Polydentant ligands contain more co-ordination points (can give more electron pairs) and they form complex ringlike structures (celate complexes) by replacing two or more monodentant ligands. That kind of ligand is EDTA which has 6 co-ordinational points and with metals it creates complexes, always in 1:1 ratio.
Generalic, Eni. "Polydentant ligand." Croatian-English Chemistry Dictionary & Glossary. 29 June 2022. KTF-Split. 1 Apr. 2025. <https://glossary.periodni.com>.
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Periodic Table