Chromic acid

  • Chromic (VI) acid
  • Chromium hydroxide oxide
Formula
H2CrO4
Structure
Description
Chromic acid, solid is a dark purplish red solid.
Uses
Chromium plating intermediate, medicine (caustic), process engraving, anodizing, ceramic glazes, colored glass, metal cleaning, inks, tanning, paints.

Registry Numbers and Inventories.
CAS
7738-94-5
EC (EINECS/ELINCS)
231-801-5
RTECS
GB2450000
RTECS class
Mutagen
UN (DOT)
1463
Beilstein/Gmelin
15491 (G)
RCRA
D007
EPA OPP
21101
Canada DSL/NDSL
DSL
US TSCA
Listed
Austrailia AICS
Listed
New Zealand
Listed
Korea ECL
Listed

Properties.
Formula
CrH2O4
Formula mass
118.02
Melting point, °C
196
Sublimation point, °C
110 - 130 (16 C)
Decomposition point, °C
210
Density
2.70 g/cm3 (20 C)
Solubility in water
Very soluble
Dielectric constant
6.95 (20 C)
Thermal expansion
0.00017/K (23 C)

Hazards and Protection.
Storage
Isolate. Protect from physical damage. Separate from combustible, organic or other readily oxidizable materials. Protect from moisture. Avoid storage on wooden floors.
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
Approved respirators, vaseline for lubrication of nostrils, rubberized outer wear and safety goggles are required. Rubber is poor and pva not recommended for gloves (cheea3 0001); white creams should not be relied upon. They can be used to cover unprotected area. Do not use organic clothes as part of outer wear, must be rubberized fabric.
Respirators
Wear positive pressure self-contained breathing apparatus (SCBA).
Small spills/leaks
Keep sparks, flames, and other sources of ignition away. Keep material out of water sources and sewers. Neutralize spilled material with crushed limestone, soda ash, or lime. Land spill: Dig a pit, pond, lagoon, holding area to contain liquid or solid material. Cover solids with a plastic sheet to prevent dissolving in rain or fire fighting water. Neutralize with agricultural lime (CaO), crushed limestone (CaCO3) or sodium bicarbonate (NaHCO3). Water spill: Neutralize with agricultural lime (CaO), crushed limestone (CaCO3), or sodium bicarbonate (NaHCO3). Use mechanical dredges or lifts to remove immobilized masses of pollutants and precipitates.
Stability
Normally stable. Reactive under extreme conditions. Containers may explode when involved in fire. Violent reaction with powerful reducers.
Incompatibilities
Keep away from acetic acid, acetic anhydride, acetone, alcohols, alkali metals.
Decomposition
Irritating and toxic fumes.

Fire.
Fire fighting
Flood with water. Apply water from as far a distance as possible.
Fire potential
Will ignite on contact with acetic acid and alcohol. Hazard may be quite evident; can ignite organic matter on contact.
Hazards
Containers may explode
Combustion products
Fire may produce irritating, corrosive and/or toxic gases.
Health
3
 
Flammability
0
 
 
Reactivity
1
 
 
Special
O

Health.
Exposure limit(s)
TLV (as Cr): ppm; 0.05 mg/m3 (ACGIH 1993-1994).
Carcinogin
G-A1, I-1, N-1, CP65
Exposure effects
The toxological properties of this substance have not been fully investigated.
   Ingestion
Causes irritation and burns.
   Inhalation
Inhalation of dust is toxic. Causes irritation and burns. Severe over exposure may result in death.
   Skin
May cause severe burns.
   Eyes
See Skin.

First aid
 
   Ingestion
Call a physician; do NOT induce vomiting.
   Inhalation
Move patient to fresh air. Monitor for respiratory distress. If cough or difficulty breathing develops, evaluate for respiratory tract irritation, bronchitis, or pneumonitis. Administer oxygen and assist ventilation as required. Treat bronchospasm with beta2 agonist and corticosteroid aerosols.
   Skin
Immediately dilute with 4 to 8 ounces (120 to 240 ml) of milk or water (not to exceed 4 ounces/120 ml in a child). Do not induce vomiting. Administer ascorbic acid (1 g per 0.135 G of elemental chromium). Neutralization is not indicated. Cautious gastric lavage with a small flexible tube is suggested by some authors.
   Eyes
Wash eyes thoroughly for at least 15 min.; flush contacted skin areas with water; remove contaminated clothing and wash before reuse.

Transport.
UN number
1463
Response guide
Hazard class
5.1
Packing Group
II
 
USCG CHRIS Code
CMA
 
Std. Transport #
4918511