Question

Which one of the following statements is not true in respect of properties of interhalogen compounds?

• A. They are all covalent compounds
• B. They are volatile solids or liquids except ClF
• C. IF\textsubscript{5} has square pyramidal structure
• D. They are all paramagnetic in nature
• E. BrF\textsubscript{3} is used in the preparation of UF\textsubscript{6} in the enrichment of \textsuperscript{235}U

Hint:

A simple way to remember: Most stable, neutral p-block molecules where atoms have even total valence electrons (like interhalogens) are diamagnetic. Paramagnetism is rare and usually found in odd-electron species like NO or NO\textsubscript{2}.

Answer 1

The Correct Option is D

Concept: Interhalogen compounds are molecules formed by the combination of two different halogen atoms (e.g., AB, AB\textsubscript{3}, AB\textsubscript{5}, AB\textsubscript{7}).
• Bonding: Halogens have high electronegativity differences, leading to the formation of covalent bonds between different halogen species.
• Magnetic Property: In these compounds, all valence electrons of the halogen atoms are paired up during bond formation. Because there are no unpaired electrons, interhalogen compounds are diamagnetic.
• Structures: The geometries are determined by VSEPR theory (e.g., IF\textsubscript{5} has 5 bond pairs and 1 lone pair, resulting in a square pyramidal shape).

Step 1: Evaluate the magnetic nature of interhalogens. Paramagnetism requires the presence of one or more unpaired electrons. In interhalogen compounds like ClF, BrF\textsubscript{3}, or IF\textsubscript{5}, the atoms share electrons to complete their octets (or expanded octets). This pairing of electrons makes the entire group of compounds diamagnetic. Thus, statement (D) is false.

Step 2: Verify the validity of other statements. Statements (A), (B), (C), and (E) are factual properties: - They are covalent due to halogen nature. - IF\textsubscript{5} is indeed square pyramidal ($sp^3d^2$ hybridization). - BrF\textsubscript{3} is a powerful fluorinating agent used to produce UF\textsubscript{6} from Uranium for nuclear fuel processing.