Hydrogen, gas

Formula
H2
Structure
Description
A colorless, odorless gas. Shipped as a compressed gas.
Uses
Oxyhydrogen flame is used in processing of quartz, in prodn of several metals which resist fusion, such as molybdenum, bismuth.

Registry Numbers and Inventories.
CAS
1333-74-0
EC (EINECS/ELINCS)
215-605-7
EC Index Number
001-001-00-9
EC Class
Extremely flammable
RTECS
MW8900000
RTECS class
Other
UN (DOT)
1966
Merck
12,4833
Beilstein/Gmelin
3 (G)
Swiss Giftliste 1
G-6842
Canada DSL/NDSL
DSL
US TSCA
Listed
Austrailia AICS
Listed
New Zealand
Listed
Korea ECL
Listed

Properties.
Formula
H2
Formula mass
2.01
Melting point, °C
-258.9
Boiling point, °C
-252.8
Vapor density (air=1)
0.07
Critical temperature
-239.9
Critical pressure
12.8
Density
0.071 g/cm3 (20 C)
Solubility in water
1.7 mg/L (20 C)
Viscosity
8.6E-5 P (0 C)
Surface tension
2.438 erg/cm2 (-254.5 C)
Dielectric constant
1.00026 (0 C)
Thermal expansion
0.00366/K (20 C)
Heat of fusion
0.13 kJ/mol
Heat of vaporization
0.90 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. Grounding and bonding of containers is required.
A B1
Handling
Containers of this material may be hazardous when emptied. Since emptied containers retain product residues (vapor, liquid, and/or solid), all hazard precautions given in the data sheet must be observed.
Protection
Wear appropriate protective gloves, clothing and goggles. Always wear thermal protective clothing when handling refrigerated/cryogenic liquids.
Respirators
For Unknown Concentrations or Immediately Dangerous to Life or Health - Any supplied-air respirator with full facepiece and operated in a pressure-demand or other positive-pressure mode in combination with a separate escape supply. Any self-contained breathing apparatus with a full facepiece.
Small spills/leaks
Keep sparks, flames, and other sources of ignition away. 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
Stable at normal temperature and pressures.
Incompatibilities
Reacts violently with air, oxygen, chlorine, fluorine, strong oxidizers causing fire and explosion hazard. Metal catalysts, such as platinum and nickel, greatly enhance these reactions.
Decomposition
Heating may cause violent combustion or explosion.

Fire.
Flash Point,°C
-18
Autoignition, °C
500-571
Upper exp. limit, %
76
Lower exp. limit, %
4
Fire fighting
Do not extinguish fire unless flow can be stopped. Use water in flooding quantities as fog. Cool all affected containers with flooding quantities of water. Apply water from as far a distance as possible. Do not use water on material itself.
Fire potential
Severe fire hazard. Severe explosion hazard. Vapor/air mixtures are explosive. May ignite spontaneously.
Hazards
Pressurized containers may rupture or explode if exposed to sufficient heat. Electrostatic discharges may be generated by flow or agitation resulting in ignition or explosion.
Combustion products
Water vapor.
Health
3
 
Flammability
4
 
 
Reactivity
0
 

Health.
Poison_Class
-
Exposure effects
Rapid breathing and rapid heart rate are common. In severe cases abnormally low blood pressure, apnea, and cardiac arrest develop. Various disturbances including headache, dizziness, mood disturbances, numbness of the extremities, sleepiness, mental confusion, poor judgement and coordination, and memory loss may occur. Prolonged or severe hypoxia results in unconsciousness. Prolonged asphyxia may produce CNS injury. Hemiparesis has been reported with volatile substance abuse. Cerebral edema with brainstem herniation may occur. Seizures have been reported following intentional inhalation.
   Ingestion
Unlikely route of exposure. Material is a gas at room temperature and atmospheric pressure and is essentially nontoxic.
   Inhalation
Simple asphyxiant. Inhalation of high concentrationss of hydrogen may cause dizziness, headache, possible nausea and eventual unconsciousness.
   Skin
None.
   Eyes
None.

First aid
 
   Ingestion
Seek medical assistance.
   Inhalation
If victim is unconscious (due to oxygen deficiency), move him to fresh air and apply resuscitation methods; call physician.
   Skin
Rewarming and a variety of topical treatments are indicated for frostbite injury. See main section for more information.
   Eyes
Treat for frostbite.

Transport.
UN number
1966
Response guide
Hazard class
2.1
USCG CHRIS Code
HXX
 
Std. Transport #
4905745