Ethylene Diamine Tetraacetic Acid Zinc Disodium (EDTA-ZnNa₂)

CAS No.: 14025-21-9

Molecular Formula: C₁₀H₁₂N₂Na₂O₈Zn

Molecular Weight: 399.59

Structural Formula:

Properties:

EDTA-ZnNa₂ is used as a trace element in agriculture.

Environmental Aspects:
Biodegradability: Difficult.
COD (Chemical Oxygen Demand) Value: 555 mg/g.

Specifications:

Usage:

EDTA-ZnNa₂ is a stable water-soluble metal chelate, and zinc exists in a chelated state. EDTA-ZnNa₂is used as a separating agent.. EDTA-ZnNa₂ is a kind of stable water-soluble metal chelate. EDTA-ZnNa₂ can chelate multivalent ferric ions. EDTA-ZnNa₂can be used for foliar fertilizers.

Packing and storage:

25kg woven bag. Stored in a cool, dry place, it must be packaged after opening.

Keywords:

EDTA-ZnNa₂; EDTA-Zn; EDTA Zinc Salt; EDTA

EDTA and Zn²⁺

1. What is the coordination number of Zn²⁺ when EDTA forms a complex with Zn²⁺?

EDTA is an amino carboxylic chelating agent with six coordinating atoms (two amine nitrogen and four carboxyl oxygen donating lone pair electrons). It can form 5-atom ring stable 1:1 chelates with metal ions. The coordination number of the central ion (Zn²⁺) is 6. Regular octahedral structure.

2. When EDTA titrates Zn²⁺, why should NH₃-NH₄Cl be added?

NH₃-NH₄Cl is added as a buffer to stabilize the pH of the solution.

Zn²⁺ was titrated with EDTA. The metal indicator is first added to the zinc solution. The metal indicator is first added to the zinc solution. Then, the zinc reacts with the indicator to form a complex, and the color changes. Metal indicators are generally weakly acidic, with high sensitivity and obvious color reaction. But at the same time, it also has a certain pH range. Beyond this range, the color change will not be obvious. And that complex is unstable and even has the possibility of failure.

In a complexometric titration, hydrogen ions are generally released. Therefore, as the reaction proceeds, the pH of the solution changes continuously.This seriously affects the color development of the indicator. Therefore, a certain amount of buffer solution should be added during titration to control the pH value of the solution in a certain range. Only in this way can the experimental phenomena be obvious and the results be accurate.