Q118 · CSIR-NET Chemistry, June 2011
Paper: CSIR-NET June 2011 · Subject: Physical Chemistry · Chapter: Group Theory · Topic: Symmetry Elements Point Groups · Marks: 2 · Difficulty: Medium
Identify the point group symmetry of the following molecule (all C-C bond lengths are equal) 
(a)$\mathrm{C}_{2 \mathrm{v}}$
(b)$\mathrm{S}_{4}$
(c)$\mathrm{D}_{2 \mathrm{d}}$
(d)$\mathrm{D}_{4 \mathrm{d}}$
Answer
Answer: C ✓ checked by 4AB · confidence medium
Explanation
Puckered 1,2,3,4-tetrasubstituted cyclobutane with the X groups alternating up and down. It has S₄ plus two C₂ axes and two dihedral mirror planes, so D₂d (chapter key c).
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