Boron shows anomalous behaviour in group 13 because of its small size and absence of d orbital.
Anomalous properties of boron
Boron is observed to have properties that are in contrast to the other elements of the boron family due to the following reasons:
- It has a very small size
- It has a very high ionisation enthalpy
- It has high electronegativity owing to its small size
- The absence of d-orbital in the valence shell
Some of these odd characteristics are discussed below.
- Except for boron, the compounds of the elements of the boron family-like tetrahedral [M(OH)4]– and octahedral [M(H2O)6]3+ (where M denotes the member of the boron family) exists in an aqueous medium.
- The maximum covalence of boron is 4 due to the absence of d orbitals.
- Boron is a metalloid, while the others are post-transition metals.
- The oxides and hydroxides of boron are acidic, while the oxides and hydroxides of the other elements in the family are amphoteric.