2811.29.20.00 - Selenium dioxide

This category encompasses other inorganic oxygen compounds of nonmetals not specifically enumerated elsewhere in the subheading. It includes compounds that are not acids or oxides of metalloids like arsenic, nor specific common nonmetal oxides such as sulfur dioxide. The key characteristic is that these substances are inorganic, contain oxygen and a nonmetal, and do not fit into more precisely defined subheadings for such compounds.

This specific subheading, 2811.29.20.00, is dedicated to selenium dioxide. It distinguishes itself from the sibling category 2811.29.10.00, which covers arsenic trioxide, and 2811.29.30.00, which covers sulfur dioxide. While all are inorganic oxygen compounds of nonmetals, their chemical identity and specific uses differentiate them for tariff purposes. The residual category, 2811.29.50.00, serves as a catch-all for any other inorganic oxygen compounds of nonmetals that do not meet the criteria for the more specific subheadings.

As a leaf node, this HTS code for selenium dioxide has no further subdivisions. Classification within this heading relies on the precise chemical identity of the inorganic oxygen compound of a nonmetal. For selenium dioxide, its distinct chemical structure and properties are the primary factors for its classification here, ensuring it is not erroneously grouped with other nonmetal oxides.