9a

Question 1

whats molecular antiferromagnetism

Answer 1

its where u have 2 TM with unpaired e-,, and theyre bonded together by a bridging ligand

theres a magnetic interaction between them ,, these magnetic properties arent additive

Question 2

the e- distribution of the ligand // bridging ligand is affected by what

Answer 2

its affected by the unpaired e- distribution of the metal its bonded to

Question 3

when we think of molecular magnetism,, what should we think of

Answer 3

think M - X - M
with bond angles which affect it a lot!!

Question 4

if we are given the dimer thing of M - X - M,, what do we need to do

Answer 4

figure out the d e- count and see where the unpaired e- is,, if its in the t2g or the eg.

then draw the orbital u just figured out and draw the p orbital for the ligand,, make sure u draw it so it matches

then fill the e- in ,, it can be random at first but then u need to acc think,, remember to fill in all the p orbital e- bc this is very important if u want the right answer

then look at the e- in the e,tal and see if theyre aligned or not. aligned = ferro ,, not aligned = antiferro

Question 5

eg orbital unpaired e- looks like

Answer 5

a Jesus cross

Question 6

t2g orbital unpaired e- look like what

Answer 6

a pirate cross

Question 7

if we have 2 t2g metal orbitals,, what p orbital do we use

Answer 7

we use the standing up one rather than the flat // chicken leg one

Question 8

if we have orbitals that are orthogonal ,, aka ones that dont line up completely // perfectly,, what are they called and how do we fill them with e-

Answer 8

theyre called orthogonal and we say that the e- in these want to be aligned,, aka if thigs dont match up directly we put the e- facing the same way

think of hunds rule and how u put them in with the same spin direction

Question 9

when filling our diagrams with e-,, what. do we need to make sure we do

Answer 9

we need to make sure we fill the p orbital completely before moving ontp the other metal!!! to make sure we have the correct metal e- arrangement

Question 10

what do we need to make sure we do when our angle is 90* and we have a px and py cross thing for our ligand and a eg for the metals

Answer 10

we fill the first metal with an e- in any direction.. then we put the e- in one of the p petals,, then we put the other e- in the other petal,, then we still have the downward p orbital and for this one we need to make sure that the top p petal is aligned with the second e- we added to it,, so make sure the 2ne and the 3rd p e- are aligned aka in the same alignment. then we fill in the 4th and the other metal one!!

we then look at the metals and see if the e- are aligned or not. aka ferro or antiferro

Question 11

whats the whole draweing the d and the p orbital and finding the magnetism thing called

Answer 11

its called the super exchange pathways and its used to predict magnetism

Question 12

how do we predict // find how strong these interactions are,, aka the interactions with magnetism

Answer 12

we quantify J in bimetallic complexes

Question 13

what is J

Answer 13

J is the enrrgy change between the triplet and singlet state.

triplet being if the s=1 and singlet being if the s = 0

Question 14

if J aka change in energy is positive,, what does that mean

Answer 14

it means u have ferromagnetism

aka the e- in the metals are aligned
and that them being aligned is the lower energy state aka the one we want to be in most the time

Question 15

if J aka chnage in energy between singlet and triplet is negative,, what does this mean

Answer 15

it means that the metals // the thing is antiferro magnetism

aka the e- are no aligned

this means that the spins being in opposite directions is acc the lowest energy state

Question 16

when we know what the spin is,, how do we find J

Answer 16

we know spin so therefore we know what equation to use,, bc the equations show u whcih one to use for each spin bit

we then fit ‘X’ ,, aka suscpetibility against T,, the line of best gives u J

Question 17

when we plot X against T what do we need to do

Answer 17

we need to chnage J

bc X = J/KT

X includes J

so u vary J until u get the best fit

Question 18

the more positive J is the more what

Answer 18

the stronger the ferro interaction

Question 19

the more negative the J value the more what,, the more negative the what

Answer 19

the more negative the value., th stronger the antiferro interaction

Question 20

if we have an acute angle what should we think

Answer 20

we should think that its probs ferro magnetic coupling

Question 21

the more obtuse the angle the more what

Answer 21

the more obtuse the angle,, its more likely to be antiferromagnetism

Question 22

if we have a metal oxide,, as we increase the covalency what happens

Answer 22

as u increase covalency in bonds,, u increase the Tneel (k) aka the neel temperature

aka as u go go from early to late tm,, the covalcney increases and u get a larger TN(k)

Question 23

ferromag

Answer 23

aligned

Question 24

antiferro mag

Answer 24

not aligned ,, they cancel out

Question 25

ferri mag

Answer 25

not alligned but there is still a net magnetism bc one arrow is larger than the one in the opposite direction

Question 26

when we have the solid things,, we used to do in second year,, what do we need to remember about the atoms in the corners of the cube etc

Answer 26

we needd to think that these have a lower contribution as theyre kinda shared between a bunch of things wheras the ones in the middle will have a larger contribution due to them being 100% in one bit.

Question 27

there may be more antiferro than ferro but what else do we need to look at

Answer 27

we need to look at the contribution of each one,, aka if theres more ferro but these have a smaller contribution than the antiferro,, there could be ferri magentism,, aka theyre opposed but theres still net magnetism!!