Donorakseptorisidokset

Donorakseptorisidokset, also known as dative covalent bonds or coordinate covalent bonds, are a type of covalent bond where both electrons in the shared pair originate from only one of the atoms. In a typical covalent bond, each atom contributes one electron to form the shared pair. However, in a donor-acceptor bond, one atom, the donor, provides a lone pair of electrons, and the other atom, the acceptor, has an empty orbital available to accept this pair.

This type of bond is commonly found in coordination complexes. For example, in the complex ion tetraamminecopper(II), [Cu(NH3)4]2+, the copper(II) ion (Cu2+) acts as the electron acceptor, possessing empty d-orbitals. The ammonia molecules (NH3) act as electron donors, with the nitrogen atom in each ammonia molecule having a lone pair of electrons. These lone pairs are donated to the copper ion, forming four donor-acceptor bonds.

Donor-acceptor bonds are crucial in understanding the structure and reactivity of many chemical species, including Lewis acids and bases. A Lewis acid is a species that can accept an electron pair, thus acting as an acceptor. A Lewis base is a species that can donate an electron pair, acting as a donor. The formation of a donor-acceptor bond is essentially the reaction between a Lewis acid and a Lewis base. While the origin of the electrons differs, once formed, a donor-acceptor bond is indistinguishable from a typical covalent bond in terms of its properties like bond length and strength.