2833.40 - Peroxosulfates (persulfates):

This HTS category, 2833.40, encompasses peroxosulfates, also known as persulfates. These are salts derived from peroxomonosulfuric acid and peroxodisulfuric acid. Industrially significant peroxosulfates include ammonium, potassium, and sodium persulfates, which are characterized by the presence of the peroxodisulfate ion (S₂O₈²⁻). Their strong oxidizing properties lend them to a variety of applications, such as initiators for polymerization, bleaching agents, and etchants in electronics manufacturing.

Distinguishing 2833.40 from its siblings is crucial for accurate classification. While the parent category covers general sulfates, alums, and peroxosulfates, this specific subheading isolates the peroxosulfates. It excludes simple sulfates (2833.21 through 2833.29), which lack the peroxide linkage, and alums (2833.30.00.00), which are double sulfates of aluminum with another monovalent metal or ammonium. Therefore, the presence of the active oxygen in the peroxodisulfate anion is the defining characteristic of goods within this classification.

The subcategories within 2833.40 further refine the classification based on the cation present. The subcategory "2833.40.20.00: Of sodium" specifically covers sodium peroxosulfate (sodium persulfate). The remaining peroxosulfates, such as ammonium peroxosulfate and potassium peroxosulfate, fall under the broader category of "2833.40.60: Other." This division allows for precise tariff reporting based on the chemical composition of the imported or exported peroxosulfate.