crystal field theory Flashcards
what is the CFSE
(the crystal field stabilisation energy)
in an octahedral system, the dz2 and dx2-y2 point directly at the ligands donor electrons (they are on the axis) which are raised in energy due to the electrostatic repulsions.
what does e mean ?
there are 2 orbitals within the set. (dz2, dx2-y2)
what does g mean ?
that a invention of the molecule would take us back to where we started e.g. no change
what does t mean?
3 orbitals within the set (dxy, dxz, dyz)
what is the energy gap between the 2 sets of d orbitals called
crystal field splitting energy
how much are the eg orbitals changed by
+0.6
how much are the t2g orbitals changed by
-0.4
what explains the unsmooth trend in ionic radii
when there is an excess of weakly repelling electrons in the t2g set, compared then when they are both even.
lower energy =
smaller radius
how do you calculate the CFSE
(d-electrons in eg level x 0.6) - (d-electrons in t2g level x 0.4) + (deltaP)
what is delta P
the difference in the number of electron pairs between the 2 forms
what is hunds rule
every orbital in a sub shell must be singly occupied before doubly occupied.
what is aufbaus principle
electrons should fill orbitals of the lowest energy before occupying higher levels
spin pairing will occur if ….
the energy cost to pair 2 electrons (P) is lower than deltaO
higher oxidation states for the same metals have a …
larger deltaO
the colour that we see of transition metals is the sum of the light ..
not absorbed by the complex as its complimentary
what is the beer lambert law?
it related absorbance to the solution concentration
what is E
the molar extinction coefficient - it indicated the intensity of an absorption.
what is magnetic momentum
the fact that unpaired electrons behave like magnets
what is magnetic susceptibility used for
to tell is a complex is high or low spin - also to indicate the geometry
a complex is high spin if …
deltaO > p
a complex is low spin if …
deltaO < p
what is the equation for the number of unpaired electrons
n = ✔️(u^2 + 1) -1
what is the equation for the magnetic momentum for spin only systems
u = ✔️4S(S+1) where S = 1/2
what is the equation for the magnetic spin momentum when we know n
u = ✔️n(n+2)
