Preferred Label : apicophilicity;
IUPAC definition : In trigonal bipyramidal structures with a five-coordinate central atom, the stabilization
achieved through a ligand changing its position from equatorial to apical (axial).
The apicophilicity of an atom or a group is evaluated by either the energy difference
between the stereoisomers (permutational isomers) containing the ligand in apical
and equatorial positions or the energy barrier to permutational isomerization (see
also Berry pseudorotation). In general, the greater the electronegativity and the
stronger the π-electron-withdrawing properties of a ligand (as for Cl, F, CN), the
higher is its apicophilicity. The notion of apicophilicity has been extended to four-coordinate
bisphenoidal and three-coordinate T-shaped structures, which can be viewed as trigonal
bipyramidal species where, respectively, one or two vertices are occupied by phantom
ligands (lone electron pairs).;
Origin ID : AT06990;
See also
In trigonal bipyramidal structures with a five-coordinate central atom, the stabilization
achieved through a ligand changing its position from equatorial to apical (axial).
The apicophilicity of an atom or a group is evaluated by either the energy difference
between the stereoisomers (permutational isomers) containing the ligand in apical
and equatorial positions or the energy barrier to permutational isomerization (see
also Berry pseudorotation). In general, the greater the electronegativity and the
stronger the π-electron-withdrawing properties of a ligand (as for Cl, F, CN), the
higher is its apicophilicity. The notion of apicophilicity has been extended to four-coordinate
bisphenoidal and three-coordinate T-shaped structures, which can be viewed as trigonal
bipyramidal species where, respectively, one or two vertices are occupied by phantom
ligands (lone electron pairs).
