Coordinate Bonds
What are coordinate bonds?
- In simple covalent bonds the two atoms involved share electrons
- Some molecules have a lone pair of electrons that can be donated to form a bond with an electron-deficient atom
- An electron-deficient atom is an atom that has an unfilled outer orbital
- So both electrons are from the same atom
- This type of bonding is called dative covalent bond or coordinate bond
- An example of a dative bond is in an ammonium ion
- The hydrogen ion, H+ is electron-deficient and has space for two electrons in its shell
- The nitrogen atom in ammonia has a lone pair of electrons which it can donate to the hydrogen ion to form a coordinate bond
Dative covalent bonding ammonium ion
Ammonia (NH3) can donate a lone pair to an electron-deficient proton (H+) to form a charged ammonium ion (NH4+)
- More examples of coordinate bonding can be found in the section on Lewis Structures
Examiner Tip
Coordinate bonds are also referred to as coordination bonds or dative covalent bonds.
