Question

Why are the participating atoms of a coordinate bond called the donor and the acceptor?

Short answer

Answer: The participating atoms in a coordinate bond are called the donor and the acceptor because the bond formation involves the transfer or sharing of electrons from one atom to another. The donor atom provides both electrons for the bond formation, while the acceptor atom receives the pair of electrons, resulting in the establishment of a stable bond between the two atoms.

Step-by-step solution

Define a coordinate bond

A coordinate bond is a type of covalent bond in which both electrons that form the bond come from the same atom. In other words, one atom donates a pair of electrons to form the bond, while the other atom accepts these electrons.

Identify the donor atom

In a coordinate bond, the donor atom is the one that provides both electrons for the bond formation. This atom has a lone pair of electrons that can be shared, which usually results from having an extra electron or an unshared electron pair.

Identify the acceptor atom

The acceptor atom is the one that accepts the pair of electrons shared by the donor atom in coordinate bonding. This atom usually has an empty orbital or lacks a complete octet (eight electrons in its outer shell), so it requires additional electrons to achieve stability.

Explain the terms "donor" and "acceptor"

The terms "donor" and "acceptor" are used to describe the participating atoms in a coordinate bond because the bond formation essentially involves the transfer or sharing of electrons from one atom to another. The donor atom provides the electrons (hence, 'donates'), while the acceptor atom receives or accepts the electrons, resulting in the establishment of a stable bond between the two atoms.

Key concepts

Donor Atom

In the context of a coordinate bond, a donor atom plays a pivotal role by providing both electrons needed to form the bond. This atom typically has a lone pair of electrons, which are not involved in other bonds. These lone pairs represent an extra electron pair that the atom can use to engage in bonding.

The donor atom is called so because it 'donates' this pair of electrons to an acceptor atom, creating a covalent link that stabilizes the involved molecules. Donor atoms are often found in elements such as nitrogen and oxygen. These atoms contain lone electron pairs making them candidates for forming coordinate bonds.

When studying donor atoms, it's essential to consider their electronic configuration because lone pair availability directly influences the atom's ability to partake in coordinate bonding.

• Lone pair presence is crucial.
• Typical examples include atoms such as nitrogen and oxygen.
• They must be able to form stable bonds through sharing their lone pairs extensively.

Acceptor Atom

On the opposite side of a coordinate bond is the acceptor atom. This atom is distinct in that it does not contribute electrons to the bond but instead accepts the electron pair from the donor atom. Typically, an acceptor atom has an empty orbital or an incomplete valence shell—usually a lack of a full octet which makes it inherently unstable.

Accepting electrons helps the atom achieve a more stable electronic configuration by filling its valence shell. The atom's need for additional electrons drives it to bond with the donor atom, ensuring the structural integrity and stability of the resulting compound.

Acceptor atoms can often be transition metals or other elements with unfilled orbitals that accommodate the lone pair transferred by the donor.

• Acceptor atoms often have partially filled orbitals or incomplete octets.
• Achieving electron stability is a key motivation for accepting atoms to engage in coordinate bonding.
• They facilitate stabilization by receiving electron pairs.

Electron Pair Sharing

Electron pair sharing is the essence of a coordinate bond, distinguishing it from typical covalent bonds. In a typical covalent bond, each atom contributes one electron to form the bond. However, in a coordinate bond, the donor atom provides both electrons for the bond.

This arrangement results in a mutual sharing that allows both atoms involved to reach a stable electronic structure. The sharing supports the concept of valence and satisfies the electron needs of the involved atoms by spreading the electron density between them.

The atoms thus share the electron pair unequally, stressing on coordination rather than completion. This leads to a special type of bonding that is both unique and widely applicable in various chemical reactions and structures.

• Distinct because only one atom provides the electron pair, unlike in traditional covalent bonds.
• Stabilizes both atoms by creating a shared electron environment.
• Key in forming compounds with unique properties and bonds.