F-Block Flashcards
F-Orbitals
4f n = 4. l = 3 ml = -3, -2, -1, 0, 1, 2, 3 ms = +1/2, -1/2 degeneracy 2l+1 = 7 nodes n -1 = 3 radial n - l - 1 = 0
Radial Distribution Function Ln
no radial nodes 4f close to nucleus, probability of electrons close to the nucleus poor shielding core-like electrons poor overlap with ligands ionic bonding
Radial Distribution Function Ac
one radial node probability further from nucleus less core-like more expansive better overlap with ligands covalent bonding
Down a Group
increased size
decreased ionisation energies
Across a Period
decreased size
increased ionisation energies
increased Zeff
4f and 5f Trends
radii drastically decrease across a period
Ln/Ac contraction
poor screening of f-electrons
4f feels increased nuclear charge
Relativistic Effect
electrons moving in vicinity of highly charged nucleus
approach speed of light
velocity increases so does J and mass
Spectroscopic Properties
weak narrow bands
forbidden f-f transitions
no crystal field effect
Coordinating Ln
ionic bonding hard donor ligands needed N/O/F high coordination number large ionic radii strong chelate/macrocyclic effects entropy increased on displacing water for multidentate ligands
NMR Shift Reagents
Ln3+ coordinated to Lewis base
separate race if mixture into enantiomers
determine e value
paramagnetic - induces change in chemical shift
MRI Contrast Agent
contrast between H and H2O I’m healthy and diseased tissues
cancerous tissues - longer relaxation time
Gd- low toxicity when chelated, high magnetic moment, soluble
Ln Probes
Ln3+ similar size to Ca2+
substitute in biological systems
luminescence
Coordinating Ac
not highly available radioactive toxic U and Th RN2-
Ac in Nuclear Fuel
rods dissolved in HNO3
separation of U and Pu on stability
processed to AnO2
Alkyl
prone to nucelophilic attack
kinetic ally unstable unless with bulky ligands
agostic interactions hard to detect - paramagnetic
