Substance profile
Phosphorus pentoxide
Phosphorus pentoxide is a chemical substance with the molecular formula O5P2.
01 · Identification
What Phosphorus pentoxide is
Phosphorus pentoxide is a chemical substance with the molecular formula O5P2. Its molecular formula is O5P2 and its molecular weight is 141.94 g/mol.
Under the GHS it carries the signal word Danger.
02 · Identifiers
Phosphorus pentoxide identifiers and molecular data
Phosphorus pentoxide CAS number and EC number
Phosphorus pentoxide molecular formula and molecular weight
03 · GHS classification
Phosphorus pentoxide hazard classification
Harmonised classification under CLP Annex VI. This is the legally binding classification in the EU; other jurisdictions may differ.
Phosphorus pentoxide pictograms and signal word
Phosphorus pentoxide hazard class and category
| Hazard class | Category | From code | Pictogram |
|---|---|---|---|
| Skin corrosion/irritation GHS chapter 3.2 | Category 1A or 1B or 1C | H314 | GHS05 |
Where two values are shown with “or”, the hazard statement is shared by more than one category or by more than one class, and the code alone does not say which. H272, for example, belongs to oxidising liquids and to oxidising solids — the physical state decides. The binding answer for a specific entry is in the CLP Annex VI table itself.
Phosphorus pentoxide hazard statements (H-codes)
| Code | Hazard statement |
|---|---|
| H314 | Causes severe skin burns and eye damage. |
This page lists only the codes assigned to Phosphorus pentoxide. The full reference lives on the hazard statements hub, the precautionary statements hub and the GHS pictograms hub.
Safety Data Sheet
Getting an SDS for Phosphorus pentoxide
A Safety Data Sheet is written for a product, not for a substance: the supplier of the grade you actually buy issues it, so two suppliers of Phosphorus pentoxide issue two different sheets. That is why there is no single authoritative SDS for a substance to download — what there is, is the job of collecting the sheets for the products you hold and keeping them current as suppliers revise them.
04 · Precautionary statements
Phosphorus pentoxide precautionary statements
CLP Annex VI assigns 5 precautionary statements to Phosphorus pentoxide. They are grouped the way a label groups them: what to do before handling, what to do when something has already happened, how to store it and how to dispose of it.
Prevention
What to do before and during handling so the hazard never happens.
Response
What to do once exposure, spillage or fire has already happened.
Reading the notation. … is a blank the supplier fills in — not a truncated sentence.· [square brackets] mark a part printed only when it applies.
05 · Names in the regulation
Phosphorus pentoxide name in 23 EU languages
CLP Annex VI Part 3 is published in every language edition of the regulation, and the identification column is written out in each of them. Nothing below is translated by us: each line is the name as that edition prints it. Under Art. 18(2) the substance name from Annex VI is a lawful product identifier, so this is the wording to put on a label going to that market — and where the cell lists several designations, any one of them qualifies.
| Language | Name in CLP Annex VI Part 3 |
|---|---|
| Bulgarian български | фосфорен пентаоксид |
| Spanish español | Pentóxido de fósforo |
| Czech čeština | oxid fosforečný |
| Danish dansk | phosphorpentaoxid |
| German Deutsch | Phosphorpentoxid |
| Estonian eesti | fosforpentoksiid |
| Greek ελληνικά | πεντοξείδιο του φωσφόρου |
| English English | phosphorus pentoxide |
| French français | pentoxyde de phosphore |
| Croatian hrvatski | fosforov pentoksid |
| Italian italiano | anidride fosforica |
| Latvian latviešu | fosfora pentoksīds |
| Lithuanian lietuvių | fosforo pentoksidas |
| Hungarian magyar | foszfor-pentoxid |
| Maltese Malti | pentossidu tal-fosforu |
| Dutch Nederlands | fosforpentoxide |
| Polish polski | dekatlenek tetrafosforu pentatlenek difosforubezwodnik kwasu fosforowego(V)bezwodnik kwasu ortofosforowego(V) |
| Portuguese português | pentóxido de fósforo |
| Romanian română | pentoxid fosforic |
| Slovak slovenčina | oxid fosforečný |
| Slovenian slovenščina | fosforjev pentoksid |
| Finnish suomi | fosforipentoksidi |
| Swedish svenska | fosforpentoxid |
All 23 language editions of Annex VI carry this entry. Irish is the twenty-fourth official EU language and has no line here for a different reason: no consolidated CLP text has ever been published in Irish, so there is no Irish edition of Annex VI to quote a name from. Source: consolidated CLP, CELEX 02008R1272, language editions. © European Union, https://eur-lex.europa.eu — only the electronic Official Journal of the European Union is authentic.
06 · Label elements
Phosphorus pentoxide GHS label elements
Everything CLP Annex VI fixes for Phosphorus pentoxide, laid out the way it appears on a label. The greyed lines are the parts only the supplier can fill in.
Danger
Phosphorus pentoxide
- Causes severe skin burns and eye damage.
- Do not breathe dust/fume/gas/mist/vapours/spray.
- Wear protective gloves/protective clothing/eye protection/face protection/hearing protection/…
- IF SWALLOWED:
- Immediately call a POISON CENTER/doctor/…
- Do NOT induce vomiting.
Supplier name, address and telephone number· Product identifier·Nominal quantity
Need this as an actual label? Open Phosphorus pentoxide in the GHS label constructor →
07 · Transport
Phosphorus pentoxide UN number and transport classification
Transport classification is a separate system from the GHS classification above. It decides how a package is marked and how a load may be carried; it does not follow from the workplace label, and the workplace label does not follow from it. The entries below are linked by CAS number, never by name.
Phosphorus pentoxide under UN 1807 — shipping name, class and packing group
Europe · ADR 2025, Table A
| Proper shipping name (3.1.2) | Class | Classification code | PG | Labels (column 5) |
|---|---|---|---|---|
| PHOSPHORUS PENTOXIDE | 8 | C2 | II | |
Source: ADR 2025, Table A of Chapter 3.2 · ECE/TRANS/352 Vol. I (UNECE). Class 8 is “Corrosive substances” (ADR 2.1.1.1).
United States · 49 CFR 172.101 Hazardous Materials Table
| Proper shipping name (column 2) | Class or division | PG | Labels (column 6) |
|---|---|---|---|
| Phosphorus pentoxide | 8 | II | |
Source: 49 CFR 172.101 Hazardous Materials Table · eCFR, revision 2026-08-03. Class 8 is “Corrosive material” (49 CFR 173.2).
08 · Questions
Phosphorus pentoxide — frequently asked questions
What is the CAS number of Phosphorus pentoxide?
The CAS number of Phosphorus pentoxide is 1314-56-3. Its EC number is 215-236-1.
What is the chemical formula of Phosphorus pentoxide?
The molecular formula of Phosphorus pentoxide is O5P2 and its molecular weight is 141.94 g/mol.
What does a Phosphorus pentoxide label have to show?
Under CLP Annex VI the label for Phosphorus pentoxide carries the pictogram Corrosion and the signal word is Danger.
Is Phosphorus pentoxide flammable?
CLP Annex VI assigns Phosphorus pentoxide no flammability hazard class. That is not a statement that it cannot burn: the harmonised list only records the hazards that were assessed for it.
Is Phosphorus pentoxide a carcinogen?
CLP Annex VI records no harmonised carcinogenicity classification for Phosphorus pentoxide. Annex VI is a list of agreed classifications, not a list of substances found safe, so this is an absence of a classification rather than a clean bill of health.
Nearby
Substances next to Phosphorus pentoxide
Keep going: substances starting with P, or search the whole database by name, CAS number, pictogram or signal word.