When salicylic acid forms a purple complex with iron(III) ions, what does the complex look like?
Igloo replies Salicylic acid molecules are bidentate. Iron(III) ions usually show a coordination number of 6 in their complexes. In practice it is the conjugate base of salicylic acid which acts as the ligand, i.e. HOC6H4COO-, rather than HOC6H4COOH. The formula of the complex is therefore [Fe(HOC6H4COO)3] and its shape is octahedral. For diagram of what this complex looks like, go to the Chemguide website. Scroll half way down the page to the sub-heading Optical Isomerism for diagrams to help you visualise the shape of the complex. Risk assessment Before attempting any practical work based on the advice and suggestions on this website, you must do the following. Identify any hazards, assess the risks from these hazards, and then decide appropriate control measures to reduce the risks. You must have these approved by those in authority in your school or college laboratory. Do not rely on what is said on this website. For further guidance see our tutorial on Risk Assessment.
