Andy Burrows Flashcards
What are the most common oxidation states of Sc
+3
What are the most common oxidation states of Ti
+3 & +4
What are the most common oxidation states of V
+5
+4
+3
What are the most common oxidation states of Cr
+6
+3
What are the most common oxidation states of Mn
+7
+3
+2
What are the most common oxidation states of Fe
+3
+2
What are the most common oxidation states of Co
+3
+2
What are the most common oxidation states of Ni
+2
What are the most common oxidation states of Cu
+2
+1
What are the most common oxidation states of Zn
+2
What structures do MO2 have
Rutile
What structures do M2O3 have
Corundum
What structures do MO have
Rock salt
What structures do M3O4 have
Spinel
Why do Ti4+ compounds have high covalent character
High charge density on the metal make it very polarisable
How are half equations usually represented
As reductions with the higher oxidation state on the left hand side
What is implied by a greater value of E(potential)
The greater the strength of the oxidising agent on the left and the weaker the reducing agent on the right
How can you calculate the E (potential) between two points on a frost diagram
Gradient of the line between two points
Is disproportionation more or less favourable if the intermediate oxidation state lies below the line linking the higher and lower oxidation states
Thermodynamically unfavourable
Is disproportionation more or less favourable if the intermediate oxidation state lies above the line linking the higher and lower oxidation states
Thermodynamically favourable
How does pH affect oxidation states
Greatly
High pH favours higher oxidation states
Facts about Sc
Colourless
Sc3+ is a strong Lewis acid
Borderline transition metal chemistry
Give facts about Ti
Strong Lewis acid
Can be reduced to Ti3+
Ti3+ is a good reducing agent
What colour is V6+
Blue
What colour is V3+
Green
What colour is V2+
Violet
What shape are most VO^2+ complexes
Square pyramidal
Why does V2+ need to be handled in an inert atmosphere
Strongly reducing and oxidised by air
Chromium facts
Cr6+ is strongly oxidising
Cr2+ is strongly reducing
Cr3+ is d3 so has a high CFSE therefore kinetically inert
Carboxylate are dimeric and contain Cr-Cr multiple bonding
Manganese facts
Mn 7+ is a powerful oxidising agent. It exists as a tetrahedral anion. It is intensely coloured due to the L to M charge transfer band
Mn3+ is always a distorted tetrahedral due to the Jain teller effect
Mn2+ are weakly coloured due to the forbidden d to d transition
Why is Fe3+ acidic in solution?
High charge density on metal increases the lability of the protons
Why are compounds between Fe 3+ and Fe2+ strongly coloured
M to M charge transfer bands
Cobalt facts
Cobalt 3+ is a strong oxidising agent
N donor ligands great
Y stabilise Co3+
Zinc facts
Only important oxidation state is Zn2+
Colourless with a wide range of geometries
Not really a transition metal
What symmetry does a 4s orbital have?
A1g
What symmetry do 4p orbitals have?
T1u
What symmetry do the d orbitals have (squared)
Eg
What symmetry do the d orbitals have (unsquared)
T2g
Do pi donor ligands increase or deserves delta Oct
Decrease
Do pi acceptor ligands increase or deserves delta Oct
Increase
What is the role of a metal centre in the electron transfer of proteins?
Provide a reversible site for an electron
What are cytochromes
Iron haem proteins
What is the role of cytochrome c
Transfer electrons from c1 to cytochrome c oxidase
What are oxidises
Enzymes that use oxygen as an electron acceptor
What ions are hard metals(acids)
Li+ Na+ K+ Mn2+ Al3+ VO^2+
What ions are soft metals (acids)
Ti+ Ag+ Cu+ Pb+ Pt+ Pd2+
What ions are hard ligands
F- Cl- Oh2 OR- Nh3
What ions are soft ligands
I-
CN-
SR-
PR3
