6a

Question 1

T terms are split by what to produce what

Answer 1

theyre split by spin orbit coupling to produce levels whose energy differences are in the order of kT

Question 2

T terms are temp dependent yes or no

Answer 2

yesss

temp has an effect on the population of the levels and we expect the magnetic moment to be temperature dependent

Question 3

if the T term is temp dependent,, what else is temp dependent

Answer 3

if the T term is temp dependent that also means that the magnetic moment is affected by temperature

temp will also affect the polulation of the energy levels that the T term splits into

Question 4

kotani plots,, axis

Answer 4

ueff (magnetic moment)
kT/h
where h is the spin orbital coupling constant

Question 5

whats h

Answer 5

h is the wavelength looking thing,, this is the spin orbit coupling constant

Question 6

calculations have happily done before us by other ppl to do what

Answer 6

to determine the effect of spin orbit coupling on the orbitally degenerate ground terms

Question 7

for each term,, how many plots can be drawn

Answer 7

for each term,, two plots can be drawn

Question 8

if two plots can be drawn for each term,, ehat 2 plots can be drawn

Answer 8

u have the positive h plot for d1-d4
u have the negative h plot for d5-d9

Question 9

whats h again

Answer 9

spin orbit coupling constant

Question 10

d1-d4,, h ,, the spin orbit coupling constant will be

Answer 10

it will be positive

Question 11

for d5-d9 , h, the spin orbit coupling constant will be what

Answer 11

it will be negative

Question 12

when we have a kotani graph or any graph,, what can we deduce from the graph labels

Answer 12

u can decude their spin multiplicity
bc this is the thing top left
u do 2s+1 = top left number

then u can see if transitions will be spin allowed // forbidden and therefore predict their intensities

Question 13

u = if we have spin and orbital contribution

Answer 13

root 4s(s+1) + L(L+1)

Question 14

do things acc follow kotani plots tho

Answer 14

nopeee
things dont acc follow kotani plots sadly

Question 15

kotsani plot axis

Answer 15

magnetic moment against temp

Question 16

why dont things fit with kotani plots

Answer 16

bc of covalent bonding

Question 17

why does covalent bonding mean that kotani plots dont represent stuff ralistically

Answer 17

bc in covalent bonding, the unpaired e- dont stick by the metal
the e- move from the metal onto the ligand

if the unpaired e- move from the metal to the ligand they cannot contribute to the orbital angular momentum around the metal

Question 18

wait what are all the reasons that things dont fit kotani plots

Answer 18

• covalency
• jahn teller distortions

Question 19

why do jahn teller distortions prevent things from fitting kotani graphs

Answer 19

the e- configs are subject to jahn teller distortions

the distortion splits the ground state into A or E terms meaning that the complex will now be temp independent (the e- cannot be places somewhwre with 3 diff arrangements)

Question 20

when does jahn teller occur

Answer 20

when theres asymmetric filling of degenerate orbitals

the complex removes degeneracy

Question 21

the splitting of jahn teller can be what

Answer 21

it can be big or small

either way it can be detected by magnetic measurements

Question 22

the size of a jahn teller distortion can be measured how

Answer 22

it can be measured // estimated by fitting the experimental plot of magnetic moment against T with various ratios of delta/h (h being the spin orbit coupling constant)

delta = the splitting between the singlet and doublet energy levels

Question 23

A value of Oh corresponds to what

Answer 23

it corresponds to Oh symmetry

Question 24

the best fit of the graph does what

Answer 24

gives delta value

aka the sep between singlet and doublet values

Question 25

a study of magnetic properties over a temp range allows what

Answer 25

allows us to see what is a T an A or an E ground state can also help us deduce stereochemistry

Question 26

Oh transition metal complex:cML6 ^+3 - 3 strong d-d transitions (17400, 24600, 37800 all bands have an E mec of 10M-1 mag moment, u = 3.55BM ,, this doesnt vary with temp kinetically inert can be reduced to 2+ one d-d transition in the uv spec mag momment of 4.67 BM whihc is also temo independent suggest what M , L are and explain all obvs,, find delta o for the original complex

Answer 26

its ML6: so think Oh geom 3, d-d transitions means it can be a d2, d3, d7, d8 metal (larporte forbidden dd transition) if the BM is 3.55 thats close to 3.87 which is n=3,, root n (n+2) spin only magnetic moment is larger than magnetic moment so its d1-d4 kinetically inert so maybe d3 reduced to +2 from 3+ means were adding an e- if its temp independent that means its an A or E term M = Cl bc it has to be d3 and 3+ means it has 6d electrons in total a high spin complex means the ligand is a weak field ligand meaning we need a neutral weak field ligand like NH3!! for d3 the delta value is equal to the first transition. so delta = 17400!!

Question 27

if we have 1 weak but 1 strong transition,, what d electron count could it be

Answer 27

LSd6

Question 28

if u have 1 band as a transition,, what d electron count can it be

Answer 28

d1, d4, d6, d9

Question 29

if we have multiple sharp and weak peaks what d electron count can it be

Answer 29

it can be a d5 complex

Question 30

a MLn ^+2 complex has a magnetic moment of 4.1BM wihich varied with temperature 3 d-d trnaitions of moderate intensity,, 8100, 1600, 19400,, all bands have an E of 5 complex can be oxidisedt o +3,, whuch has a magnetic moment of 0 theres 3 bands in the uvvis spec ,, 2 bands are strong 16500 and 24700 and one was weak at 8000 find M and L and a valye for n

Question 31

old spin only magnetic moment that we use to get BM

Answer 31

root n (n+2) where n is the number of unpaired e;lectrons

Question 32

if they give u magnetic moment what do u need to do when trying to predict the complex

Answer 32

do the root n (n+2) equation and try find what n is this gives u the number of unpaired electrons u have

Question 33

if we have more unpaired e- once chem occurs to a complex when trying to guess the complex,, what does this mean

Answer 33

if means we wither gained or losr an e-,, and this e- was either gained and went o an emptry orbital or it was removed and left its pair by itself

Question 34

if a complex is reduced and the number of unpaired e- what can we say

Answer 34

we can say that the complec was low spin and that the e- that was gained went into a higher energy orbital.

Question 35

what else causes variation in magnetic moment

Answer 35

the spin aka if smt is high spin or low spin

Question 36

whats a spin crossover compound

Answer 36

one where the spin changes as temp changes

Question 37

what d configs can exist in one of two spin states depending on if Pe is bigger than delta or if delta is bigger than PE

Answer 37

d4, d5, d6, d7

Question 38

what should we think of when we think of spin corssover complexes

Answer 38

the energy difference between the diff spin states is sosmall that a change in temp can cuase their spin to change aka the transition between low spin to high spin is small

Question 39

high spin normally occurs when temp is what

Answer 39

when temp is large,, complexes are normally high spin

Question 40

low spin complexes are normally low spin in what temp

Answer 40

low spin in low temp

Question 41

how many types of spin crossover complexes are there

Answer 41

theres 2 types of spin crossover complexes

Question 42

what are the two types of spin cross over species

Answer 42

- a simple equilibrium more cmplex transitions

Question 43

whats the simple equilibrium spin crossover complex thing

Answer 43

its.a spectrum,, its not just going from ls to hs. spin corssover occurs when delta o is around 16500cm-1 at low temp magnetic moment will be low spin as temp increases, the magnetic moment increases as more high spin species are formed the limiting value is 4.47BM where theres a 50:50 ratio of hs and ls

Question 44

in the simple equilibrium spin corss over complex thing,, as temp increases,, what happens to the ratio of ls and hs

Answer 44

u start at ls but u start to increase and they start forming more hs,, esp if deltao is 16500

Question 45

==why is the limiting valur of ls and hs in spin crossover around 4.47

Answer 45

bc this is the 'average' of low and high spin

Question 46

whats the more complex transition for spin crossover species about

Answer 46

its about how in mostly solids,, interactionsbetween mowlcules can trigger a phase transition. its about the bulk changing from low to high spin when heated or from high to low spin when cooled.

Question 47

in the more complex transition spin corss coupling thing,, how can we remmeber its the more complex transition one

Answer 47

bc the basic one is just chnaging spin states when u change temp,, the more complex phase one is all about there being a phase transition and then the bulk changng spin states all together

Question 48

in the complex transition thing,, when will there be more unpaired e-

Answer 48

there will be more unpaired e- when ur at high spin

Question 49

in the complex transition spin corss coupling thing,, when are we more likely to have more paired e-

Answer 49

when we have low spin

Question 50

in the complex transition cross coupling thing,, is the change in magnetic moment large

Answer 50

yes!! bc its the bulk changing,, and the bulk is either changing to be all low or high spin,, so lots of changes in the e- and if theyre paired up or not so yes! the change in magnetic moment will be large