Examples of Monodentate Ligands

A monodentate ligand has one point at which it can attach to the central atom. Many simple anions, or more accurately Lewis bases, can act as monodentate ligands, including
      chloride ion (Cl-),
      hydroxide ion (OH-),
      water (H2O), and
      ammonia (NH3).

When aqueous copper ions (Cu2+(aq)) are reacted with an excess of aqueous ammonia, a beautiful deep vivid blue-colored complex forms:

tetraamminediaquacopper(II) ion, which can also be written as
[Cu(NH3)4(H2O)2]2+
The four ammonia
molecules occupy equatorial positions, and the water molecules occupy axial positions,
yielding a complex in which the central atom is octahedrally coordinated.

To help you visualize what is going on, here is an interactive model of the same complex ion. The ammonia and water ligands are shown as heavy sticks.

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