topic 7 Flashcards
[Cu(h2o)6]2+ shape
2 longer axial
4 shorter equatorial
octahedral shape
jahn teller distortion
when degenerate orbitals are occupied by a different number of e-
the molecule distorts to a lower energy form
examples of degenerate orbitals
eg and eg
t2g and t2g
when both eg orbitals have 1 e- inside they areee
not affected by the jahn teller effect
there’s only 1 way they can be filled while respecting the aufbau, pauling and hunds rule
d config that doesn’t lead to jahn teller effect
d8
6 e- in t2g
2 e- in the eg
d9 and e- config
6e- in the t2g
3e- in the eg
the eg can be arranged 2 different ways: 1 and 2 or 1 and 2
what is diff about d8 and d9
d9 is affected by the jahn teller effect
makes the 2 axial bonds longer
there is jahn teller distortion in d9 but not in d8
what happens to the orbitals in the jahn teller distortion complexes
the ones with Z will get lower in energy than the other ones:
t2g: dxz and dyz will be lower than dxy
eg: dz2 will be lower than d x2-y2
octahedral complexes normally have whag configuration
d12
square planar complexes usually have what configuration
d8
difference between octahedral shape and square planar shape
octahedral loses its 2 axial ligands to form a square planar
octahedral, xxx, square planar
tetragonal
distortion
(long axial bonds) in octahedral
high spin d8 usually what what configuration
octahedral
tetrahedral
low spin d8 usually have what shape
square planar
what orbital is empty in the low spin eg d8
the d x2-y2
bc dz2 goes down in energy and gets occupied by both the e-
what shape occurs in all pt complexes
square planar
energy gained when square planar forms is larger than the the pairing energy and the loss of the 2 ligands
down the group for elements with d8 there sre
more square planar orientations
is ligand exchange 2 step process
in first row DBE yes!!
it’s dissociative
the ligand being replaced is lost before the new incoming ligand coorinaged
what is the slowest step in ligand exchange
losing the ligand
fastest step in ligand exchange
coordination of the new ligand
what is a 5 coordination transition state
the ‘intermediate’ of ligand exchange
either
trigonal bipyramidal
square pyramidal
describe square pyramidal
square planar with 1 ligand on top
or octahedral with 1 ligand missing at the bottom
what else affects ligand exchange
- charge and size of metal ion
- nature of the leaving group (bond strength)
- crystal field effects (ground to excited states)
(-) values = fast rea
(+) values = slow rea
exchange equation
[M]-L. reversible [M] + L
