Intermediate Topic 132 of 1102 Bonding & Molecular Structure
Coordinate Bond
A covalent bond where both shared electrons come from the same atom, as in NH4+.
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In-depth explanation of Coordinate Bond
A coordinate bond, also called a dative bond, is a covalent bond in which both shared electrons come from the same atom. The donor atom supplies a lone pair, and the acceptor supplies an empty orbital to receive it. Once formed, the coordinate bond is indistinguishable from an ordinary covalent bond in length and strength, although it is sometimes drawn with an arrow. Coordinate bonds are essential in forming complex ions, Lewis acid-base adducts and protonated species. Metal complexes form when ligands donate lone pairs to metal ions.
Going deeper: Coordinate Bond
Key ideas: Identify it by electron counting: the donor has a lone pair, and the acceptor has an empty orbital, as H+ has an empty 1s. Formal charge changes: N in NH4+ has +1. Typical examples are NH4+, H3O+, BF3-NH3 and metal-ligand bonds. Once formed it behaves like any single covalent bond.
Common mistakes and connections: Learners think a coordinate bond is weaker or different in length than a regular bond, but all four N-H bonds in NH4+ are identical. Another error is giving the acceptor a lone pair or forgetting formal charge on the donor atom. Connects to Lewis acids and bases, coordination compounds, ligands and proton transfer.
Visualization of Coordinate Bond
Ammonia donates its lone pair to H+ to form NH4+. Once formed, all four N-H bonds are identical, so the dative origin of one cannot be told apart. The interactive lesson shows this as a live animation or chart.
Worked example and use case
NH3 combines with H+ to form NH4+, in which all four N-H bonds are identical.
Frequently asked questions about Coordinate Bond
What is Coordinate Bond?
A covalent bond where both shared electrons come from the same atom, as in NH4+.
Is Coordinate Bond a beginner, intermediate or advanced topic?
Coordinate Bond is a intermediate topic in Bonding & Molecular Structure. It builds on the vocabulary of beginner topics in this area.
What should I learn before Coordinate Bond?
Study these earlier topics in Bonding & Molecular Structure first: Expanded Octet, Incomplete Octet, Odd-Electron Molecules.
What comes after Coordinate Bond?
The next topics in Bonding & Molecular Structure are Bond Length and Bond Energy.
Can I practise Coordinate Bond with quizzes?
Yes. The interactive lesson includes a self-check question on Coordinate Bond, and the Bonding & Molecular Structure quiz draws on every topic in this area.
Where Coordinate Bond fits in Bonding & Molecular Structure
Coordinate Bond is topic 17 of 104 in Bonding & Molecular Structure.