C

Coordination Compound or Complex

[ML_n]^x; IUPAC name: [ligands alphabetically, metal, charge]
Quick Reference
Formula / Notation[ML_n]^x; IUPAC name: [ligands alphabetically, metal, charge]
Also Known AsCoordination complex, metal complex, Werner complex, ligand complex

What is Coordination Compound or Complex?

A coordination compound (or complex) consists of a central atom or ion (usually a transition metal) surrounded by a set of ligands bonded to it through coordinate covalent bonds. The central atom and its ligands form the coordination sphere. Coordination compounds are important in catalysis, bioinorganic chemistry (e.g., haemoglobin), and analytical chemistry.

Formula & Notation

[ML_n]^x; IUPAC name: [ligands alphabetically, metal, charge]

Other Names / Synonyms: Coordination complex, metal complex, Werner complex, ligand complex

Properties & Characteristics

A coordination compound (or complex) consists of a central metal atom or ion surrounded by ligands (molecules or ions) that form coordinate bonds with it. The number of donor atoms bonded to the metal is the coordination number (typically 2, 4, or 6). Coordination compounds have distinctive colours, magnetic properties, and geometries (octahedral, tetrahedral, square planar). Werner's coordination theory (1893) laid the foundations.

Uses & Applications

Coordination compounds are used as catalysts (Wilkinson's catalyst [RhCl(PPh₃)₃], Ziegler-Natta catalysts), in medicine (cisplatin, carboplatin, EDTA chelation therapy), analytical reagents (EDTA, ferroin), dyes (phthalocyanine pigments), and in extractive metallurgy (gold cyanidation).

Safety Information

Many coordination compounds contain toxic metals (Hg, Pt, Cd, Cr) or toxic ligands (CN⁻, CO). Cyanide-containing coordination compounds can release HCN in acidic conditions. Platinum compounds cause nephrotoxicity and allergic sensitisation. Always consult SDS for specific compounds.

Always consult the SDS/MSDS before handling any chemical. This information is for educational purposes only.

Key Facts

Term Coordination Compound or Complex
Formula [ML_n]^x; IUPAC name: [ligands alphabetically, metal, charge]
Synonyms Coordination complex, metal complex, Werner complex, ligand complex

Frequently Asked Questions

A coordination compound (or complex) consists of a central atom or ion (usually a transition metal) surrounded by a set of ligands bonded to it through coordinate covalent bonds. The central atom and its ligands form the coordination sphere. Coordination compounds are important in catalysis, bioinorganic chemistry (e.g., haemoglobin), and analytical chemistry.

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