HazMat Tool — substance information

Phosphorus pentoxide

HMT May 2026

UN / ID: UN 1807
Hazard class: 8
Packing group: II
ERG guide: ERG 137
Special provisions: SP A7, SP IB8, SP IP2, SP IP4, SP N34, SP T3, SP TP33
Source: 49 CFR §172 (2026/05)

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Phosphorus pentoxide

Phosphorus pentoxide is a chemical compound with molecular formula P4O10 (with its common name derived from its empirical formula, P2O5). This white crystalline solid is the anhydride of phosphoric acid. It is a powerful desiccant and dehydrating agent. Wikipedia

Substance Data

Source: PubChem (HSDB, 15.12.2019)

CAS-Number

1314-56-3

Flash Point

n/a

Boiling Point

n/a

Emergency Response Guide No. 137

Hazardous Materials Table

Source: 49 CFR §172 (2026/05)

(3) Hazard Class

8
Corrosive liquids

(4) Identification number

UN 1807

(5) Packing Group

(6) Labels

(7) Special Provisions (§172.102)

×Note:
Special provisions may be very complex. The extracts are taken from 49 CFR §172.102. Please be careful with the information, as necessary, additional conditions may be applied that are not written here. Please check the original source and report bugs.

Steel packagings must be corrosion-resistant or have protection against corrosion.

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IB8

Authorized IBCs: Metal (11A, 11B, 11N, 21A, 21B, 21N, 31A, 31B and 31N); Rigid plastics (11H1, 11H2, 21H1, 21H2, 31H1 and 31H2 ); Composite (11HZ1, 11HZ2, 21HZ1, 21HZ2 and 31HZ1); Fiberboard (11G); Wooden (11C, 11D and 11F); Flexible (13H1, 13H2, 13H3, 13H4, 13H5, 13L1, 13L2, 13L3, 13L4, 13M1 or 13M2).

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IP2

When IBCs other than metal or rigid plastics IBCs are used, they must be offered for transportation in a closed freight container or a closed transport vehicle.

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IP4

Flexible, fiberboard or wooden IBCs must be sift-proof and water-resistant or be fitted with a sift-proof and water-resistant liner.

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N34

Aluminum construction materials are not authorized for any part of a packaging which is normally in contact with the hazardous material.

Browse special provision N34

Minimum test pressure (bar)	2.65
Minimum shell thickness	§ 178.274(d)(2)
Pressure-relief requirements	Normal
Bottom opening requirements	§ 178.275(d)(2)

Browse special provision T3

TP33

The portable tank instruction assigned for this substance applies for granular and powdered solids and for solids which are filled and discharged at temperatures above their melting point which are cooled and transported as a solid mass. Solid substances transported or offered for transport above their melting point are authorized for transportation in portable tanks conforming to the provisions of portable tank instruction T4 for solid substances of packing group III or T7 for solid substances of packing group II, unless a tank with more stringent requirements for minimum shell thickness, maximum allowable working pressure, pressure-relief devices or bottom outlets are assigned in which case the more stringent tank instruction and special provisions shall apply. Filling limits must be in accordance with portable tank special provision TP3. Solids meeting the definition of an elevated temperature material must be transported in accordance with the applicable requirements of this subchapter.

Browse special provision TP33

(8) Packing Authorizations (§173.***)

(8A) Exceptions	154	see 49 CFR §173.154
(8B) Non-bulk	212	see 49 CFR §173.212
(8C) Bulk	240	see 49 CFR §173.240

(9) Quantity Limits

(9A) Passenger aircraft/rail	15 kg
(9B) Cargo aircraft only	50 kg

(10) Vessel stowage

(10A) Location

Stowage category “A” means the material may be stowed “on deck” or “under deck” on a cargo vessel or on a passenger vessel.

Source: 49 CFR §172.101(k)

(10B) Other

53	see 49 CFR §176.84
58	see 49 CFR §176.84

Source: 49 CFR §176.84

Segregation chart for load, transport, and storage

This chart shows whether loading, transport, or storage with other hazard classes is permitted, prohibited, or restricted. Based on 49 CFR §177.848.

Note: In this segregation and separation chart are HazMat of hazard class 8 considered depending if there are liquid. Currently HazMat Tool is not able to to check if a HazMat is liquid or not. Therefore it is assumed as liquid. See PHMSA Interpretation #09-0252.

Hazard class	8	7	6.1	5.2	5.1	4.3	4.2	4.1	3	2.3B	2.3A	2.2	2.1	1.6	1.5	1.4	1.3	1.1/1.2
1.1/1.2
1.3
1.4
1.5
1.6
2.1
2.2
2.3A
2.3B
3
4.1
4.2
4.3
5.1
5.2
6.1
7
8

	Must not be loaded, transported, or stored together in the same vehicle or facility.
	May be loaded, transported, or stored together.
	May be loaded, transported, or stored together only with restrictions.

Similar substances

UN / ID	Proper shipping name	Hazard class
UN 1381	Phosphorus, white dry or Phosphorus, white, under water or Phosphorus white, in solution or Phosphorus, yellow dry or Phosphorus, yellow, under water or Phosphorus, yellow, in solution	4.2
NA 1955	Organic phosphate, mixed with compressed gas or Organic phosphate compound, mixed with compressed gas or Organic phosphorus compound, mixed with compressed gas	2.3
UN 3017	Organophosphorus pesticides, liquid, toxic, flammable, flash point not less than 23 degrees C	6.1
UN 2784	Organophosphorus pesticides, liquid, flammable, toxic, flash point less than 23 degrees C	3
UN 0243	Ammunition, incendiary, white phosphorus, with burster, expelling charge or propelling charge	1.2H
UN 0244	Ammunition, incendiary, white phosphorus, with burster, expelling charge or propelling charge	1.3H
	Ammunition, smoke (water-activated contrivances), without white phosphorus or phosphides, with burster, expelling charge or propelling charge, see Contrivances, water-activated, etc. (UN 0249)
UN 0245	Ammunition smoke, white phosphorus with burster, expelling charge, or propelling charge	1.2H
UN 0246	Ammunition, smoke, white phosphorus with burster, expelling charge, or propelling charge	1.3H
	Ammunition, smoke (water-activated contrivances), white phosphorus, with burster, expelling charge or propelling charge, see Contrivances, water-activated, etc. (UN 0248)
	Phosphorus (white or red) and a chlorate, mixtures of	Forbidden
UN 1340	Phosphorus pentasulfide, free from yellow or white phosphorus	4.3
UN 1339	Phosphorus heptasulfide, free from yellow or white phosphorus	4.1
UN 1341	Phosphorus sesquisulfide, free from yellow or white phosphorus	4.1
UN 1343	Phosphorus trisulfide, free from yellow or white phosphorus	4.1