Composition of a coordination A Lewis acid,.called形成体(eg,central metal ion): A Lewis base,.called配位体(ligand). Central metal ion(形成体)usually are metals and metal ions,also have few nonmelal .Such as Cu2+,Agt,Fe3+, Fe,Ni,Bm,PV.… Ligand(配位体)in classical coordination chemistry bind to metals,almost exclusively,via their "lone pairs"of electrons residing on the main group atoms of the ligand. Typical ligands are:F-,CI,Br,I,OH-,CN-,H2O, NH3,:C0,H2C=CH2.… Central metal ion(形成体) usually are metals and metal ions,also have few nonmelal .Such as ：Cu2+，Ag+ ，Fe3+， Fe，Ni，BⅢ，PⅤ …… Ligand(配位体) in classical coordination chemistry bind to metals, almost exclusively, via their “lone pairs” of electrons residing on the main group atoms of the ligand. Typical ligands are：F－, Cl－, Br－, I－, OH－, CN- , H2O, NH3 , :CO, H2C=CH2…… A Lewis acid, called形成体(e.g., central metal ion)； A Lewis base, called 配位体 (ligand). Composition of a coordination