The coordination number for the Al3+ ion is typically between four and six. Use the anion coordination number to determine the Al3 + coordination number in the following compounds: (b) Al2O3 where the oxygen ions are six coordinate.

Key Concepts

Coordination Number

The coordination number refers to the number of ligand atoms that are bonded to a central metal ion in a complex. It is a crucial concept in coordination chemistry, as it influences the geometry and stability of the complex. For example, a coordination number of six typically leads to an octahedral geometry, while four can lead to either tetrahedral or square planar arrangements.

Aluminum Ion (Al3+)

The aluminum ion, Al3+, is a common cation in coordination compounds, characterized by its +3 charge. This high charge density allows it to attract and coordinate with multiple anions or ligands. Understanding the properties of Al3+ is essential for predicting its behavior in various compounds, including its coordination number and the resulting structure.

Anion Coordination

Anion coordination refers to the arrangement and bonding of anions around a central cation in a compound. The coordination number of the anions can influence the overall structure and stability of the compound. In the case of Al2O3, where oxygen ions are six-coordinate, this indicates that each aluminum ion is surrounded by six oxygen ions, which helps determine the coordination number of the aluminum ions.