What is EDTA and how is it different from a single machine ligand

It doesn't have to be that complicated.

Ethylenediaminetetraacetic acid is generally used in experiments with its disodium salt, i.e., disodium EDTA, to increase solubility.

Unlike single-unit ligands, EDTA is a six-toothed ligand chelator, so it forms a 1:1 complex quantitatively with metal ions and binds tightly.

What's more, because it is a multi-tooth ligand, there is no step-by-step complexation, which is good for quantitative analysis.

Ethylenediaminetetraacetic acid.

Mats one-to-one with most metal ions (regardless of the number of valence ions).

With a few exceptions, such as pentavalent molybdenum 1:2

1 EDTA has a wide range of coordination properties and can be almost identical to.

All metal ions form complexes.

Therefore, coordination titration is widely used, but how to improve the selectivity of titration has become an important problem in coordination titration.

The coordination ratio of 2 EDTA complexes is simple, and in most cases, 1 1 complexes are formed. Individual ions such as Mo( ) and EDTA complexes [(MoO2)2Y2-] have a coordination ratio of 2 1

3 EDTA complexes have high stability and can form chelates with metal ions with multiple five-membered ring structures.

4 EDTA complexes are easily soluble in water, enabling coordination reactions.

Faster. 5 Most metal-EDTA complexes are colorless, which facilitates the determination of endpoints by indicators. However, the color of the chelate formed by the coordination of EDTA and non-ferrous metal ions is deepened. For example:

cuy 2- niy 2- coy 2- mny 2- cry- fey-

Dark blue, blue, purplish-red, purple-red, dark purple, yellow.

Cation. lgkmy cation lgkmy cation lgkmy

na＋ ce4＋ cu2＋

li＋ al3＋ ga2＋

ag＋ co2＋ ti3＋

ba2＋ pt2＋ hg2＋

Mg2 CD2 slippery sn2

sr2＋ zn2＋ th4＋

be2＋ pb2＋ cr3＋

ca2＋ y3＋ fe3＋

mn2＋ vo＋ u4＋

fe2＋ ni2＋ bi3＋

la3＋ vo2＋ co3＋

Therefore, when titrating these ions, it is important to control their concentration not to be too large, otherwise it will be difficult to determine the endpoint using the state indicator.

EDTA generally refers to ethylenediaminetetraacetic acid.

Ethylenediaminetetraacetic acid is an organic compound with the chemical formula C10H16N2O8, which is a white powder at room temperature and pressure. It is a chelating agent that can bind to divalent metal ions such as Mg2+, Ca2+, Mn2+, Fe2+, etc.

Because most nucleases and some proteases require Mg2+, they are often used as inhibitors of nucleases and proteases; It can also be used to remove the inhibition of enzymes by heavy metal ions.

Unlike single-unit ligands, EDTA is a six-toothed ligand chelator, so it quantitatively forms a 1:1 complex with metal ions. Moreover, it is tightly bound, and more importantly, because it is a multi-tooth ligand, there is no step-by-step complexation, which is conducive to quantitative analysis.

EDTA is an important complexing agent. EDTA has a wide range of applications and can be used as a bleaching fixer for the processing of color photosensitive materials, a dyeing aid, a fiber treatment aid, a cosmetic additive, a blood anticoagulant, a stabilizer, and a polymerization initiator for synthetic rubber. It can form stable water-soluble complexes with alkali metals, rare earth elements and transition metals.

In complexes, the ions or molecules that bind to the central ion or atom with a coordination bond are called ligands. For example, the NH3 molecule in [Cu(NH3)4]2+. They become the inner bounds of the complex with the central atomic structure.

Common ligands are ammonia molecules, water molecules, hydroxide ions, halogen ions, cyanogen ions, and cyano ions.

The above-mentioned ligands are all single-base ligands. Single-base ligands contain only one coordination atom and form only one coordination bond with the central ion, and their composition is relatively simple. Multimatrix ligands contain two or more coordination atoms, which can form multiple coordination bonds with central ions or atoms, and their composition is often more complex, and most of them are organic compounds.

Common multi-base coordination positions include ethylenediamine denoted by EN, oxalate (denoted by ox), ethylenediaminetetraacetic acid (EDTA), and butadixime (HDMG).