1. Both oxygen and sulfur form gaseous, triplet ground-state, diatomic molecules. Simple molecular orbital theory predicts a bond order of 2 for both molecules. Unlike molecular oxygen, molecular sulfur is unstable with respect to the formation of other allotropic forms, all of which consist of polymeric or cyclic molecules in which each sulfur atom is bonded to two other sulfur atoms by single bonds. The most corlmon of the sulfur all otropes consists of S8, a cyclic molecule with the structure shown below.
Explain why diatomic sulfur is unstable relative to formation of olisomeric/oolvmeric species involving only single bonds, whereas oxygen is stable. Response must includes rationales for the relative stengths of homonuclear oxygen and sulfur σ and ∏ bonds.
|
BDE. kJ mol-' |
| x |
x-x |
X:X |
| o |
t45 |
495 |
| S |
270 |
425 |
