Potassium Dichromate

1Identification

Name

Potassium Dichromate

IUPAC name

dipotassium;oxido-(oxido(dioxo)chromio)oxy-dioxochromium

CAS number

7778-50-9

EC number

231-906-6

Molecular formula

Cr2K2O7

Molecular weight

294.18 g/mol

InChIKey

KMUONIBRACKNSN-UHFFFAOYSA-N

SMILES

[O-][Cr](=O)(=O)O[Cr](=O)(=O)[O-].[K+].[K+]

PubChem CID

24502

Synonyms

POTASSIUM DICHROMATE, Potassium bichromate, Iopezite, Kaliumdichromat, Bichromate of potash, Potassium dichromate(VI), Dipotassium bichromate, Dipotassium dichromate, Dichromic acid dipotassium salt, Dipotassium dichromium heptaoxide, SRM 935a, Potassium chromate (K2Cr2O7), Kali bichromicum, Potassium dichromate (K2Cr2O7)

Recommended uses

• Used as a dry cell depolarizer and in dyeing, staining, leather tanning, bleaching, and oxidizing; Also used in medical practice as an external astringent, antiseptic, and caustic; [ChemIDplus] Used with tungsten and iron in pyrotechnic displays; [CAMEO] Used in painting, printing, wood staining, fabric waterproofing, and corrosion inhibiting; also used to make safety matches and to bleach palm oil, wax, and sponges; [Merck Index] Used as an intensifier in photographic development; Also used as a mordant in textile dyeing; [www.ci.tucson.az.us/arthazards/medium.html]
  Haz-Map, Information on Hazardous Chemicals and Occupational Diseases
• Battery Manufacturing [Category: Industry] Painting (Pigments, Binders, and Biocides) [Category: Paint] Using Disinfectants or Biocides [Category: Clean] Leather Tanning and Processing [Category: Industry] Photographic Processing [Category: Other] Textiles (Printing, Dyeing, or Finishing) [Category: Industry] Silk-Screen Printing [Category: Other]
  Haz-Map, Information on Hazardous Chemicals and Occupational Diseases
• Textile arts [Category: Hobbies] Applying metallic patinas [Category: Hobbies]
  Haz-Map, Information on Hazardous Chemicals and Occupational Diseases

Description

• Potassium bichromate appears as orange red crystals. Denser than water and soluble in water. No distinctive odor. May severely irritate the eyes and respiratory tract. Avoid contact with organic materials. Noncombustible. Used in pyrotehnic displays with tungsten and iron.
  CAMEO Chemicals
• Potassium dichromate is a potassium salt that is the dipotassium salt of dichromic acid. It has a role as a sensitiser, an allergen and an oxidising agent. It contains a dichromate(2-).
  ChEBI
• Potassium Dichromate is an orange to red colored, crystalline, inorganic compound that emits toxic chromium fumes upon heating. Potassium dichromate is highly corrosive and is a strong oxidizing agent. This substance is used in wood preservatives, in the manufacture of pigments and in photomechanical processes, but is mainly replaced by sodium dichromate. Potassium dichromate primarily affects the respiratory tract causing ulcerations, shortness of breath, bronchitis, pneumonia and asthma but can also affect the gastrointestinal tract, liver, kidneys and immune system.
  NCI Thesaurus (NCIt)

2Hazard identification

Signal word

Danger

Pictograms

GHS03, GHS05, GHS06, GHS08, GHS09

Classification source

Regulation (EC) No 1272/2008 of the European Parliament and of the Council

Precautionary statements

Other reported classifications

6 classification records exist across sources. Differences usually reflect purity, physical form or impurities.

Health hazards

• Highly corrosive to skin and mucous membranes. If ingested, causes violent gastroenteritis, peripheral vascular collapse, vertigo, muscle cramps, coma, and (later) toxic nephritis with glycosuria. Allergic reactions may also occur. (USCG, 1999)
  CAMEO Chemicals

Fire hazards

• Behavior in Fire: May decompose, generating oxygen. Supports the combustion of other materials. (USCG, 1999)
  CAMEO Chemicals
• Not combustible but enhances combustion of other substances. Risk of fire and explosion on contact with combustible substances.
  ILO-WHO International Chemical Safety Cards (ICSCs)

Hazards summary

• CrVI compounds are irritants, sensitizers, and may be corrosive to the skin. CrVI compounds are respiratory tract irritants and may cause pulmonary sensitization. CrVI may cause acute tubular necrosis and liver injury. [ATSDR Case Studies] Corrosive to skin; [CAMEO] A hexavalent chromium compound; [CHEMINFO] See Chromium and linked occupational diseases.
  Haz-Map, Information on Hazardous Chemicals and Occupational Diseases

3Composition / information on ingredients

This page describes the pure substance. Commercial products may be solutions or mixtures. Check Section 3 of your supplier's SDS for concentrations and other ingredients.

4First-aid measures

• EYES: First check the victim for contact lenses and remove if present. Flush victim's eyes with water or normal saline solution for 20 to 30 minutes while simultaneously calling a hospital or poison control center. Do not put any ointments, oils, or medication in the victim's eyes without specific instructions from a physician. IMMEDIATELY transport the victim after flushing eyes to a hospital even if no symptoms (such as redness or irritation) develop. SKIN: IMMEDIATELY flood affected skin with water while removing and isolating all contaminated clothing. Gently wash all affected skin areas thoroughly with soap and water.
  CAMEO Chemicals

Symptoms of exposure

• Burning sensation. Sore throat. Cough. Wheezing. Laboured breathing.
  ILO-WHO International Chemical Safety Cards (ICSCs)
• Redness. Pain. Skin burns.
  ILO-WHO International Chemical Safety Cards (ICSCs)
• Redness. Pain. Blurred vision. Severe deep burns.
  ILO-WHO International Chemical Safety Cards (ICSCs)

5Fire-fighting measures

• Suitable extinguishing media: Use water spray, alcohol-resistant foam, dry chemical or carbon dioxide.
  Hazardous Substances Data Bank (HSDB)
• Advice for firefighters: Wear self-contained breathing apparatus for firefighting if necessary.
  Hazardous Substances Data Bank (HSDB)
• Use water spray to cool unopened containers.
  Hazardous Substances Data Bank (HSDB)

Hazardous combustion products

• Special hazards arising from the substance or mixture: Potassium oxides, Chromium oxides
  Hazardous Substances Data Bank (HSDB)

6Accidental release measures

Isolation and evacuation

• Excerpt from ERG Guide 141 [Oxidizers - Toxic]: IMMEDIATE PRECAUTIONARY MEASURE: Isolate spill or leak area in all directions for at least 50 meters (150 feet) for liquids and at least 25 meters (75 feet) for solids. LARGE SPILL: Consider initial downwind evacuation for at least 100 meters (330 feet). FIRE: If tank, rail tank car or highway tank is involved in a fire, ISOLATE for 800 meters (1/2 mile) in all directions; also, consider initial evacuation for 800 meters (1/2 mile) in all directions. (ERG, 2024)
  CAMEO Chemicals

Spill cleanup

• Personal protection: complete protective clothing including self-contained breathing apparatus. Sweep spilled substance into covered non-combustible containers. If appropriate, moisten first to prevent dusting. Carefully collect remainder. Then store and dispose of according to local regulations. Do NOT absorb in saw-dust or other combustible absorbents. Do NOT let this chemical enter the environment.
  ILO-WHO International Chemical Safety Cards (ICSCs)
• ACCIDENTAL RELEASE MEASURES: Personal precautions, protective equipment and emergency procedures: Wear respiratory protection. Avoid dust formation. Avoid breathing vapors, mist or gas. Ensure adequate ventilation. Evacuate personnel to safe areas. Avoid breathing dust; Environmental precautions: Prevent further leakage or spillage if safe to do so. Do not let product enter drains. Discharge into the environment must be avoided; Methods and materials for containment and cleaning up: Sweep up and shovel. Contain spillage, and then collect with an electrically protected vacuum cleaner or by wetbrushing and place in container for disposal according to local regulations.
  Hazardous Substances Data Bank (HSDB)
• 1) Ventilate the area of spill. 2. Collect spilled material in the most convenient and safe manner and deposit in sealed containers for reclamation or for disposal in a secured sanitary landspill. Liquid containing chromic acid or chromates should be absorbed in vermiculite, dry sand, earth, or a similar material.
  Hazardous Substances Data Bank (HSDB)
• Environmental considerations: Land Spill: Dig a pit, pond, lagoon, holding area to contain liquid or solid material. /SRP: If time permits, pits, ponds, lagoons, soak holes, or holding areas should be sealed with an impermeable flexible membrane liner./ Cover solids with a plastic sheet to prevent dissolving in rain or fire fighting water. Dike surface flow using soil, sand bags, foamed polyurethane, or foamed concrete.
  Hazardous Substances Data Bank (HSDB)

7Handling and storage

• Provision to contain effluent from fire extinguishing. Separated from combustible substances, reducing agents and food and feedstuffs. Well closed. Store in an area without drain or sewer access.
  ILO-WHO International Chemical Safety Cards (ICSCs)
• Keep container tightly closed in a dry and well-ventilated place. Storage class (TRGS 510): Oxidizing hazardous materials
  Hazardous Substances Data Bank (HSDB)
• ... Store in a location separate from other materials, especially flammables and combustibles. ... Store in a secure poison location. ... Potassium chromates must be stored to avoid contact with combustible, organic, or other easily oxidized materials (such as paper, wood, sulfur, aluminum, hydrazine, and plastics) since violent reactions occur. A regulated, marked area should be established where potassium chromate is handled, used, or stored. Where possible, automatically transfer material from drums or other storage containers to process containers. Sources of ignition, such as smoking and open flames, are prohibited where this chemical is handled, used, or stored.
  Hazardous Substances Data Bank (HSDB)

8Exposure controls / personal protection

Personal protective equipment

• Approved dust mask; protective gloves; goggles or face shield. (USCG, 1999)
  CAMEO Chemicals
• Eye/face protection: Face shield and safety glasses. Use equipment for eye protection tested and approved under appropriate government standards such as NIOSH (US) or EN 166(EU).
  Hazardous Substances Data Bank (HSDB)
• Skin protection: Handle with gloves.
  Hazardous Substances Data Bank (HSDB)
• Body Protection: Complete suit protecting against chemicals. The type of protective equipment must be selected according to the concentration and amount of the dangerous substance at the specific workplace.
  Hazardous Substances Data Bank (HSDB)

9Physical and chemical properties

10Stability and reactivity

Reactivity

• Potassium or sodium dichromate reacts explosively with hydrazine [Mellor 11:234. 1946-47]. A drop of anhydrous hydroxylamine on powdered potassium dichromate produces a violent explosion [Mellor 8:293. 1946-47].
  CAMEO Chemicals
• Soluble in water.
  CAMEO Chemicals

Incompatible materials and hazardous reactions

• Incompatible materials: Organic materials. Do not store near acids. Powdered metals, hydrazine.
  Hazardous Substances Data Bank (HSDB)
• Potassium dichromate ... reacts explosively with hydrazine.
  Hazardous Substances Data Bank (HSDB)
• A drop of anhydrous hydroxylamine on powdered potassium dichromate produces a violent explosion.
  Hazardous Substances Data Bank (HSDB)

Chemical stability

• Stable under recommended storage conditions.
  Hazardous Substances Data Bank (HSDB)

11Toxicological information

Short-term exposure effects

• The substance is corrosive to the eyes, skin and respiratory tract. Corrosive on ingestion. The substance may cause effects on the kidneys and liver. This may result in tissue lesions.
  ILO-WHO International Chemical Safety Cards (ICSCs)

Long-term exposure effects

• Repeated or prolonged contact may cause skin sensitization. Repeated or prolonged inhalation may cause asthma. Repeated or prolonged inhalation may cause nasal ulceration. This may result in perforation of the nasal septum. The substance may have effects on the kidneys. This may result in kidney impairment. This substance is carcinogenic to humans. Animal tests show that this substance possibly causes toxicity to human reproduction or development.
  ILO-WHO International Chemical Safety Cards (ICSCs)

12Ecological information

Not available in the public sources we compile. Check Section 12 of the supplier's SDS.

13Disposal considerations

• Generators of waste (equal to or greater than 100 kg/mo) containing this contaminant, EPA hazardous waste number D007, must conform with USEPA regulations in storage, transportation, treatment and disposal of waste. /Chromium/
  Hazardous Substances Data Bank (HSDB)
• Product: Burn in a chemical incinerator equipped with an afterburner and scrubber but exert extra care in igniting as this material is highly flammable. Offer surplus and non-recyclable solutions to a licensed disposal company. Contact a licensed professional waste disposal service to dispose of this material. Dissolve or mix the material with a combustible solvent and burn in a chemical incinerator equipped with an afterburner and scrubber; Contaminated packaging: Dispose of as unused product.
  Hazardous Substances Data Bank (HSDB)
• SRP: Wastewater from contaminant suppression, cleaning of protective clothing/equipment, or contaminated sites should be contained and evaluated for subject chemical or decomposition product concentrations. Concentrations shall be lower than applicable environmental discharge or disposal criteria. Alternatively, pretreatment and/or discharge to a permitted wastewater treatment facility is acceptable only after review by the governing authority and assurance that "pass through" violations will not occur. Due consideration shall be given to remediation worker exposure (inhalation, dermal and ingestion) as well as fate during treatment, transfer and disposal.
  Hazardous Substances Data Bank (HSDB)

14Transport information

DOT label

• Oxidizer Poison
  CAMEO Chemicals

UN classification

• UN Hazard Class: 6.1; UN Pack Group: II
  ILO-WHO International Chemical Safety Cards (ICSCs)

Not available in the public sources we compile. Check Section 14 of the supplier's SDS.

How DOT hazard classes work →

15Regulatory information

• ... Substances for which a Federal Register notice has been published that included consideration of the serious health effects, including cancer, from ambient air exposure to the substance. Chromium is included on this list. /Chromium/
  Hazardous Substances Data Bank (HSDB)
• As the federal pesticide law FIFRA directs, EPA is conducting a comprehensive review of older pesticides to consider their health and environmental effects and make decisions about their future use. Under this pesticide reregistration program, EPA examines health and safety data for pesticide active ingredients initially registered before November 1, 1984, and determines whether they are eligible for reregistration. In addition, all pesticides must meet the new safety standard of the Food Quality Protection Act of 1996.
  Hazardous Substances Data Bank (HSDB)
• Potassium dichromate is designated as a hazardous substance under section 311(b)(2)(A) of the Federal Water Pollution Control Act and further regulated by the Clean Water Act Amendments of 1977 and 1978. These regulations apply to discharges of this substance. This designation includes any isomers and hydrates, as well as any solutions and mixtures containing this substance.
  Hazardous Substances Data Bank (HSDB)
• Toxic pollutant designated pursuant to section 307(a)(1) of the Federal Water Pollution Control Act and is subject to effluent limitations. /Chromium and compounds/
  Hazardous Substances Data Bank (HSDB)
• Persons in charge of vessels or facilities are required to notify the National Response Center (NRC) immediately, when there is a release of this designated hazardous substance, in an amount equal to or greater than its reportable quantity of 10 lb or 4.54 kg. The toll free number of the NRC is (800) 424-8802. The rule for determining when notification is required is stated in 40 CFR 302.4 (section IV.D.3.b).
  Hazardous Substances Data Bank (HSDB)
• D007; A solid waste containing chromium may or may not become characterized as a hazardous waste when subjected to the Toxicity Characteristic Leaching Procedure listed in 40 CFR 261.24, and if so characterized, must be managed as a hazardous waste. /Chromium/
  Hazardous Substances Data Bank (HSDB)

Overview of SDS regulations (OSHA HazCom, WHMIS, REACH/CLP) →

16Other information

Compiled from PubChem CID 24502 and the sources it aggregates (attributed inline). Data retrieved 2026-10-12. This summary describes the pure substance and is not a supplier SDS.