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[1] [2] [3] Introduced by Gilbert N. Lewis in his 1916 article The Atom and the Molecule, a Lewis structure can be drawn for any covalently bonded molecule, as well as coordination compounds. [4] Lewis structures extend the concept of the electron dot diagram by adding lines between atoms to represent shared pairs in a chemical bond.
All charge-neutral boron halides violate the octet rule, hence they typically are Lewis acidic. For example, boron trifluoride (BF 3) combines eagerly with fluoride sources to give the tetrafluoroborate anion, BF 4 −. Boron trifluoride is used in the petrochemical industry as a catalyst. The halides react with water to form boric acid. [51]
Lewis dot diagram structures show three formal alternatives for describing bonding in boron monofluoride. BF is unusual in that the dipole moment is inverted with fluorine having a positive charge even though it is the more electronegative element. This is explained by the 2sp orbitals of boron being reoriented and having a higher electron density.
Introduced by J. W. Linnett in his 1961 monograph [1] and 1964 book, [2] this method expands on the electron dot structures pioneered by G. N. Lewis. While the theory retains the requirement for fulfilling the octet rule , it dispenses with the need to force electrons into coincident pairs .
Some sources indicate the Lewis base with a pair of dots (the explicit electrons being donated), which allows consistent representation of the transition from the base itself to the complex with the acid: Me 3 B + :NH 3 → Me 3 B:NH 3. A center dot may also be used to represent a Lewis adduct, such as Me 3 B·NH 3.
Lewis proposed that an atom forms enough covalent bonds to form a full (or closed) outer electron shell. In the diagram of methane shown here, the carbon atom has a valence of four and is, therefore, surrounded by eight electrons (the octet rule), four from the carbon itself and four from the hydrogens bonded to it. Each hydrogen has a valence ...
A molecular orbital diagram, or MO diagram, is a qualitative descriptive tool explaining chemical bonding in molecules in terms of molecular orbital theory in general and the linear combination of atomic orbitals (LCAO) method in particular.
The trihalides adopt a planar trigonal structure. These compounds are Lewis acids in that they readily form adducts with electron-pair donors, which are called Lewis bases. For example, fluoride (F −) and boron trifluoride (BF 3) combined to give the tetrafluoroborate anion, BF 4 −. Boron trifluoride is used in the petrochemical industry as ...