Ethylenediaminetetraacetic acid
Strong Chelating Ability: EDTA exhibits hexadentate chelation, forming highly stable coordination compounds through six-point binding with metal ions.
Effective Ligand: It functions as a potent polydentate ligand, enabling widespread use in industrial and laboratory settings for metal ion complexation.
Wide Application Range: This compound finds utility across diverse sectors including water treatment, pharmaceutical manufacturing, agricultural formulations, and as a specialty additive in chemical processes.
Chemical Stability: EDTA maintains structural integrity at elevated temperatures (up to 250°C) and demonstrates resistance to decomposition, ensuring reliability in demanding applications.
Ethylenediaminetetraacetic Acid (EDTA) functions as a highly effective polydentate ligand in aqueous systems. In solution, EDTA undergoes deprotonation to generate the EDTA⁴⁻ anion, which contains six potential coordination sites—four oxygen atoms from carboxylate groups and two nitrogen atoms from amine groups—capable of simultaneous interaction with metal ions.
Ethylenediaminetetraacetic acid Chemical Properties
Melting point | 250 °C (dec.) (lit.) |
Boiling point | 434.18°C (rough estimate) |
bulk density | 600kg/m3 |
density | 1.46 g/cm3 at 20 °C |
vapor pressure | <0.013 hPa (20 °C) |
refractive index | n20/D 1.363 |
Fp | >400°C DIN 51758 |
storage temp. | 2-8°C |
solubility | 3 M NaOH: 100 mg/mL |
form | crystalline |
pka | pKa 2 (Uncertain);10.26 (Uncertain) |
color | White to almost white |
PH | 2.5 (10g/l, H2O, 23℃)(slurry) |
Odor | Odorless |
PH Range | 2.5 at 10 g/l at 23 °C |
Water Solubility | 0.5 g/L (25 ºC) |
λmax | λ: 280 nm Amax: ≤0.25 |
Decomposition | 240 °C |
Merck | 14,3517 |
BRN | 1716295 |
Stability: | Stable. Incompatible with copper, copper alloys, nickel, aluminium, strong oxidizing agents, strong bases |
LogP | -0.836 (est) |
CAS DataBase Reference | 60-00-4(CAS DataBase Reference) |
NIST Chemistry Reference | N,N'-1,2-Ethane diylbis-(N-(carboxymethyl)glycine)(60-00-4) |
EPA Substance Registry System | Ethylenediaminetetraacetic acid (60-00-4) |
Safety Information |
Hazard Codes | Xi |
Risk Statements | 36-52/53-36/37/38-36/38 |
Safety Statements | 26-61-37/39-36 |
RIDADR | UN 3077 9 / PGIII |
WGK Germany | 2 |
RTECS | AH4025000 |
F | 3 |
Autoignition Temperature | >200 °C |
TSCA | Yes |
HS Code | 2922 49 85 |
Hazardous Substances Data | 60-00-4(Hazardous Substances Data) |
Toxicity | LD50 orally in Rabbit: 2580 mg/kg |
During chelation, the EDTA anion envelops metal ions through these six binding sites, forming exceptionally stable coordination complexes. This multidentate binding mode creates a forcipate that tightly encapsulates the metal center, analogous to the grasping action of a crustacean's claw—the phenomenon from which the term "chelation" derives its etymological origin. The exceptional stability of EDTA-metal complexes arises directly from this maximized coordination capacity, enabling six-point attachment to the target ion.
