Phosphorous acid

  • Orthophosphorous acid
  • Phosphonic acid
  • Phosphorus trihydroxide
  • Trihydroxyphosphine
  • Dihydroxyphosphine oxide
Formula
H3PO3
Structure
Description
White crystals or chunks with a faint odor.

Registry Numbers and Inventories.
CAS
13598-36-2
EC (EINECS/ELINCS)
237-066-7
EC Index Number
015-157-00-0
EC Class
Harmful; Corrosive
R 22 35
S 26 36/37/39 45
RTECS
SZ6400000
RTECS class
Other
UN (DOT)
2834
Merck
12,7502
Beilstein/Gmelin
1619 (G)
Swiss Giftliste 1
G-8551
Canada DSL/NDSL
DSL
US TSCA
Listed
Austrailia AICS
Listed
New Zealand
Listed
Japan ENCS (MITI)
Listed
Korea ECL
Listed

Properties.
Formula
H3O3P
Formula mass
82.00
Melting point, °C
73
Decomposition point, °C
160 - 170
Density
1.651 g/cm3 (21 C)
Solubility in water
82 g/L (20 C)
Refractive index
1.4315 (76 C)
Heat of fusion
12.8 kJ/mol

Hazards and Protection.
Storage
Keep container closed when not in use. Store in a tightly closed container. Keep under a nitrogen blanket. Store in a cool, dry, well-ventilated area away from incompatible substances. Corrosives area.
Handling
Wash thoroughly after handling. Use with adequate ventilation. Minimize dust generation and accumulation. Do not get in eyes, on skin, or on clothing. Keep container tightly closed. Do not ingest or inhale. Use only in a chemical fume hood. Discard contaminated shoes.
Protection
Eyes: Wear appropriate protective eyeglasses or chemical safety goggles as described by OSHA's eye and face protection regulations in 29 CFR 1910.133 or European Standard EN166. Skin: Wear appropriate protective gloves to prevent skin exposure. Clothing: Wear appropriate protective clothing to prevent skin exposure.
Respirators
Follow the OSHA respirator regulations found in 29CFR 1910.134 or European Standard EN 149. Always use a NIOSH or European Standard EN 149 approved respirator when necessary.
Small spills/leaks
Vacuum or sweep up material and place into a suitable disposal container. Clean up spills immediately, using the appropriate protective equipment. Avoid generating dusty conditions. Provide ventilation.
Stability
Has not been fully evaluated.
Incompatibilities
Strong oxidizing agents.
Decomposition
Phosphine, oxides of phosphorus.

Fire.
Fire fighting
Wear a self-contained breathing apparatus in pressure-demand, MSHA/NIOSH (approved or equivalent), and full protective gear. Combustion generates toxic fumes. During a fire, irritating and highly toxic gases may be generated by thermal decomposition or combustion. Extinguishing media: Use dry chemical to fight fire.
Fire potential
Non-combustible, substance itself does not burn but may decompose upon heating to produce corrosive and/or toxic fumes.
Hazards
Some are oxidizers and may ignite combustibles (wood, paper, oil, clothing, etc.). Contact with metals may evolve flammable hydrogen gas. Containers may explode when heated.
Combustion products
Non-combustible, substance itself does not burn but may decompose upon heating to produce corrosive and/or toxic fumes.

Health.
Poison_Class
2
Exposure effects
   Ingestion
May cause severe and permanent damage to the digestive tract. Causes gastrointestinal tract burns. May be harmful if swallowed.
   Inhalation
May cause severe irritation of the respiratory tract with sore throat, coughing, shortness of breath and delayed lung edema. Causes chemical burns to the respiratory tract.
   Skin
Causes skin burns.
   Eyes
Causes eye burns.

First aid
 
   Ingestion
Do NOT induce vomiting. If victim is conscious and alert, give 2-4 cupfuls of milk or water. Never give anything by mouth to an unconscious person. Get medical aid immediately.
   Inhalation
Get medical aid immediately. Remove from exposure to fresh air immediately. If breathing is difficult, give oxygen. DO NOT use mouth-to-mouth respiration. If breathing has ceased apply artificial respiration using oxygen and a suitable mechanical device such as a bag and a mask.
   Skin
Get medical aid immediately. Immediately flush skin with plenty of soap and water for at least 15 minutes while removing contaminated clothing and shoes. Wash clothing before reuse. Destroy contaminated shoes.
   Eyes
Immediately flush eyes with plenty of water for at least 15 minutes, occasionally lifting the upper and lower eyelids. Get medical aid immediately. Do NOT allow victim to rub or keep eyes closed. Extensive irrigation is required (at least 30 minutes).

Transport.
UN number
2834
Response guide
Hazard class
8
Packing Group
III
 
Std. Transport #
4931451