance is the average distance between nuclei of two bonded atoms in a molecule.
Bond order is the number of chemical bonds between a pair of atoms.
In organic chemistry, butyl is a four-carbon alkyl radical or substituent group with general chemical formula −C4H9, derived from either of the two isomers of butane.
A carbocation (/karbɔkətaɪː'jɔ̃/) is an ion with a positively charged carbon atom.
A carboxylate is a salt or ester of a carboxylic acid.
In a chemical reaction, chemical equilibrium is the state in which both reactants and products are present in concentrations which have no further tendency to change with time, so that there is no observable change in the properties of the system.
Chemistry is the scientific discipline involved with compounds composed of atoms, i.e. elements, and molecules, i.e. combinations of atoms: their composition, structure, properties, behavior and the changes they undergo during a reaction with other compounds.
Sir Christopher Kelk Ingold (28 October 1893 – 8 December 1970) was a British chemist based in Leeds and London.
A conjugate acid, within the Brønsted–Lowry acid–base theory, is a species formed by the reception of a proton (H+) by a base—in other words, it is a base with a hydrogen ion added to it.
In chemistry, a conjugated system is a system of connected p-orbitals with delocalized electrons in molecules which are conventionally represented as having alternating single and multiple bonds, which in general may lower the overall energy of the molecule and increase stability.
A covalent bond, also called a molecular bond, is a chemical bond that involves the sharing of electron pairs between atoms.
Cyclohexane is a cycloalkane with the molecular formula C6H12 (the alkyl is abbreviated Cy).
Cyclohexene is a hydrocarbon with the formula C6H10.
In chemistry, delocalized electrons are electrons in a molecule, ion or solid metal that are not associated with a single atom or a covalent bond.
Dialectical materialism (sometimes abbreviated diamat) is a philosophy of science and nature developed in Europe and based on the writings of Karl Marx and Friedrich Engels.
Diborane is the chemical compound consisting of boron and hydrogen with the formula B2H6.
In organic chemistry a diene or diolefin is a hydrocarbon that contains two carbon double bonds.
N,N-Dimethylaniline (DMA) is an organic chemical compound, a substituted derivative of aniline.
A double bond in chemistry is a chemical bond between two chemical elements involving four bonding electrons instead of the usual two.
Electromerism is a type of isomerism between a pair of molecules (electromers, electro-isomers) differing in the way electrons are distributed among the atoms and the connecting chemical bonds.
Electron density is the measure of the probability of an electron being present at a specific location.
Electronegativity, symbol ''χ'', is a chemical property that describes the tendency of an atom to attract a shared pair of electrons (or electron density) towards itself.
The elementary charge, usually denoted as or sometimes, is the electric charge carried by a single proton, or equivalently, the magnitude of the electric charge carried by a single electron, which has charge.
Enthalpy is a property of a thermodynamic system.
Erich Armand Arthur Joseph Hückel (August 9, 1896, Berlin – February 16, 1980, Marburg) was a German physicist and physical chemist.
In quantum mechanics, an excited state of a system (such as an atom, molecule or nucleus) is any quantum state of the system that has a higher energy than the ground state (that is, more energy than the absolute minimum).
In thermodynamics, the term exothermic process (exo-: "outside") describes a process or reaction that releases energy from the system to its surroundings, usually in the form of heat, but also in a form of light (e.g. a spark, flame, or flash), electricity (e.g. a battery), or sound (e.g. explosion heard when burning hydrogen).
In chemistry, a formal charge (FC) is the charge assigned to an atom in a molecule, assuming that electrons in all chemical bonds are shared equally between atoms, regardless of relative electronegativity.
Frequency is the number of occurrences of a repeating event per unit of time.
The Friedel–Crafts reactions are a set of reactions developed by Charles Friedel and James Crafts in 1877 to attach substituents to an aromatic ring.
Fritz Georg Arndt (6 July 1885 – 8 December 1969) was a German chemist recognised for his contributions to synthetic methodology, who together with Bernd Eistert discovered the Arndt-Eistert synthesis.
Furan is a heterocyclic organic compound, consisting of a five-membered aromatic ring with four carbon atoms and one oxygen.
In classical mechanics, a harmonic oscillator is a system that, when displaced from its equilibrium position, experiences a restoring force, F, proportional to the displacement, x: where k is a positive constant.
Hydrochloric acid is a colorless inorganic chemical system with the formula.
Hydrogen bromide is the diatomic molecule with the formula.
Hydrogen iodide is a diatomic molecule and hydrogen halide.
Hydrogenation – to treat with hydrogen – is a chemical reaction between molecular hydrogen (H2) and another compound or element, usually in the presence of a catalyst such as nickel, palladium or platinum.
Hydroxylamine is an inorganic compound with the formula NH2OH.
In organic chemistry, hyperconjugation is the interaction of the electrons in a sigma orbital (e.g. C–H or C–C) with an adjacent empty (or partially filled) non-bonding orbital, antibonding σ or π orbital, to give an extended molecular orbital.
A hypervalent molecule (the phenomenon is sometimes colloquially known as expanded octet) is a molecule that contains one or more main group elements apparently bearing more than eight electrons in their valence shells.
The International Union of Pure and Applied Chemistry (IUPAC) is an international federation of National Adhering Organizations that represents chemists in individual countries.
An isomer (from Greek ἰσομερής, isomerès; isos.
Friedrich Karl Johannes Thiele (May 13, 1865 – April 17, 1918) was a German chemist and a prominent professor at several universities, including those in Munich and Strasbourg.
John Clarke Slater (December 22, 1900 – July 25, 1976) was a noted American physicist who made major contributions to the theory of the electronic structure of atoms, molecules and solids.
Leviathan is a sea monster referenced in the Hebrew Bible in the Book of Job, Psalms, the Book of Isaiah, and the Book of Amos.
Lewis structures, also known as Lewis dot diagrams, Lewis dot formulas, Lewis dot structures, electron dot structures, or Lewis electron dot structures (LEDS), are diagrams that show the bonding between atoms of a molecule and the lone pairs of electrons that may exist in the molecule.
A linear combination of atomic orbitals or LCAO is a quantum superposition of atomic orbitals and a technique for calculating molecular orbitals in quantum chemistry.
Linus Carl Pauling (February 28, 1901 – August 19, 1994) was an American chemist, biochemist, peace activist, author, educator, and husband of American human rights activist Ava Helen Pauling.
In chemistry, a lone pair refers to a pair of valence electrons that are not shared with another atomIUPAC Gold Book definition: and is sometimes called a non-bonding pair.
In mathematics, computer science and operations research, mathematical optimization or mathematical programming, alternatively spelled optimisation, is the selection of a best element (with regard to some criterion) from some set of available alternatives.
The mesomeric effect in chemistry is a property of substituents or functional groups in a chemical compound.
In chemistry, methanium is a complex positive ion with formula +, namely a molecule with one carbon atom bonded to three hydrogen atoms and one hydrogen molecule, bearing a +1 electric charge.
In chemistry, a molecular orbital (MO) is a mathematical function describing the wave-like behavior of an electron in a molecule.
In chemistry, molecular orbital (MO) theory is a method for determining molecular structure in which electrons are not assigned to individual bonds between atoms, but are treated as moving under the influence of the nuclei in the whole molecule.
A molecule is an electrically neutral group of two or more atoms held together by chemical bonds.
In spectroscopy and quantum chemistry, the multiplicity of an energy level is defined as 2S+1, where S is the total spin angular momentum.
The narwhal (Monodon monoceros), or narwhale, is a medium-sized toothed whale that possesses a large "tusk" from a protruding canine tooth.
In quantum chemistry, a natural bond orbital or NBO is a calculated bonding orbital with maximum electron density.
Nitrate is a polyatomic ion with the molecular formula and a molecular mass of 62.0049 u.
The nitrite ion, which has the chemical formula, is a symmetric anion with equal N–O bond lengths.
The nitronium ion,, is a cation.
A node is a point along a standing wave where the wave has minimum amplitude.
The concept of a normalizing constant arises in probability theory and a variety of other areas of mathematics.
Nuclear magnetic resonance (NMR) is a physical phenomenon in which nuclei in a magnetic field absorb and re-emit electromagnetic radiation.
The octet rule is a chemical rule of thumb that reflects observation that atoms of main-group elements tend to combine in such a way that each atom has eight electrons in its valence shell, giving it the same electron configuration as a noble gas.
In chemistry, orbital hybridisation (or hybridization) is the concept of mixing atomic orbitals into new hybrid orbitals (with different energies, shapes, etc., than the component atomic orbitals) suitable for the pairing of electrons to form chemical bonds in valence bond theory.
Ozone, or trioxygen, is an inorganic molecule with the chemical formula.
Pauling's principle of electroneutrality states that each atom in a stable substance has a charge close to zero.
A perchlorate is the name for a chemical compound containing the perchlorate ion,.
Perchloric acid is a mineral acid with the formula HClO4.
Phenol, also known as phenolic acid, is an aromatic organic compound with the molecular formula C6H5OH.
In chemistry, pi bonds (π bonds) are covalent chemical bonds where two lobes of an orbital on one atom overlap two lobes of an orbital on another atom.
The picometre (international spelling as used by the International Bureau of Weights and Measures; SI symbol: pm) or picometer (American spelling) is a unit of length in the metric system, equal to, or one trillionth of a metre, which is the SI base unit of length.
Picric acid is an organic compound with the formula (O2N)3C6H2OH.
The polar effect or electronic effect in chemistry is the effect exerted by a substituent on modifying electrostatic forces operating on a nearby reaction center.
A polyatomic ion, also known as a molecular ion, is a charged chemical species (ion) composed of two or more atoms covalently bonded or of a metal complex that can be considered to be acting as a single unit.
Polycyclic aromatic hydrocarbons (PAHs, also polyaromatic hydrocarbons or polynuclear aromatic hydrocarbons) are hydrocarbons—organic compounds containing only carbon and hydrogen—that are composed of multiple aromatic rings (organic rings in which the electrons are delocalized).
Propylamine, also known as n-propylamine, is an amine with the chemical formula C2H5CH2NH2 (also written as C3H7NH2 and C3H9N).
Pyridine is a basic heterocyclic organic compound with the chemical formula C5H5N.
Quantum mechanics (QM; also known as quantum physics, quantum theory, the wave mechanical model, or matrix mechanics), including quantum field theory, is a fundamental theory in physics which describes nature at the smallest scales of energy levels of atoms and subatomic particles.
In chemistry, a radical (more precisely, a free radical) is an atom, molecule, or ion that has an unpaired valence electron.
In physics, resonance is a phenomenon in which a vibrating system or external force drives another system to oscillate with greater amplitude at specific frequencies.
In quantum mechanics and particle physics, spin is an intrinsic form of angular momentum carried by elementary particles, composite particles (hadrons), and atomic nuclei.
Molecular hydrogen occurs in two isomeric forms, one with its two proton nuclear spins aligned parallel (orthohydrogen), the other with its two proton spins aligned antiparallel (parahydrogen).
In organic chemistry and biochemistry, a substituent is an atom or group of atoms which replaces one or more hydrogen atoms on the parent chain of a hydrocarbon, becoming a moiety of the resultant new molecule.
According to the classical definition, a superacid is an acid with an acidity greater than that of 100% pure sulfuric acid, which has a Hammett acidity function (H0) of −12.
Tautomers are constitutional isomers of organic compounds that readily interconvert.
Thiocyanate (also known as rhodanide) is the anion −. It is the conjugate base of thiocyanic acid.
A three-center two-electron bond is an electron-deficient chemical bond where three atoms share two electrons.
Triphenylphosphine (IUPAC name: triphenylphosphane) is a common organophosphorus compound with the formula P(C6H5)3 - often abbreviated to PPh3 or Ph3P.
A triple bond in chemistry is a chemical bond between two atoms involving six bonding electrons instead of the usual two in a covalent single bond.
The unicorn is a legendary creature that has been described since antiquity as a beast with a single large, pointed, spiraling horn projecting from its forehead.
In chemistry, valence bond (VB) theory is one of two basic theories, along with molecular orbital (MO) theory, that were developed to use the methods of quantum mechanics to explain chemical bonding.
In chemistry, a valence electron is an outer shell electron that is associated with an atom, and that can participate in the formation of a chemical bond if the outer shell is not closed; in a single covalent bond, both atoms in the bond contribute one valence electron in order to form a shared pair.
A variational principle is a scientific principle used within the calculus of variations, which develops general methods for finding functions which extremize the value of quantities that depend upon those functions.
A wave function in quantum physics is a mathematical description of the quantum state of an isolated quantum system.
Werner Karl Heisenberg (5 December 1901 – 1 February 1976) was a German theoretical physicist and one of the key pioneers of quantum mechanics.
X-ray crystallography is a technique used for determining the atomic and molecular structure of a crystal, in which the crystalline atoms cause a beam of incident X-rays to diffract into many specific directions.
Xenon difluoride is a powerful fluorinating agent with the chemical formula, and one of the most stable xenon compounds.
1,3-Cyclohexadiene is an organic compound with the formula (CH2)2(CH)4.
1,8-Diazabicycloundec-7-ene, or more commonly DBU, is a chemical compound and belongs to the class of amidine compounds.
2,4-Dinitrophenol (2,4-DNP or simply DNP) is an organic compound with the formula HOC6H3(NO2)2.
In organic chemistry, the term 2-norbornyl cation (equivalent with 2-bicyclo-heptyl cation) describes one of the three carbocations formed from derivatives of norbornane.
Canonical form (chemistry), Chemical resonance, Delocalization energy, Hybrid structure, Mesomer, Mesomerism, Molecular resonance, Resonance (molecular structure), Resonance Hybrid, Resonance contribution, Resonance contributor, Resonance effect, Resonance energy, Resonance form, Resonance hybrid, Resonance stabilization, Resonance stabilized, Resonance structure, Resonance structures, Resonance-stabilized, Theory of Resonance.