Which of the following has square pyramidal structure?
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → BrF5
The shapes of interhalogen compounds follow from VSEPR theory: count the bond pairs and lone pairs on the central atom, which has 7 valence electrons.
In \( \ce{BrF5} \), Br uses 5 electrons for five Br–F bonds and keeps 2 as one lone pair. Six electron pairs take an octahedral arrangement; with one position taken by the lone pair, the five F atoms form a square pyramid (sp3d2).
Why the other options are incorrect
Option (1) IBr — Incorrect. A diatomic molecule, which is necessarily linear.
Option (2) IF7 — Incorrect. 7 bond pairs, no lone pair: pentagonal bipyramidal.
Option (3) ClF3 — Incorrect. 3 bond pairs and 2 lone pairs (trigonal bipyramidal arrangement): bent T-shaped.
Note: This question is from the pre-rationalised NCERT book (2022-23). The topic is not there in the latest NCERT book (2026-27), and it is also out of the CUET 2026 syllabus.
NCERT (Pre-rationalised edition, 2022-23):
Interhalogen Compounds – …
