2836.99 - Other:

This HTS category, 2836.99, encompasses carbonates and related compounds that are not specifically listed under other headings within Chapter 28. It serves as a residual category for various inorganic carbonates not otherwise classified. The scope of this heading is broad, covering a range of metallic and non-metallic carbonates, as well as commercial ammonium carbonate and its related compounds.

Distinguishing this category from its siblings, 2836.91 (Lithium carbonates) and 2836.92 (Strontium carbonate), is crucial. While those codes are precisely defined for specific metal carbonates, 2836.99 is for all *other* carbonates, meaning it applies when the carbonate is not of lithium or strontium. This residual nature highlights the importance of checking more specific codes first before applying this general category.

The subcategories within 2836.99 further refine the classification of these "other" carbonates. They provide specific designations for cobalt carbonates, bismuth carbonate, commercial ammonium carbonate and other ammonium carbonates, and lead carbonates. The existence of these subcategories indicates that these specific compounds have distinct classification requirements. The final subcategory, 2836.99.50, serves as a further residual for any remaining carbonates not falling into the more specific sub-classifications, emphasizing a hierarchical approach to classification.