In: Chemistry
Comment on the structure of O2, its spin state, and magnetic properties. What other electronic states of dioxygen are known. How are they different from the ground state.Apply MO theory if applicable.
Solution:
The molecular orbital diagram of O2 contains 10 electrons in bonding and 6 electrons in antibonding molecular orbitals. Thus,
Bond order = (10 - 6)/2 = 2
Thus, molecule is very stable. The presence of two unpaired electrons makes it paramagnetic in character.
Dioxygen has two different electronic states (singlet and triplet). Singlet state is the lowest excited state of the dioxygen molecule and has only one possible arrangement of electron spins with a total spin number (S) of 0. The triplet state has three possible arrangements of electron spins with a total spin number (S) of 1.
Singlet ( 2S+1) = 1 [ Because S =0]
Triplet (2S+1) = 3 [Because S = 1]