Question

The bond length and bond angle of S$_8$ ring in rhombic sulphur are respectively:

• A. 104 pm, 107°
• B. 204 pm, 107°
• C. 304 pm, 107°
• D. 194 pm, 120°

Hint:

S$_8$ exists as a puckered ring; S–S bond length is ~204 pm due to single bond character.

Answer 1

The Correct Option is B

Step 1: Picture the actual shape of $S_8$.
Rhombic sulphur exists as a puckered, crown shaped eight membered ring, where every sulphur atom is joined to its two neighbours by a single covalent $S-S$ bond, not a flat ring.

Step 2: Compare with a reference bond, rather than quoting the length directly.
Sulphur has a larger atomic radius than oxygen, and a single $S-S$ bond is noticeably longer than a single $O-O$ bond because of this size difference. Standard $S-S$ single bonds across sulphur allotropes and compounds are consistently measured near $204$ pm, so this value fits the general pattern for sulphur to sulphur single bonds rather than being a one off number.

Step 3: Reason out the bond angle from the geometry.
Each sulphur atom in the ring is roughly $sp^3$ hybridized, which would give a tetrahedral angle of about $109.5^{\circ}$ if there were no distortion. The puckering of the crown shape squeezes this down slightly, landing close to $107^{\circ}$.

Step 4: Check why the ring puckers at all.
A completely flat 8 membered ring would force a lot of angle strain and unfavorable eclipsing between neighbouring atoms. Puckering into the crown form relieves that strain, and this relief is what fixes the angle near $107^{\circ}$ rather than the ideal tetrahedral value.

Step 5: Match against the options.
Only the pair $204$ pm and $107^{\circ}$ matches both the expected $S-S$ single bond length and the puckered ring angle together.

Step 6: Final answer.
\[ \boxed{204\ \text{pm},\ 107^{\circ}} \]