See also: Molecular orbital theory and Molecular orbital diagram
Complete acetylene (H–C≡C–H) molecular orbital set. The left column shows MO's which are occupied in the ground state, with the lowest-energy orbital at the top. The white and grey line visible in some MO's is the molecular axis passing through the nuclei. The orbital wave functions are positive in the red regions and negative in the blue. The right column shows virtual MO's which are empty in the ground state, but may be occupied in excited states.
In chemistry, a molecular orbital (/ɒrbədl/) is a mathematical function describing the location and wave-like behavior of an electron in a molecule. This function can be used to calculate chemical and physical properties such as the probability of finding an electron in any specific region. The terms atomic orbital and molecular orbital[a] were introduced by Robert S. Mulliken in 1932 to mean one-electron orbital wave functions.[2] At an elementary level, they are used to describe the region of space in which a function has a significant amplitude.
In an isolated atom, the orbital electrons' location is determined by functions called atomic orbitals. When multiple atoms combine chemically into a molecule by forming a valence chemical bond, the electrons' locations are determined by the molecule as a whole, so the atomic orbitals combine to form molecular orbitals. The electrons from the constituent atoms occupy the molecular orbitals. Mathematically, molecular orbitals are an approximate solution to the Schrödinger equation for the electrons in the field of the molecule's atomic nuclei. They are usually constructed by combining atomic orbitals or hybrid orbitals from each atom of the molecule, or other molecular orbitals from groups of atoms. They can be quantitatively calculated using the Hartree–Fock or self-consistent field (SCF) methods.
Molecular orbitals are of three types: bonding orbitals which have an energy lower than the energy of the atomic orbitals which formed them, and thus promote the chemical bonds which hold the molecule together; antibonding orbitals which have an energy higher than the energy of their constituent atomic orbitals, and so oppose the bonding of the molecule, and non-bonding orbitals which have the same energy as their constituent atomic orbitals and thus have no effect on the bonding of the molecule.
^ abMulliken, Robert S. (July 1932). "Electronic Structures of Polyatomic Molecules and Valence. II. General Considerations". Physical Review. 41 (1): 49–71. Bibcode:1932PhRv...41...49M. doi:10.1103/PhysRev.41.49.
^Brown, Theodore (2002). Chemistry : the central science. Upper Saddle River, NJ: Prentice Hall. ISBN 0-13-066997-0.
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region. The terms atomic orbital and molecularorbital were introduced by Robert S. Mulliken in 1932 to mean one-electron orbital wave functions. At an elementary...
In chemistry, molecularorbital theory (MO theory or MOT) is a method for describing the electronic structure of molecules using quantum mechanics. It...
In theoretical chemistry, an antibonding orbital is a type of molecularorbital that weakens the chemical bond between two atoms and helps to raise the...
A molecularorbital diagram, or MO diagram, is a qualitative descriptive tool explaining chemical bonding in molecules in terms of molecularorbital theory...
LUMO are types of molecularorbitals. The acronyms stand for highest occupied molecularorbital and lowest unoccupied molecularorbital, respectively. HOMO...
In chemistry, orbital hybridisation (or hybridization) is the concept of mixing atomic orbitals to form new hybrid orbitals (with different energies,...
chemistry, the bonding orbital is used in molecularorbital (MO) theory to describe the attractive interactions between the atomic orbitals of two or more atoms...
atomic orbital is combined in the term. The coefficients are the weights of the contributions of the n atomic orbitals to the molecularorbital. The Hartree–Fock...
In chemistry, frontier molecularorbital theory is an application of molecularorbital theory describing HOMO–LUMO interactions. In 1952, Kenichi Fukui...
shared electron (rather than two); in molecularorbital terms, the third electron is in an anti-bonding orbital which cancels out half of the bond formed...
orbital on one atom overlap with two lobes of an orbital on another atom, and in which this overlap occurs laterally. Each of these atomic orbitals has...
primarily in two molecularorbitals, each with electron density equally distributed among the two O-H bonds. The localized orbital corresponding to one...
The fragment molecularorbital method (FMO) is a computational method that can be used to calculate very large molecular systems with thousands of atoms...
bond or the internuclear axis). Quantum theory also indicates that molecularorbitals (MO) of identical symmetry actually mix or hybridize. As a practical...
has symmetry group D2h, and its highest occupied molecularorbital (HOMO) is the bonding pi orbital which forms a basis for its irreducible representation...
In quantum mechanics, an atomic orbital (/ˈɔːrbɪtəl/) is a function describing the location and wave-like behavior of an electron in an atom. This function...
valence bond (VB) theory is one of the two basic theories, along with molecularorbital (MO) theory, that were developed to use the methods of quantum mechanics...
two non-bonding orbitals, orbital mixing can be further performed between the 2p (3a1) orbital on oxygen and the antibonding 4a1 orbital since they are...
orbitals, sharing the electrons uniformly among all five atoms. There are two orbital levels, a bonding molecularorbital formed from the 2s orbital on...
_{i}n_{i}c_{ri}c_{si}} , Here the sum extends over π molecularorbitals only, and ni is the number of electrons occupying orbital i with coefficients cri and csi on atoms...
single spherical lobe of a hydrogen 1s orbital). Each atomic orbital contributes one electron when the orbitals overlap pairwise to form two-electron σ...
Look up orbital in Wiktionary, the free dictionary. Orbital may refer to: Atomic orbitalMolecularorbital Hybrid orbitalOrbit Earth orbitOrbit (anatomy)...
Likewise, promotion of an electron from a pi-bonding orbital (π) to an antibonding pi orbital (π*) is denoted as a π → π* transition. Auxochromes with...
delocalized over an entire molecule. The Hund–Mulliken approach or molecularorbital (MO) method is less intuitive to chemists, but has turned out capable...
the bonding, orbital arrangement, and other characteristics of coordination complexes. It represents an application of molecularorbital theory to transition...
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