Definition: Hapticity (denoted by η) refers to the number of contiguous atoms of a ligand that are directly coordinated to a central metal atom
.Analysis:
The 18-electron rule states that thermodynamically stable transition metal organometallic compounds are formed when the sum of the metal's valence electrons plus the electrons donated by the ligands equals 18, achieving the noble gas configuration.
Examples:
Ferrocene Fe(C₅H₅)₂ exists in two main conformations
:Molecules:
2. (a) (ii) 16-electron species: Wilkinson's Catalyst [RhCl(PPh₃)₃].
Grignard reagents are prepared by the reaction of an alkyl or aryl halide with magnesium metal in the presence of dry ether
.R-X + Mg → R-Mg-X (in dry ether)
Dry ether acts as a solvent and a Lewis base that stabilizes the Grignard reagent through coordination with the magnesium atom
. "Dry" (anhydrous) conditions are essential because Grignard reagents are highly reactive and will react with water to form alkanes.The trans-effect is the labilization of a ligand trans to a certain other ligand (the trans-director) in square planar complexes, which speeds up the substitution of that trans-ligand.
It is called a homogeneous catalyst because the catalyst and the reactants (alkene and H₂) are in the same phase (liquid/solution) during the reaction
.Hybridization: dsp²
.Geometry: Square Planar
.The Solubility Product (Ksp) is the equilibrium constant for a solid substance dissolving in an aqueous solution
. Precipitation occurs when the Ionic Product (Q) exceeds the Ksp (Q > Ksp).