Potassium permanganate forms dark purple (almost black) crystals. These crystals are isostructural with the crystals of which of the following compounds?
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → \( \ce{KClO4} \)
Isostructural crystals have the same crystal structure. Potassium permanganate, KMnO4, and potassium perchlorate, KClO4, have the same type of formula: a K+ ion with a singly charged anion carrying four oxygen atoms, and their crystals have the same structure.
NCERT (2026-27 edition):
4.4.1 Oxides and Oxoanions of Metals – “Potassium permanganate forms dark purple (almost black) crystals which are isostructural with those of KClO4.”