# HS code 2809.10: Diphosphorus pentaoxide

> HS code 2809.10 covers diphosphorus pentaoxide. It sits in heading 28.09 (diphosphorus pentaoxide; phosphoric acid; polyphosphoric acids, whether or not chemically defined) in chapter 28 (inorganic chemicals; organic or inorganic compounds of precious metals, of rare-earth metals, of radioactive elements or of isotopes). Other goods of heading 28.09 are classified under 2809.20 (phosphoric acid or polyphosphoric acids). National tariff lines under 2809.10 are live on border.bot for the United States (1 line, also used by 1 other country).

Source: https://border.bot/hs-codes/280910
Last updated: 11 October 2026

[HS codes](https://border.bot/hs-codes) / [Chapter 28](https://border.bot/hs-codes/28) / [28.09](https://border.bot/hs-codes/2809) / [2809.10](https://border.bot/hs-codes/280910)

## Key facts

- HS code: 2809.10
- Covers: Diphosphorus pentaoxide
- Heading: [28.09: Diphosphorus pentaoxide; phosphoric acid; polyphosphoric acids, whether or not chemically defined](https://border.bot/hs-codes/2809)
- Chapter: [28: Inorganic chemicals; organic or inorganic compounds of precious metals, of rare-earth metals, of radioactive elements or of isotopes](https://border.bot/hs-codes/28)
- Edition: HS2022
- Duty in the United States: [See its 1 line](https://border.bot/countries/united-states/hs-codes/280910)

## What this code covers

HS code 2809.10 covers diphosphorus pentaoxide.

The legal text of the subheading is “Diphosphorus pentaoxide”, in HS2022.

## What it doesn’t cover

Other goods of heading 28.09 are classified under 2809.20 (phosphoric acid or polyphosphoric acids).

- [2809.20](https://border.bot/hs-codes/280920) Phosphoric acid and polyphosphoric acids

## How it is structured

2809.10 is a six-digit subheading. Its first two digits, 28, are the chapter; the first four, 2809, are heading 28.09; the last two, 10, identify the subheading within the heading.

Countries add their own digits after these six for their national tariff lines.

- Chapter 28: Inorganic chemicals; organic or inorganic compounds of precious metals, of rare-earth metals, of radioactive elements or of isotopes
- Heading 28.09: Diphosphorus pentaoxide; phosphoric acid; polyphosphoric acids, whether or not chemically defined
- Subheading 2809.10: Diphosphorus pentaoxide

## In other countries

National tariff lines under 2809.10 are live on border.bot for the United States (1 line, also used by 1 other country).

- [United States](https://border.bot/countries/united-states/hs-codes/280910): 1 line, used by 1 other country

- Previous subheading: [2808.00](https://border.bot/hs-codes/280800) Nitric acid; sulphonitric acids
- Next subheading: [2809.20](https://border.bot/hs-codes/280920) Phosphoric acid and polyphosphoric acids

## Frequently asked questions

### What does HS code 2809.10 cover?

HS code 2809.10 covers diphosphorus pentaoxide.

### Which heading and chapter is HS code 2809.10 in?

HS code 2809.10 is in heading 28.09 (diphosphorus pentaoxide; phosphoric acid; polyphosphoric acids, whether or not chemically defined) in chapter 28 (inorganic chemicals; organic or inorganic compounds of precious metals, of rare-earth metals, of radioactive elements or of isotopes).

### Where are goods of heading 28.09 classified when 2809.10 doesn’t fit?

Other goods of heading 28.09 are classified under 2809.20 (phosphoric acid or polyphosphoric acids).

### Which countries’ tariffs list national lines under HS code 2809.10?

National tariff lines under 2809.10 are live on border.bot for the United States (1 line, also used by 1 other country).

## Sources and updates

The Harmonized System legal text comes from border.bot release 2 (edition HS 2022), imported from a file, and has been live since 11 October 2026.

This page was last updated on 11 October 2026.

Guidance from published tariff data, not a binding ruling. For a decision customs must follow, apply to the destination’s customs authority for a binding tariff ruling.

Machine-readable: https://border.bot/hs-codes/280910.json