Question
Which one of the following species does not exist under normal conditions?
-
Be2+
-
Be2
-
B2
-
Li2
Solution
B.
Be2
Molecules with zero bond order do not exist.
a) Be2+ (4 + 4 -1 = 7) = σ1s2 σ*1s2, σ2s2, σ2s1
BO = 4 - 3 / 2 = 0.5
b) Be2 (4 + 4 = 8 ) = σ1s2, σ*1s2, σ2s2, σ*2s2
BO = 4 - 4 / 2 = 0
c) B2 = (5 + 5) = 10
= σ1s2 , σ*1s2, 2σs2, σ*2s2, π2px1 = π2py1
BO = 6 - 4 /2 = 1
BO = 4 - 4 / 2 = 0
c) B2 = (5 + 5) = 10
= σ1s2 , σ*1s2, 2σs2, σ*2s2, π2px1 = π2py1
BO = 6 - 4 /2 = 1
d) Li2 (3 + 3) = 6
= σ1s2 , σ*1s2,σ2s2
BO = 4 - 2 / 2 = 1
Thus, bond order of Be2 does not exist under normal conditions.
= σ1s2 , σ*1s2,σ2s2
BO = 4 - 2 / 2 = 1
Thus, bond order of Be2 does not exist under normal conditions.
