What composes a coordination complex?

A coordination complex is primarily composed of a central metal atom or ion bonded to surrounding molecules or ions known as ligands. Ligands are species that can donate pairs of electrons to the metal atom, typically containing lone pairs that facilitate the formation of coordinate covalent bonds. This structure is crucial as the properties and reactivity of coordination complexes largely depend on the nature of both the central metal and the ligands involved.

The formation of coordination complexes is a fundamental concept in coordination chemistry, which plays an important role in various branches of chemistry, including bioinorganic chemistry and industrial catalysis. In contrast, the other options do not accurately represent the composition of a coordination complex. A single atom in isolation would not involve ligands, while a large number of unrelated ions does not reflect the specific, coordinated arrangement characteristic of a coordination complex. A mixture of solid and liquid substances fails to capture the idea of a defined bonding interaction between a central atom and its ligands.