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Guilherme Mazui

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What is the Difference Between Coordination Compound and Complex Ion?

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Coordination compounds and complex ions are related but distinct concepts in coordination chemistry. The key difference between them lies in their charge: coordination compounds can be charged or uncharged, while complex ions are charged species.

  • Coordination Compound: A coordination compound is a compound containing one or more metal complexes, where the central metal atom or ion is bonded to one or more ligands. Ligands are ions or molecules that contain one or more pairs of electrons that can be shared with the central metal atom or ion. Coordination compounds can be either neutral or charged, depending on the specific composition and reaction conditions. Some examples of coordination compounds include Ni(CO)4 and K4[Fe(CN)6].
  • Complex Ion: A complex ion is formed from a metal ion and a ligand due to a Lewis acid-base interaction. The positively charged metal ion acts as a Lewis acid, and the ligand, with one or more lone pairs of electrons, acts as a Lewis base. Complex ions are electrically charged species. Some examples of complex ions include the hexaaquarion(III) ion [Fe(OH2)6]3+ and the hexacyanoferrate(III) ion [Fe(CN)6]3-.

In summary, coordination compounds can be charged or uncharged and contain one or more metal complexes with central metal atoms or ions bonded to ligands. Complex ions are charged species resulting from the interaction between a metal ion and a ligand.

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  • What is the Difference Between Coordination Compound and Complex Ion?
  • Comparative Table: Coordination Compound vs Complex Ion

    • Comparative Table: Coordination Compound vs Complex Ion

    Here is a table comparing coordination compounds and complex ions:

    Feature Coordination Compounds Complex Ions
    Definition Coordination compounds consist of a ligand and a metal center cation, with the overall charge being positive, negative, or neutral. Complex ions are ions with a central metal ion and one or more ligands, which can be molecules or ions.
    Structure Coordination compounds can have various structures, depending on the coordination number and ligands. Complex ions have a specific structure, with the central ion coordinated by ligands.
    Coordination Number The coordination number is the number of places on the metal ion where ligands are bound. The coordination number is also applicable to complex ions, as they share the same structure with coordination compounds.
    Charge Coordination compounds can have positive, negative, or neutral charges. Complex ions can carry charges, depending on the charges of the central ion and ligands.
    Examples - Complex Cation: $$\ce{[Co(NH3)6]^{3+}}$$
    - Complex Anion: $$\ce{[CoCl4(NH3)2]^{-}}$$
    - Neutral Complex: $$\ce{[CoCl3(NH3)3]}$$.    		 - Complex Ion: $$\ce{Ag(NH3)2+}$$ (Silver complex ion with 2 as coordination number).

    Both coordination compounds and complex ions involve a central ion (usually a transition or inner transition metal) surrounded by one or more ligands, forming coordinate (dative covalent) bonds. The main difference between the two is that coordination compounds can have different overall charges, while complex ions are ions with a specific charge.

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    Guilherme Mazui

    Guilherme Mazui is graduated in journalism from the Federal University of Minas Gerais (UFMG) and a master's degree in Communication from the University of São Paulo (USP). In addition, he has experience in advertising writing and has worked as a content editor in several companies.