Substance profile
Potassium dichromate
Potassium dichromate is orange-red triclinic crystals and is odorless.
01 · Identification
What Potassium dichromate is
Potassium dichromate is orange-red triclinic crystals and is odorless. Its molecular formula is Cr2K2O7 and its molecular weight is 294.18 g/mol. It boils at 500 °C, melts at 398 °C.
Under the GHS it carries the signal word Danger. It is classed as carcinogens.
02 · Identifiers
Potassium dichromate identifiers and molecular data
Potassium dichromate CAS number and EC number
Potassium dichromate molecular formula and molecular weight
Other names for Potassium dichromate
- K2Cr2O7
- Bichromate Of Potash
- Bichrome
- Chromic Acid, Dipotassium Salt
- Chromium Potassium Oxide (K2Cr2O7)
- Dichromic Acid (H2Cr2O7), Dipotassium Salt
- Dichromic Acid Dipotassium Salt
- Dichromic Acid, Dipotassium Salt
- Dipotassium Bichromate
- Dipotassium Bichromate (K2Cr2O7)
- Dipotassium Dichromate
- Dipotassium Dichromate (K2Cr2O7)
- Dipotassium Dichromium Heptaoxide
03 · GHS classification
Potassium dichromate hazard classification
Harmonised classification under CLP Annex VI. This is the legally binding classification in the EU; other jurisdictions may differ.
Potassium dichromate pictograms and signal word
Potassium dichromate hazard class and category
| Hazard class | Category | From code | Pictogram |
|---|---|---|---|
| Oxidising liquids or Oxidising solids | Category 2 or 3 | H272 | GHS03 |
| Acute toxicity - oral GHS chapter 3.1 | Category 3 | H301 | GHS06 |
| Acute toxicity - dermal GHS chapter 3.1 | Category 4 | H312 | GHS07 |
| Acute toxicity - inhalation GHS chapter 3.1 | Category 1 or 2 | H330 | GHS06 |
| Skin corrosion/irritation GHS chapter 3.2 | Category 1A or 1B or 1C | H314 | GHS05 |
| Respiratory sensitisation GHS chapter 3.4 | Category 1 or 1A or 1B | H334 | GHS08 |
| Skin sensitisation GHS chapter 3.4 | Category 1 or 1A or 1B | H317 | GHS07 |
| Germ cell mutagenicity GHS chapter 3.5 | Category 1A or 1B | H340 | GHS08 |
| Carcinogenicity GHS chapter 3.6 | Category 1A or 1B | H350 | GHS08 |
| Specific target organ toxicity - repeated exposure GHS chapter 3.9 | Category 1 | H372 | GHS08 |
| Hazardous to the aquatic environment - acute GHS chapter 4.1 | Category 1 | H400 | GHS09 |
| Hazardous to the aquatic environment - chronic GHS chapter 4.1 | Category 1 | H410 | GHS09 |
Where two values are shown with “or”, the hazard statement is shared by more than one category or by more than one class, and the code alone does not say which. H272, for example, belongs to oxidising liquids and to oxidising solids — the physical state decides. The binding answer for a specific entry is in the CLP Annex VI table itself.
Potassium dichromate hazard statements (H-codes)
| Code | Hazard statement |
|---|---|
| H272 | May intensify fire; oxidiser. |
| H350 | May cause cancer <state route of exposure if it is conclusively proven that no other routes of exposure cause the hazard>. |
| H340 | May cause genetic defects <state route of exposure if it is conclusively proven that no other routes of exposure cause the hazard>. |
| H360FD | May damage fertility. May damage the unborn child. |
| H330 | Fatal if inhaled. |
| H301 | Toxic if swallowed. |
| H312 | Harmful in contact with skin. |
| H372 | Causes damage to organs <or state all organs affected, if known> through prolonged or repeated exposure <state route of exposure if it is conclusively proven that no other routes of exposure cause the hazard>. |
| H314 | Causes severe skin burns and eye damage. |
| H334 | May cause allergy or asthma symptoms or breathing difficulties if inhaled. |
| H317 | May cause an allergic skin reaction. |
| H400 | Very toxic to aquatic life. |
| H410 | Very toxic to aquatic life with long lasting effects. |
This page lists only the codes assigned to Potassium dichromate. The full reference lives on the hazard statements hub, the precautionary statements hub and the GHS pictograms hub.
Safety Data Sheet
Getting an SDS for Potassium dichromate
Our own Potassium dichromate safety data sheet walks through all sixteen sections of the published data. What it is not is the document an inspector asks for: an SDS is issued for a product by its supplier, so the sheet covering the grade actually standing in your store exists only in that supplier’s version. Collecting those and keeping them current as suppliers revise them is a separate job.
04 · Precautionary statements
Potassium dichromate precautionary statements
CLP Annex VI assigns 22 precautionary statements to Potassium dichromate. They are grouped the way a label groups them: what to do before handling, what to do when something has already happened, how to store it and how to dispose of it.
Prevention
What to do before and during handling so the hazard never happens.
Response
What to do once exposure, spillage or fire has already happened.
Disposal
What has to happen to the contents and the empty container.
Reading the notation. … is a blank the supplier fills in — not a truncated sentence.· [square brackets] mark a part printed only when it applies.
05 · Names in the regulation
Potassium dichromate name in 23 EU languages
CLP Annex VI Part 3 is published in every language edition of the regulation, and the identification column is written out in each of them. Nothing below is translated by us: each line is the name as that edition prints it. Under Art. 18(2) the substance name from Annex VI is a lawful product identifier, so this is the wording to put on a label going to that market — and where the cell lists several designations, any one of them qualifies.
| Language | Name in CLP Annex VI Part 3 |
|---|---|
| Bulgarian български | калиев дихромат |
| Spanish español | Dicromato de potasio |
| Czech čeština | dichroman draselný |
| Danish dansk | kaliumdichromat |
| German Deutsch | Kaliumdichromat |
| Estonian eesti | kaaliumdikromaat |
| Greek ελληνικά | διχρωμικό κάλιο |
| English English | potassium dichromate |
| French français | dichromate de potassium |
| Croatian hrvatski | kalijev dikromat |
| Italian italiano | dicromato di potassio |
| Latvian latviešu | kālija dihromāts |
| Lithuanian lietuvių | kalio dichromatas |
| Hungarian magyar | kálium-dikromát |
| Maltese Malti | dikromat tal-putassa |
| Dutch Nederlands | kaliumdichromaat |
| Polish polski | dichromian(VI) potasu |
| Portuguese português | dicromato de potássio |
| Romanian română | dicromat de potasiu |
| Slovak slovenčina | dichróman draselný |
| Slovenian slovenščina | kalijev dikromat |
| Finnish suomi | kaliumdikromaatti |
| Swedish svenska | kaliumdikromat |
All 23 language editions of Annex VI carry this entry. Irish is the twenty-fourth official EU language and has no line here for a different reason: no consolidated CLP text has ever been published in Irish, so there is no Irish edition of Annex VI to quote a name from. Source: consolidated CLP, CELEX 02008R1272, language editions. © European Union, https://eur-lex.europa.eu — only the electronic Official Journal of the European Union is authentic.
06 · Label elements
Potassium dichromate GHS label elements
Everything CLP Annex VI fixes for Potassium dichromate, laid out the way it appears on a label. The greyed lines are the parts only the supplier can fill in.
Danger
Potassium dichromate
- May intensify fire; oxidiser.
- May cause cancer <state route of exposure if it is conclusively proven that no other routes of exposure cause the hazard>.
- May cause genetic defects <state route of exposure if it is conclusively proven that no other routes of exposure cause the hazard>.
- May damage fertility. May damage the unborn child.
- Fatal if inhaled.
- Toxic if swallowed.
- Harmful in contact with skin.
- Causes damage to organs <or state all organs affected, if known> through prolonged or repeated exposure <state route of exposure if it is conclusively proven that no other routes of exposure cause the hazard>.
- Causes severe skin burns and eye damage.
- May cause allergy or asthma symptoms or breathing difficulties if inhaled.
- May cause an allergic skin reaction.
- Very toxic to aquatic life.
- Very toxic to aquatic life with long lasting effects.
- Obtain special instructions before use.
- Do not breathe dust/fume/gas/mist/vapours/spray.
- Avoid breathing dust/fume/gas/mist/vapours/spray.
- Do not eat, drink or smoke when using this product.
- Use only outdoors or in a well-ventilated area.
- Contaminated work clothing should not be allowed out of the workplace.
- Avoid release to the environment.
- Wear protective gloves/protective clothing/eye protection/face protection/hearing protection/…
- IF SWALLOWED:
- IF ON SKIN:
- IF INHALED:
- IF exposed or concerned:
- Immediately call a POISON CENTER/doctor/…
- Call a POISON CENTER/doctor/… if you feel unwell.
- Get medical advice/attention.
- Get medical advice/attention if you feel unwell.
- Rinse mouth.
- Do NOT induce vomiting.
- If skin irritation or rash occurs:
- Wash with plenty of water/…
- Collect spillage.
- Dispose of contents/container to …
Supplier name, address and telephone number· Product identifier·Nominal quantity
Need this as an actual label? Open Potassium dichromate in the GHS label constructor →
07 · Health hazards
Potassium dichromate health hazards and exposure limits
Potassium dichromate hazard 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.
Source: Haz-Map, Information on Hazardous Chemicals and Occupational Diseases
Potassium dichromate carcinogenicity classification
Cancer Classification: Not Likely to be Carcinogenic to Humans
Source: Hazardous Substances Data Bank (HSDB)
Evaluation: There is sufficient evidence in humans for the carcinogenicity of chromium(VI) compounds. Chromium(VI) compounds cause cancer of the lung. Also positive associations have been observed between exposure to Chromium(IV) compounds and cancer of the nose and nasal sinuses. There is sufficient evidence in experimental animals for the carcinogenicity of chromium(VI) compounds. Chromium(VI) compounds are carcinogenic to humans (Group 1). /Chromium(VI) compounds/
Source: Hazardous Substances Data Bank (HSDB)
An IARC group and a CLP classification answer different questions. IARC judges whether the evidence for cancer in humans is strong enough; CLP Annex VI is the legally binding EU classification. A substance can carry one and not the other.
Potassium dichromate occupational exposure limits
| Limit | Value | Source |
|---|---|---|
| PEL | 0.005 [mg/m3], as Cr(VI) | Haz-Map, Information on Hazardous Chemicals and Occupational Diseases |
| IDLH | 250 mg/cu m (as Cr(II)). /Chromium(II) compounds (as Cr)/ | Hazardous Substances Data Bank (HSDB) |
| IDLH | 25 mg/cu m (as Cr(III)). /Chromium(III) compounds (as Cr)/ | Hazardous Substances Data Bank (HSDB) |
| IDLH | 15 mg/cu m (as Cr(VI)). /Chromic acid and chromates/ | Hazardous Substances Data Bank (HSDB) |
These are United States values. The European Union sets its own indicative and binding limits, and the figure that applies at a given workplace is the one in the local regulation — not the one shown here.
08 · Physical and chemical properties
Potassium dichromate properties
Every value is shown with the conditions it was measured under and the source it came from. Where sources disagree, all values are listed rather than one being picked — the difference is usually a different form of the substance, not an error.
Potassium dichromate boiling point
| Property | Value | Conditions | Source |
|---|---|---|---|
| Boiling point | 500 °C (932 °F) | approximate | HSDB |
| 500 °C (932 °F) | decomposes | CAMEO |
Potassium dichromate melting point
| Property | Value | Conditions | Source |
|---|---|---|---|
| Melting point | 398 °C (748.4 °F) | HSDB | |
| 397.78 °C (748 °F) | CAMEO |
Potassium dichromate density
| Property | Value | Conditions | Source |
|---|---|---|---|
| Density | 2.7 g/cm³ | ICSC | |
| 2.676 g/cm³ | at 25 °C | HSDB |
Potassium dichromate solubility
| Property | Value | Conditions | Source |
|---|---|---|---|
| Solubility | 10 to 50 mg/mL at 68 °F (NTP, 1992) | at 20 °C | CAMEO |
| Solubility in water, g/100ml at 20 °C: 12 (moderate) | at 20 °C | ICSC | |
| In water, 45,000 mg/L at 25 °C | at 25 °C | HSDB |
Potassium dichromate autoignition temperature
| Property | Value | Conditions | Source |
|---|---|---|---|
| Autoignition temperature | Not flammable (USCG, 1999) | CAMEO |
Values compiled from PubChem Laboratory Chemical Safety Summary. Temperatures converted to Fahrenheit for reference.
09 · Fire and explosion
Potassium dichromate fire and explosion behaviour
These are descriptions rather than measured values, so they are kept out of the table above and quoted here with the source that reported them.
Potassium dichromate fire potential
Dangerous fire risk in contact with organic materials.
Source: Hazardous Substances Data Bank (HSDB)
10 · Handling and storage
Potassium dichromate storage and handling
Potassium dichromate reactive group
CAMEO Chemicals places Potassium dichromate in the reactive groups Oxidizing Agents, Strong, Salts, Basic. Compatibility with other chemicals is worked out from the group, not from the individual substance — which is why two substances you have never seen react can still be flagged as a pair that must be separated.
A reactive group is a CAMEO Chemicals (US NOAA) grouping, not a GHS hazard class: it has no code, no category and no legal force. It is what the storage compatibility matrix on this site computes from.
Potassium dichromate safe 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.
Source: ILO-WHO International Chemical Safety Cards (ICSCs)
Potassium dichromate storage conditions
Keep container tightly closed in a dry and well-ventilated place. Storage class (TRGS 510): Oxidizing hazardous materials
Source: Hazardous Substances Data Bank (HSDB)
Potassium dichromate incompatible materials
Incompatible materials: Organic materials. Do not store near acids. Powdered metals, hydrazine.
Source: Hazardous Substances Data Bank (HSDB)
Potassium dichromate 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].
Source: CAMEO Chemicals
Planning storage for a mix of chemicals? Check Potassium dichromate in the storage compatibility matrix →
11 · Questions
Potassium dichromate — frequently asked questions
What is the CAS number of Potassium dichromate?
The CAS number of Potassium dichromate is 7778-50-9. Its EC number is 231-906-6.
What is the chemical formula of Potassium dichromate?
The molecular formula of Potassium dichromate is Cr2K2O7 and its molecular weight is 294.18 g/mol.
What does a Potassium dichromate label have to show?
Under CLP Annex VI the label for Potassium dichromate carries the pictograms Flame over circle, Skull and crossbones, Health hazard, Corrosion and Environment and the signal word is Danger.
Is Potassium dichromate flammable?
CLP Annex VI assigns Potassium dichromate no flammability hazard class. That is not a statement that it cannot burn: the harmonised list only records the hazards that were assessed for it.
Is Potassium dichromate a carcinogen?
Yes. CLP Annex VI classifies Potassium dichromate as a category 1A or 1B carcinogen and assigns it H350: may cause cancer.
What is the exposure limit for Potassium dichromate?
The US occupational exposure limit reported for Potassium dichromate is 0.005 [mg/m3], as Cr(VI) (Haz-Map, Information on Hazardous Chemicals and Occupational Diseases). Limits differ by country: the EU sets its own indicative and binding values, and the figure that applies at a given workplace is the one in the local regulation.
What is the boiling point of Potassium dichromate?
The boiling point reported for Potassium dichromate is 500 °C (932 °F), approximate (HSDB).
What is the melting point of Potassium dichromate?
The melting point reported for Potassium dichromate is 398 °C (748.4 °F) (HSDB).
How should Potassium dichromate be stored?
Keep container tightly closed in a dry and well-ventilated place. Storage class (TRGS 510): Oxidizing hazardous materials (Hazardous Substances Data Bank (HSDB))
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