a coordinate or cordination complex is a compound comprised of a central ion (normally a metal Eg. Fe3+) the atoms that are bonded to it are called ligands. The coordination number is the number of donor atoms bonded to the central atom. Interestingly if the coordination number is for example 4, in a monodentate ligand this would mean theat there would need to be 4 ligands, however in a bidendate ligand there would only need to be two (with each ligand providing 2 donor atoms each). There is more nuance to coordination chemistry that I may elaborate on in the future but it likely needs its own tab on in [[Chemistry and co]] which will hopefully get done eventually (22/07/2025)