Reaction between two different halogens
Types: XX’, XX’3, XX’5 and XX’7
X – Halogen of larger size, more electropositive
X’- Halogen of smaller size
\(\frac{Radius\text{ }of\text{ }X}{Radius\text{ }of\text{ }X’}\propto No:\text{ }of\text{ }atoms\text{ }per\text{ }molecule\)
Preparation:
- Direct combination.
- Product depends on the concentrations of the reactants.
Cl₂ + F₂ → 2ClF
Cl₂ + 3F₂ → 2ClF₃
Properties:
- Covalent molecules
- Diamagnetic
- Volatile solids/liquids {except ClF which is a gas}
- More reactive than halogens {except Fluorine} because X – X’ bond is weaker than X – X bond
- All are polar due to difference in their electronegativity.
- Some compounds partially ionize in solution. For example:
- 2ICl → I⁺ + ICl²⁻
Structure:
- XX₃ – bent T shape
- XX₅ – Square pyramidal
- IF₇ – Pentagonal bipyramidal
Uses:
- Some interhalogens, such as BrF3, IF5, and ICl, are good halogenating
Ex: U + 3ClF₃ → UF₆ + 3ClF - Iodine monochloride helps to measure the saturation of fats and oils, and as a catalyst for some reactions.
- A number of interhalogens, including IF7, are used to form polyhalides.