lecture 9🅱️ Flashcards
whats MO
metal oxide
delta H lat is what when it comes to metal oxides
delta H lat is the lattice enthalpy
M2+ (g) + O2- (g) –> MO(s)
1st row MO have what structure
they have NaCl structure
a salt structure
Oh around the metal
what coordination geom does NaCl have around the Metal
Oh coordination around the Metal.
what is Oh
octahedral
what is the total magnetic moment made up of
spin motion (s and S)
angular motion (l+L)
what gives free atoms // ions magnetism
the spin and angular motion
quantum numbers for spin motion
s and S
quantum number for angular motion
l and L
what is the magnetic moment
the number of unpaired electrons there is per mole.
long u.eff
what does knowing the number of unpaired electrons help us know
spin state
coordination geometry
oxidation state
explain weak field
high spin
small splitting
when delta o < P
what is S
S is total spin
how do we find S value
number of unpaired electrons x (1/2)
bc spin of an e- is 1/2
whats long U.so
this is the spin only magnetic moment
equation to find u.so aka spin only magnetic moment and what does each letter mean
g root S(S+1)
g = gyromagnetic ratio of one e-
S = total spin (number of unpaired e- x 1/2)
what do we normally set g: the gyromagnetic ratio of an e- in the spin only magnetic moment equation to
we set it to 2
so we get 2 root S(S+1) for the spin only magentic number value.
whats the spin only magnetic moment for smt that is high spin d6
number of unpaired e- = 4
S = 4 x 1/2
S = 2
u.so = g root 2(2+1)
= 2 root 2(2+1)
= 4.9BM (bohr magnetrons)
when is the spin only magnetic moment a good approx
when ur applying it to some first row transition elements,, not to all of them
which ions have no 1st order orbital contribution,, (spin only magnetic moment) and why
ions with A or E ground terms
bc their higher energy T twrms can mix + contribute
D –> E+T
F –> T+T+A
how do we figure out which term an ion is
we look at the electron config (the t2g // eg version) of its ground state and see how many equivalent ways there is to draw each one
aka if theres a d1 ion,, theres 3 t2g’s,, and the 1e- ,, if in its ground state,, can go into either one of the 3 t2g’s
so bc theres 3 different options,, we say it is the T term,, and that its triply degenerate
whats an T term
the e- can go in 3 diff degenerate orbitals.
its equally likely to go into any of them
whats an A term
when theres just 1 degenerate way of filling in the e- config
whats an E term
when theres 2 different ways of drawing the electrons config.
aka high spin d4 (bc theres 2 eg’s it can go into)
T
triply degenerate
2 degenerate ways
A
1 way
singly degenerate
or non degenerate
E
doubly degenerate
2 degenerate ways
what ground state terms will we observe the spin only magnetic moment
the A and E terms will let us observe spin only magnetic moments.
what is present in some T term ions
sometimes there is some obrital contribution present
this means the e- will orbit the metal nuc
which ground terms have an orbital contribution
those that are T term,, aka triply degenerate
what do T terms show in tetrahedral molecules,, Td
they show temperature dependant paramagnetism
what is L
the total orbital angular momentum
how can L aka orbital angular momentum be reduced // quenched
by applying a ligand field to it
where does the spin only formula work well for
it works well for the 1st row of transition elements,, doesnt work as wel lfor the 2nd and 3rd ones.
which orbitals interact very weakly to the applied ligand field
F orbitals,, aka the F block orbitals interact very weakly with the ligand field
if the f obritals barely interact with the ligand field,, what does that mean about its orbital angular moment
it means that it is basically unquenched.
bc if its not interacting with the ligand field,, its not being reduced,, so its remaining the same.
magnetic moment for spin and anfgular momentum
U.S+L =
root 4S(S+1) + L(L+1)
geomteries with lower symmetry include what geom
tetrahedral geometries
such as Td geometries
what bonding can we not separate in Td
we cant separate sigma and pi bonding
why is there no g subscript in Td energy levels
bc they have no inversion centre
theres no gerade aka symmetric element.
phases chnage when u go across the molecule.
what bonding is important in Td complexes
pi bonding is very important in Td complexes.
delta T is smaller or larger than delta O
its smaller,,
its 4/9 smaller than delta O
why is delta T splitting less than delta O splitting
bc theres less ligands bonded to the metal
and its geometry is different
larger delta T values give rise to what geometry
they give rise to trigonal planar geometry.
to go from octahedral to trigonal bipyramidal,, what must happen
u most lose a ligand. to go from 6 to 5 of them
describe the trigonal bipyramidal structure
dz^2: points at all ligands meaning its extremely high in energy and antibonding
dxy, dx^2-dy^2 : middle energy,, points at 1 ligand each: non bonding?
dxz, dyz : least amount of energy,, not pointing at any ligands,, bonding
describe trigonal bipyramidal based on the dz^2 orbital
its the metal basically,, u have the donut and the 2 lobes coming out of it.
and the 2 lobes and donut are diff phases and count as the metal. then theres 5 ligands pointing out of it in their normal trigonal bipyramidal way.
