Headings 2816 through 2824 each cover specific metals (magnesium, zinc, aluminum, chromium, manganese, iron, cobalt, titanium, and lead). If the metal oxide in question is not one of those, it will generally fall under 2825, which covers all remaining inorganic bases and metal oxides NESOI. Always check the specific subheadings within 2825 — such as 282520 for lithium, 282530 for vanadium, or 282540 for nickel — before defaulting to the NESOI subheading 282590.

Battery-grade lithium hydroxide monohydrate (LiOH·H₂O) classifies under 282520 along with technical and industrial grades. The tariff line does not distinguish by purity grade, but battery manufacturers specify tight purity thresholds (typically 56.5% LiOH minimum, low impurity ceilings) that are commercial rather than tariff distinctions. Importers should ensure the certificate of analysis matches both the tariff declaration and the buyer's specification.