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  2. Lone pair - Wikipedia

    en.wikipedia.org/wiki/Lone_pair

    The σ-symmetry lone pair (σ(out)) is formed from a hybrid orbital that mixes 2s and 2p character, while the π-symmetry lone pair (p) is of exclusive 2p orbital parentage. The s character rich O σ(out) lone pair orbital (also notated n O (σ) ) is an ~sp 0.7 hybrid (~40% p character, 60% s character), while the p lone pair orbital (also ...

  3. Non-canonical base pairing - Wikipedia

    en.wikipedia.org/wiki/Non-canonical_base_pairing

    A unique way of identification of base pairs in RNA was incorporated in MC-Annotate [44] by Francois Major. In this algorithm they make use of the positions of the hydrogen atoms as well as lone-pair electrons using suitable molecular mechanics/dynamics force-fields [45] and derive hydrogen bond formation probabilities for them. The final ...

  4. Lewis acids and bases - Wikipedia

    en.wikipedia.org/wiki/Lewis_acids_and_bases

    For example, NH 3 is a Lewis base, because it can donate its lone pair of electrons. Trimethylborane [(CH 3) 3 B] is a Lewis acid as it is capable of accepting a lone pair. In a Lewis adduct, the Lewis acid and base share an electron pair furnished by the Lewis base, forming a dative bond. [1]

  5. Localized molecular orbitals - Wikipedia

    en.wikipedia.org/wiki/Localized_molecular_orbitals

    For instance, the lone pairs of water are usually treated as two equivalent sp x hybrid orbitals, while the corresponding "nonbonding" orbitals of carbenes are generally treated as a filled σ(out) orbital and an unfilled pure p orbital, even though the lone pairs of water could be described analogously by filled σ(out) and p orbitals (for ...

  6. Amine - Wikipedia

    en.wikipedia.org/wiki/Amine

    Amine. In chemistry, amines (/ ə ˈ m iː n, ˈ æ m iː n /, [1] [2] UK also / ˈ eɪ m iː n / [3]) are compounds and functional groups that contain a basic nitrogen atom with a lone pair.Formally, amines are derivatives of ammonia (NH 3 (in which the bond angle between the nitrogen and hydrogen is 107°), wherein one or more hydrogen atoms have been replaced by a substituent such as an ...

  7. Sigma-pi and equivalent-orbital models - Wikipedia

    en.wikipedia.org/wiki/Sigma-pi_and_equivalent...

    The σ-π model differentiates bonds and lone pairs of σ symmetry from those of π symmetry, while the equivalent-orbital model hybridizes them. The σ-π treatment takes into account molecular symmetry and is better suited to interpretation of aromatic molecules ( Hückel's rule ), although computational calculations of certain molecules tend ...

  8. Molecular geometry - Wikipedia

    en.wikipedia.org/wiki/Molecular_geometry

    A water molecule has two pairs of bonded electrons and two unshared lone pairs. Tetrahedral: Tetra-signifies four, and -hedral relates to a face of a solid, so "tetrahedral" literally means "having four faces". This shape is found when there are four bonds all on one central atom, with no extra unshared electron pairs.

  9. Bent's rule - Wikipedia

    en.wikipedia.org/wiki/Bent's_rule

    Bent's rule can be extended to rationalize the hybridization of nonbonding orbitals as well. On the one hand, a lone pair (an occupied nonbonding orbital) can be thought of as the limiting case of an electropositive substituent, with electron density completely polarized towards the central atom.