Hydrogen iodide

  • Hydrogen iodide, anhydrous
Formula
HI
Structure
Description
A colorless to yellow/brown gas with an acrid odor.
Uses
Reducing agent, manufacture of inorganic iodides, pharmaceuticals, disinfectants. The 57% acid is also used for analytical purposes, such as methoxyl determinations.

Registry Numbers and Inventories.
CAS
10034-85-2
EC (EINECS/ELINCS)
233-109-9
EC Index Number
053-002-00-9
EC Class
Corrosive
S 9 26 36/37/39 45
RTECS
MW3760000
UN (DOT)
1787
Merck
13,4797
Beilstein/Gmelin
814 (G)
EPA OPP
46912
Swiss Giftliste 1
G-1728
Canada DSL/NDSL
DSL
US TSCA
Listed
Austrailia AICS
Listed
New Zealand
Listed
Japan ENCS (MITI)
Listed
Korea ECL
Listed

Properties.
Formula
HI
Formula mass
127.91
Melting point, °C
-51
Boiling point, °C
127
Vapor pressure, mmHg
3400 (6 C)
Density
1.53 g/cm3
Solubility in water
Very soluble
Viscosity
0.01321 P (-39 C)
Surface tension
28.6 erg/cm2 (-46 C)
Refractive index
1.466 (16 C)
Dipole moment
0.42 D
Dielectric constant
1.002 (22 C)
Heat of fusion
2.6 kJ/mol
Heat of vaporization
20.0 kJ/mol

Hazards and Protection.
Storage
Keep in a cool, dry, dark location in a tightly sealed container or cylinder. Keep away from incompatible materials, ignition sources and untrained individuals. Secure and label area. Protect containers/cylinders from physical damage.
Handling
All chemicals should be considered hazardous. Avoid direct physical contact. Use appropriate, approved safety equipment. Untrained individuals should not handle this chemical or its container. Handling should occur in a chemical fume hood.
Protection
Wear appropriate chemical protective clothing.
Respirators
Wear positive pressure self-contained breathing apparatus.
Small spills/leaks
Keep material out of water sources and sewers. Attempt to stop leak if without undue personnel hazard. Use water spray to knock-down vapors. Do not use water on material itself.
Stability
Decomposes by light; fumes in moist air.
Incompatibilities
Reacts rapidly and exothermically with bases Reacts with active metals in the presence of moisture, including such structural metals as aluminum and iron, to release hydrogen, a flammable gas Reacts with cyanide compounds to release gaseous hydrogen cyanide Reacts with oxidizing agents to give iodine (when passed through fuming nitric acid, each bubble produces iodine attended by a flash of red flame.
Decomposition
When heated to decomposition, it emits highly toxic fumes of hydrogen iodide.

Fire.
Fire fighting
Extinguish fire using agent suitable for type of surrounding fire. (Material itself does not burn or burns with difficulty.) Cool all affected containers with flooding quantities of water. Do not apply water to point of leak in tank car or container. Apply water from as far a distance as possible. Do not use water on material itself. If large quantities of combustibles are involved, use water in flooding quantities as spray and fog. Use water spray to knock-down vapors.
Fire potential
May burn but does not ignite readily.
Hazards
Vapors from liquefied gas are initially heavier than air and spread along ground. Some of these materials may react violently with water. Containers may explode when heated. Ruptured cylinders may rocket.
Combustion products
Non-combustible, substance itself does not burn but may decompose upon heating to produce corrosive and/or toxic fumes.
Health
3
 
Flammability
0
 
 
Reactivity
0
 

Health.
Poison_Class
2
Exposure effects
Abnormal neuropsychologic function has been reported following hydrochloric acid exposure from a leaking tanker truck. Cretinism and goiter have been reported in children whose mothers were taking iodides.
   Ingestion
Ingestion of acids may result in burns, gastrointestinal bleeding, gastritis, perforations, dilation, edema, necrosis, vomiting, stenosis, fistula, and duodenal/jejunal injury.
   Inhalation
Inhalation may produce dyspnea, pleuritic chest pain, upper airway edema, pulmonary edema, hypoxemia, bronchospasm, pneumonitis, and persistent pulmonary function abnormalities. Airway hyperreactivity has also been reported.
   Skin
Contact with molten substance may cause severe burns to skin and eyes. See Inhalation.
   Eyes
A metallic taste, increased salivary and bronchial secretions may be noted.

First aid
 
   Ingestion
Seek medical assistance.
   Inhalation
Move victim to fresh air. Apply artificial respiration if victim is not breathing. Do not use mouth-to-mouth method if victim ingested or inhaled the substance; induce artificial respiration with the aid of a pocket mask equipped with a one-way valve or other proper respiratory medical device. Administer oxygen if breathing is difficult.
   Skin
Remove contaminated clothing, wash exposed area with copious amounts of water. A physician should examine the area if irritation or pain persists.
   Eyes
Immediately flush with running water for at least 20 minutes.

Transport.
UN number
1787
Response guide
Hazard class
8
Packing Group
II; III
 
USCG CHRIS Code
HIA
 
Std. Transport #
4920348