ethylenediaminetetraacetato (edta)

[Noah Carey 1G]

Why is ethylenediaminetetraacetato (edta) not octadentate? There are two additional Oxygen atoms that have double bonds and therefore two lone pairs each. These pairs do not interact with the metal. Is it because the shape can't reach those two Oxygen atoms? Oxygen atoms with a formal charge of 0 can share the lone pairs in a coordination complex too, right?

[jadam_1E]

Hi Noah,

A double bond is made of a sigma bond and a pi bond. Because of the pi bond, any atom with a double bond cannot rotate or bend--it is fixed so to say. This inability of the atom to reach toward the central metal atom prevents it from binding. So, the two oxygens in EDTA that have double bonds do not contribute to the total number of donor atoms and EDTA is hexadentate.

[Chem_Mod]

Yes. the two additional oxygen atom is geometrically constrained to form coordinate to the metal.

[Anthony Mercado 1K]

What is the critical importance of edta? *I have been hearing this term a lot recently, and I was wondering if someone could explain the composition of edta, and the properties it has

[jadam_1E]

edta is very important for one thing because it is the most common hexadentate ligand, meaning it can bind to a central metal atom in up to 6 locations.

[Chem_Mod]

edta binds to almost all heavy metals. So it has uses in experiments and applications where metal ions are not desired.

[nikitasridhar_1b]

do we need to memorize the formula for edta?