18 Electron Rule And Structure Flashcards
(6 cards)
1
Q
Most stable organometallic complex
A
When total electron count at MC = 18e-
2
Q
Eg and bonding in octahedral complexes
A
Dx2-y2 and dz2 point directly at ligands so form anti bonding interactions with ligands
3
Q
T2g and bonding in octahedral complexes
A
Dxz, dyz and dxy point between ligands = no interaction = NBMO
4
Q
Spectrochemical series
A
Increasing Δo: weak σ-donors/π-acceptors eg halides < simple σ-donors eg water/ammonia < strong σ-donors/π-acceptors eg PPh3, CO
5
Q
When does the 18e- rule apply
A
When bonding favours 6e- in t2g AO:
Strong field ligands = large Δo
Ligands that promote occupation of t2g = π-acceptors
Relatively small ligands = sterics
6
Q
Exceptions to 18e- rule
A
Large ligands = not enough room
