In an octahedral ligand arrangement, how are meridional isomers positioned relative to the metal ion?

In an octahedral ligand arrangement, meridional isomers are specifically characterized by the configuration of their ligands relative to the central metal ion. In this case, "meridional" refers to the ligands being arranged along a specific plane or line that divides the octahedral geometry.

The correct answer indicates that the ligands in meridional isomers are aligned along the metal ion's meridian. This means that one set of like ligands is positioned to form a plane that passes through the center of the octahedron and bisects it. For instance, in a meridional isomer of a complex with two pairs of identical ligands, one pair will occupy positions that are closer together and symmetrical, lying along the axis that runs through the center of the metal ion, directly representing the idea of a "meridian."

In octahedral complexes, ligands can be arranged in two basic forms: meridionally and facially. In facial isomers, the ligands are oriented in such a way that they occupy the corners of a triangle on one face of the octahedron, while meridional isomers see the ligands in a straighter alignment along the central axis.

This unique arrangement is