Chromium chromate

  • Chromic acid, chromium salt
Formula
Cr2(CrO4)3
Description
Brownish-red powder.
Uses
Corrosion inhibitor for zinc, cadmium, and magnesium.

Registry Numbers and Inventories.
CAS
41261-95-4
Beilstein/Gmelin
105756 (G)
RCRA
D007

Properties.
Formula
Cr5O12
Formula mass
451.97
Solubility in water
Insoluble

Hazards and Protection.
Storage
Storage location should be close to laboratory where it is to be used, so that only small amounts need to be transported. Carcinogens should be kept in only one section of storage area, explosion-proof refrigerator or freezer as required. The area should be appropriately labeled. An inventory should be kept showing the quantity of carcinogen and date it was acquired. Facilities for dispensing should be contiguous to storage area.
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 clothing to prevent any reasonable probability of skin contact. Wear eye protection to prevent any possibility of eye contact.
Respirators
At concentrations above the NIOSH rel, or where there is no rel, at any detectable concentration: respirator class(es): any self-contained breathing apparatus that has a full facepiece and is operated in a pressure-demand or other positive pressure-mode. Any supplied-air respirator that has a full facepiece and is operated in a pressure-demand or other positive-pressure mode in combination with an auxiliary self-contained breathing apparatus operated in pressure-demand or other positive-pressure mode
Small spills/leaks
Evacuate area and ventilate. Wear protective equipment. If required, use an inert absrobent. Sweep up and place in an appropriate container for disposal. Wash contaminated surfaces.
Stability
Trivalent chromium is the most stable oxidation state and hexavalent chromium is the second most stable state.
Incompatibilities
Avoid contact with oxidizing materials. In contact with substances which are readily oxidized these can react rapidly enough to cause ignition, and with finely divided oxidizable substances combustion can be violent. Dichromates hydrazine is decomposed explosively by chromates. Avoid contact with combustible organic, or other readily oxidizable materials.

Fire.
Fire fighting
Respiratory protection from chromic acid and chromates while fighting fires: Self-contained breathing apparatus with a full facepiece operated in pressure-demand or other positive pressure mode. Chromic acid and chromates extinguish fire using agent suitable for types of surrounding fire (material itself does not burn or burns with difficulty). 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.
Fire potential
It can react with combustible materials and the heat of this reaction may be sufficient to result in the ignition of the combustible material. In contact with substances which are readily oxidized these can react rapidly enough to cause ignition, and with finely divided oxidizable substances combustion can be violent. Decomp under heat to give off oxygen.

Health.
Exposure limit(s)
IDHL: NIOSH considers chromic acids and chromates to be potential occupational
Carcinogin
G-A1, I-1, N-1, CP65
Exposure effects
Hepatic encephalopathy, cerebral edema, and coma may occur. Both trivalent and hexavalent chromium have been found to cross the placental barrier in hamsters and mice. Both were shown to enter the fetus during mid to late gestation. Developmental effects caused by both differed between hamster and mice. Fetal uptake of hexavalent chromium was much greater than that of the trivalent form. Effects on placental tissue could have also affected the fetus.
   Ingestion
Gastroenteritis and hemorrhage frequently occur immediately following oral ingestion.
   Inhalation
Pulmonary edema, pneumoconiosis, metal fume fever, and bronchial asthma may occur.
   Skin
Deep perforating ulcers and hypersensitivity dermatitis may be noted. Systemic toxicity has resulted from minimal dermal exposure.

First aid
 
   Ingestion
Dilution: 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.
   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
Wash the exposed area with water or 10 to 20 percent ascorbic acid solution for 15 minutes. Consult a physician if irritation or pain persists.
   Eyes
Irrigate exposed eyes with copious amounts of tepid water for at least 15 minutes. If irritation, pain, swelling, lacrimation, or photophobia persist, the patient should be seen in a health care facility.

Transport.
USCG CHRIS Code
CCD