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Phosphorus trioxide

CAS No.1314-24-5
Chemical Name:Phosphorus trioxide
CBNumber:CB2852146
Molecular Formula:H4O5P2
Formula Weight:145.976282
MOL File:1314-24-5.mol

Phosphorus trioxide Property

Melting point 23.8°
Boiling point bp 173.1° in nitrogen atm
Density d421 2.135
solubility reacts with H2O
form colorless monoclinic crystals or liquid
color colorless monoclinic crystals, crystalline or liquid
Water Solubility slowly forms H3PO3 in cold H2O; reacts violently in hot H2O forming red P, PH3, and H3PO4 [MER06]
crystal system Monoclinic
Space group P21/m
Lattice constant
a/nm b/nm c/nm α/o β/o γ/o V/nm3
0.643 0.7887 0.6812 90 106.01 90 0.3321
FDA UNII 0LTR52K7HK
EPA Substance Registry System Phosphorus trioxide (1314-24-5)

a/nm	b/nm	c/nm	α/o	β/o	γ/o	V/nm3
0.643	0.7887	0.6812	90	106.01	90	0.3321

Safety

RIDADR :2578
HazardClass :8
PackingGroup :III

Hazard and Precautionary Statements (GHS)

Symbol(GHS)
Signal word
Hazard statements
Precautionary statements

Phosphorus trioxide Chemical Properties,Usage,Production

Chemical Properties transparent crystal(s); monoclinic or colorless liquid; disproportionates to red P and P2O4if heated above 210°C [MER06]
General Description White crystalline solid or a liquid (melting point 24°C). Density 2.14 g / cm3. Toxic and corrosive. May severely irritate skin and eyes. Used to make other chemicals.
Air & Water Reactions Fumes in air. Reacts slowly with cold water to give phosphorous acid. Reacts vigorously with hot water to generate red phosphorus, phosphine (highly toxic and flammable) and phosphoric acid [Merck 11th ed. 1989].
Reactivity Profile Phosphorus trioxide reacts exothermically with bases. Melted Phosphorus trioxide readily ignites in air. Instantly ignites with a flame of almost blinding brilliance when thrown into oxygen at 50-60°C [J. Am. Chem. Soc. 125:347. 1924]. Incompatible with ammonia, disulfur dichloride, halogens, oxygen, phosphorus pentachloride, sulfur, sulfuric acid, water [Bretherick, 5th ed., 1995, p. 1778].
Health Hazard TOXIC; inhalation, ingestion or contact (skin, eyes) with vapors, dusts or substance may cause severe injury, burns or death. Reaction with water or moist air will release toxic, corrosive or flammable gases. Reaction with water may generate much heat that will increase the concentration of fumes in the air. Fire will produce irritating, corrosive and/or toxic gases. Runoff from fire control or dilution water may be corrosive and/or toxic and cause pollution.
Fire Hazard Non-combustible, substance itself does not burn but may decompose upon heating to produce corrosive and/or toxic fumes. Vapors may accumulate in confined areas (basement, tanks, hopper/tank cars etc.). Substance will react with water (some violently), releasing corrosive and/or toxic gases and runoff. Contact with metals may evolve flammable hydrogen gas. Containers may explode when heated or if contaminated with water.