Which is the role of the d or f electrons in the characterized properties of hard acid and soft acid?
Answers
Answer:
Answer:
According to HSAB concept, hard acids prefer binding to the hard bases to give ionic complexes, whereas the soft acids prefer binding to soft bases to give covalent complexes. It is sometimes referred to as Hard-Soft Interaction Principle (HSIP)
it was found that the right side is favored when the Lewis acids and bases are only weakly polarizable: in other words, their electron shells are not easily deformed.
This led to the hard and soft acid and base (HSAB) concept. Other things being approximately equal:
hard acids react faster with hard bases and form stronger bonds with them
soft acids react faster with soft bases and form stronger bonds with them
HSAB is a qualitative guide to reactions; it is not a quantitative, numerical method.
Hard Acids and Bases
Hard acids consist of small highly charged cations and molecules in which a high positive charge can be induced on the central atom.
Examples of Hard Acids: H+, Li+, K+, Ca2+, Al3+, Sn4+, BF3, BCl3, CO2, RCO+, SO3, RMgX, VO2+, AlCl3
Hard bases are highly electronegative and of low polarizability.
Examples of Hard Bases: F-, OH-, NH3, N2H4, ROH, H2O, SO42-, PO43-
Hard bases react more readily to form stable compounds and complexes with hard acids.
Soft Acids and Bases
Soft acids consist of large low charge cations and molecules with relatively high energy occupied molecular orbitals. Soft acids are readily polarizable.
Examples of Soft Acids: Cs+, Cu+, Au+, Pt2+, Hg+, BH3, Br2, I2, RO+, quinones
Hard bases have low electronegative and low polarizability.
Examples of Soft Bases: H-, R-, CO, PR3, C6H6, SCN-
Soft bases react more readily and form stable compounds and complexes with soft acids.
Click link for Further Examples of Hard and Soft Acids and Bases