Q.Which form of sulphur shows paramagnetic behaviour ?

Sulphur exists in several allotropic forms, the most common being rhombic ($\alpha$) sulphur and monoclinic ($\beta$) sulphur, both built from puckered, crown-shaped $S_8$ ring molecules held together only by weak van der Waals forces between rings; rhombic sulphur is stable below about 369 K and converts to monoclinic sulphur above this transition temperature. Molten sulphur poured suddenly into cold water quenches into an amorphous, elastic, chain-like solid called plastic sulphur. At very high temperature, sulphur vapour contains diatomic $S_2$ molecules whose electronic structure parallels that of $O_2$, with two unpaired electrons occupying antibonding $\pi^*$ orbitals; this vapour-phase $S_2$ is the paramagnetic form of sulphur, unlike the ordinary diamagnetic ring allotropes found at room temperature. Elemental sulphur occurs both …