HSAB theory and its applications Flashcards
What does the Irving-Williams series tell you?
the relative stability of the complexes formed by metals
What is the order of stability of M²⁺ complexes according to the Irving-Williams series?
Ba < Sr < Ca < Mg < Mn < Fe < Co < Ni < Cu > Zn
Which M²⁺ has the strongest complexes?
Cu²⁺
What happens along the Irving-William series?
The ionic radius gets smaller
Why does the stability increase as the ionic radius gets smaller?
The binding of ligand to metal gets tighter and feels more of the effective nuclear charge
What metals are metals in a complex able to be displaced by?
metals which are higher up on the series than itself
What can lewis acids and bases be classed as?
Hard or soft
What type of bases do hard acids prefer?
Hard bases
What type of bases do soft acids prefer?
Soft bases
What is the atomic or ionic radius like on a hard atom?
Small
What is the atomic or ionic radius like on a soft atom?
Large
What is the oxidation state like on a hard atom?
High
What is the oxidation state like on a soft atom?
Low
What is the polarisability like on a hard atom?
Low
What is the polarisability like on a soft atom?
High
What is polarisability?
How much does an ion change its shape when interacting with another charge
What is electronegativity like on a hard base?
High
What is electronegativity like on a soft base?
Low
What is ion solvation like for a hard atom?
High
What is ion solvation like for a soft atom?
Low
What is bonding orbital energy like for a hard atom?
High
What is bonding orbital energy like for a soft atom?
Low
What type of bonding is present for hard atoms?
Electrostatic (ionic)
What type of bonding is present for soft atoms?
Covalent
Where are atoms harder?
If they are higher up in a group
What are some examples of hard lewis acids?
H+
Alkali metals
First row TM
Group 13 elements
What are some examples of soft lewis acids?
Heavier TM
Most other main group metals
What happens to metals as you go down a group ?
They get softer
What are some examples of hard lewis bases?
Light elements N, O F Amines Ethers Halogens F-, Cl-
What are some examples of soft lewis bases?
They have an excess of electrons, eg. lone pairs SCN- Br- , I- CO C6H6
What happens to the bases as you go down a group?
They become softer
What is the trend of K of a soft metal?
Upward trend
Increases from hard to soft
What is the trend of K of a hard metal?
Downward
decreases from hard to soft
What do bonds between hard lewis acids and bases tend to be?
Ionic
What do bonds between soft lewis acids and bases tend to be?
Covalent
Is HSAB thermodynamic or kinetic?
Thermodynamic
What happens when you coordinate ligands to hard lewis acids?
Make them stronger brønsted acids
What happens when you coordinate ligands to soft lewis acids?
Makes them stronger brønsted bases
