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Potassium dichromate

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Potassium dichromate
Potassium dichromate
Chemical Name:
Potassium dichromate
iopezite;CHROMIUM METAL;HTM BROTH 100ML;kaliumdichromat;CHROMIUM POWDER;CHROMIUM STANDARD;UV-VIS STANDARD 1;bichromateofpotash;potassiumdichromate6;Redpotassiumchromate
Molecular Formula:
Formula Weight:
MOL File:

Potassium dichromate Properties

Melting point:
4 °C
Boiling point:
82 °C
7.14 g/mL at 25 °C(lit.)
Flash point:
50 °F
storage temp. 
Store at RT.
H2O: 0.1 M at 20 °C, clear, orange
3.5-5.0 (25℃, 0.1M in H2O)
Water Solubility 
125 g/L (20 ºC)
CAS DataBase Reference
7778-50-9(CAS DataBase Reference)
EPA Substance Registry System
Chromic acid (H2Cr2O7), dipotassium salt(7778-50-9)
  • Risk and Safety Statements
  • Hazard and Precautionary Statements (GHS)
Hazard Codes  T,N,T+,O
Risk Statements  45-46-60-61-8-21-25-26-34-42/43-48/23-50/53-52/53-20-48/20-23-51/53-22-36/37/38-27-20/21-23/24
Safety Statements  53-45-60-61-36/37-23-26
RIDADR  UN 3086 6.1/PG 1
WGK Germany  3
RTECS  HX7680000
HazardClass  5.1
PackingGroup  III
HS Code  28415000
Hazardous Substances Data 7778-50-9(Hazardous Substances Data)
Signal word: Danger
Hazard statements:
Code Hazard statements Hazard class Category Signal word Pictogram P-Codes
H272 May intensify fire; oxidizer Oxidising liquids;Oxidising solids Category 2
Category 3
P210, P220, P221P280, P370+P378,P501
H301 Toxic if swalloed Acute toxicity,oral Category 3 Danger P264, P270, P301+P310, P321, P330,P405, P501
H303 May be harmfulif swallowed Acute toxicity,oral Category 5 P312
H312 Harmful in contact with skin Acute toxicity,dermal Category 4 Warning P280,P302+P352, P312, P322, P363,P501
H314 Causes severe skin burns and eye damage Skin corrosion/irritation Category 1A, B, C Danger P260,P264, P280, P301+P330+ P331,P303+P361+P353, P363, P304+P340,P310, P321, P305+ P351+P338, P405,P501
H315 Causes skin irritation Skin corrosion/irritation Category 2 Warning P264, P280, P302+P352, P321,P332+P313, P362
H317 May cause an allergic skin reaction Sensitisation, Skin Category 1 Warning P261, P272, P280, P302+P352,P333+P313, P321, P363, P501
H318 Causes serious eye damage Serious eye damage/eye irritation Category 1 Danger P280, P305+P351+P338, P310
H319 Causes serious eye irritation Serious eye damage/eye irritation Category 2A Warning P264, P280, P305+P351+P338,P337+P313P
H330 Fatal if inhaled Acute toxicity,inhalation Category 1, 2 Danger P260, P271, P284, P304+P340, P310,P320, P403+P233, P405, P501
H331 Toxic if inhaled Acute toxicity,inhalation Category 3 Danger P261, P271, P304+P340, P311, P321,P403+P233, P405, P501
H333 May be harmful if inhaled Acute toxicity,inhalation Category 5 P304+P312
H334 May cause allergy or asthma symptoms or breathing difficulties if inhaled Sensitisation, respiratory Category 1 Danger P261, P285, P304+P341, P342+P311,P501
H340 May cause genetic defects Germ cell mutagenicity Category 1A, 1B Danger
H350 May cause cancer Carcinogenicity Category 1A, 1B Danger
H360 May damage fertility or the unborn child Reproductive toxicity Category 1A, 1B Danger
H372 Causes damage to organs through prolonged or repeated exposure Specific target organ toxicity, repeated exposure Category 1 Danger P260, P264, P270, P314, P501
H373 May cause damage to organs through prolonged or repeated exposure Specific target organ toxicity, repeated exposure Category 2 Warning P260, P314, P501
H400 Very toxic to aquatic life Hazardous to the aquatic environment, acute hazard Category 1 Warning P273, P391, P501
H401 Toxic to aquatic life Hazardous to the aquatic environment, acute hazard Category 2 P273, P501
H402 Harmful to aquatic life Hazardous to the aquatic environment, acute hazard Category 3
H410 Very toxic to aquatic life with long lasting effects Hazardous to the aquatic environment, long-term hazard Category 1 Warning P273, P391, P501
H411 Toxic to aquatic life with long lasting effects Hazardous to the aquatic environment, long-term hazard Category 2
H412 Harmful to aquatic life with long lasting effects Hazardous to the aquatic environment, long-term hazard Category 3 P273, P501
Precautionary statements:
P201 Obtain special instructions before use.
P202 Do not handle until all safety precautions have been read and understood.
P221 Take any precaution to avoid mixing with combustibles/…
P260 Do not breathe dust/fume/gas/mist/vapours/spray.
P280 Wear protective gloves/protective clothing/eye protection/face protection.
P284 Wear respiratory protection.
P320 Specific treatment is urgent (see … on this label).
P303+P361+P353 IF ON SKIN (or hair): Remove/Take off Immediately all contaminated clothing. Rinse SKIN with water/shower.
P304+P340 IF INHALED: Remove victim to fresh air and Keep at rest in a position comfortable for breathing.
P305+P351+P338 IF IN EYES: Rinse cautiously with water for several minutes. Remove contact lenses, if present and easy to do. Continuerinsing.
P308+P313 IF exposed or concerned: Get medical advice/attention.
P405 Store locked up.

Potassium dichromate price More Price(33)

Manufacturer Product number Product description CAS number Packaging Price Updated Buy
Sigma-Aldrich 1.02403 Potassium dichromate 7778-50-9 1EA $83 2017-11-08 Buy
Sigma-Aldrich 1.04864 Potassium dichromate 7778-50-9 1EA $180 2017-11-08 Buy
Alfa Aesar 013450 Potassium dichromate, ACS, 99.0% min 7778-50-9 2.5kg $272 2018-11-16 Buy
Alfa Aesar 013450 Potassium dichromate, ACS, 99.0% min 7778-50-9 100g $38.3 2018-11-16 Buy
Strem Chemicals 93-1918 Potassium dichromate, 99+% (ACS) 7778-50-9 100g $40 2018-11-13 Buy

Potassium dichromate Chemical Properties,Uses,Production

General description

Potassium dichromate (Formula K2Cr2O7) will be decomposed and releases oxygen under the white heat temperature. It has strong oxidizing property, being a strongly toxic and carcinogenic oxidant. It appears as orange-red solid at room temperature and plate crystal. It has been classified as a Category I carcinogen by the International Agency for Research on Cancer (IARC), and may be combustible when come into contact with combustibles. At temperature above 500 ° C, it can lead to oxidation to generate chromic acid and chromium oxide. Potassium dichromate has very small solubility at low temperature and does not contain crystal water. It is easily purified through recrystallization; also not easy to have deliquescence and thus often being used as the reference standard in the analysis.
Owing to the strong oxidizing properties of potassium dichromate under acidic conditions, it is commonly used in the laboratory to formulate a chromic acid washing agent (a mixture of saturated potassium dichromate solution and concentrated sulfuric acid) for washing the chemical glassware in order to remove the reductive dirt in the glass wall. After use, the washing agent changes from dark red to green color under which the washing agent becomes invalid. Potassium dichromate can also used be in analytical chemistry, commonly used to determine the reductive hydrogen sulfide, sulfurous acid, ferrous ions and so on. Upon the heating, potassium dichromate can also oxidize concentrated hydrochloric acid to release chlorine.
As the raw materials for the production of leather hydrolysates are mainly from the corner of the tannery factory waste, and these wastes often contain potassium dichromate and sodium dichromate, during the production of hydrolyzed protein, potassium dichromate, sodium dichromate will be naturally brought into the dairy products. Human drinking can lead to joint osteoporosis, swelling and other poisoning problems. Chroming workers subjecting to repeated or long-term exposure to low concentrations of chromium compounds can get chronic upper respiratory tract inflammation, chrome rhinopathy, contact dermatitis and rash which mainly occur in naked places such as the face, neck, hands and forearm. It can also cause kidney and liver damage as well as causing blood system changes. The occurrence of lung cancer has a incubation period of 10-20 years.
Figure 1 the molecular structure of the potassium dichromate
Figure 1 the molecular structure of the potassium dichromate


Potassium bichromate is an odorless substance that can be found naturally occurring in the environment, for instance, in ash, sand, loam, and clay. The chemical occurs in steel-made tools, and chrome-plated objects such as needles, silverware, handles, and bracelets. Furthermore, potassium dichromate is used as a component of fur-tanning agents, leather, dark textile dyes, epoxy hardeners, chromium pigments, and photographic color developer. The orange-red color powdered substance has a melting point of 398oC and a molecular weight of 294 gram (g)/mol. Notably, the chemical is soluble in water and ethyl alcohol.


The production of potassium bichromate begins with the reaction of chromium trioxide and potassium hydroxide in a reactor generating a mother liquor.
2 CrO3 + 2 KOH = K2Cr2O7 + H2O
The next step is filtration of the mother liquor and the ensuing filter solids are put aside for disposal. The remaining substance is then sent for precipitation of crystalline potassium bichromate through a centrifugation process. Finally, the mother liquor from the centrifuge is sent back to the reactor.


Potassium bichromate is an inorganic oxidizing agent that has multiple scientific and industrial uses.
Potassium bichromate has significant uses in photographic screen-printing and photography where together with strong mineral acid, they can be used as an oxidizing agent. In the 1850s, gum bichromate printing was largely used in the photographic printing processes. It is worth noting that when exposed to ultraviolet light, a solution of potassium bichromate and gum Arabic will be dried and hardened. Together with concentrated hydrochloric acid (HCL), photochromos and chromium uses potassium bichromate to treat thin and weak negatives of black and white photograph roll. The solution of HCL together with potassium bichromate reconverts the particles of silver in the film to silver chloride. The film is the exposed to actinic light and then redeveloped to its end product, giving out a more stronger negative and a acceptable print. In sulfuric acid, potassium bichromate solution can be used to manufacture a reversal negative.
Industrial Uses
Manufacturers in the textile industry use the chemical in dying clothe fabrics and tanning leather. In addition, potassium bichromate is normally used in decorative chromium plating as well as coating active metals such as steel and aluminum to prevent them from corrosion. In science, the substance is used as a solvent and in the identification of certain elements in solutions. In the furniture industry, the chemical is used in straining wood.

Health Effects

Acute Health Effects 
Potassium bichromate, similar to other chromate compounds can cause acute health effects if inhaled or ingested. The chemical can cause irritation in the lungs or throats of some individuals. Chrome fumes and dust are irritating to the lungs and respiratory tract. Toxic effects due to over exposure may lead to asthmatic conditions. Accidental ingestion of the chemical may lead to toxic effects. 
Potassium bichromate may result to chemical burns within the gastrointestinal tract and oral cavity if swallowed. It is noteworthy that acute poisoning from the substance is minimal since vomiting or renal excretion occurs immediately after swallowing. However, swallowing the chemical can lead to extreme thirst, loss of appetite, fever, augmented volumes of urine, gastric imbalances, and convulsions. Due to failure of breathing and inflammation of the bowel and the stomach, an individual can die following the swallowing of potassium bichromate. 
Following direct contact to the eye, the chemical can produce burns and cause severe damage. If in contact with the skin and absorbed, potassium bichromate may lead to chemical burns. In addition, chrome fumes such as chrome oxide may exacerbate current skin conditions, for instance, eczema or dermatitis, and can lead to severe damage to the skin. Also, absorption through the skin may lead to poisoning affecting the liver and kidneys. It is essential to note that the substance should not come to contact with open cuts, lesions, or abrasions as it may produce systemic injuries if it enters the blood stream. 
Chronic Health Effects
Potassium bichromate is a mutagen and a carcinogen, therefore can cause cancer in humans due to prolonged exposure. In addition, lengthy exposure inside the mouth can lead to ulcerative and inflammatory changes in the mouth and erosion of the teeth. Recurrent attach of bronchial pneumonia and the gastrointestinal disturbances may ensue. Inhalation and skin contact with potassium bichromate may result to sensitization reaction is particular individuals. Interestingly, the substance can lead to genetic defects as well as reduced fertility in humans. 

Waste Disposal

No waste solutions of potassium chromate should be drained, as they can cause detrimental effects to the environment. In addition, all powdered materials should be disposed as hazardous waste. Generally, all disposable materials as well as decontamination from non-disposable tools or equipment must be disposed ass hazardous waste.


  4. Jessica Jacobs. What Is Potassium Chromate Used For?

Chemical Properties

Also known as potassium bichromate and red potassium chromate, K2Cr2O7 is poisonous,yellowish-red crystals with a metallic taste that is soluble in water,insoluble in alcohol,that melt at 396℃;and decompose at 500℃. Used as an oxidizing agent and analytical reagent,and in explosives, matches, and electroplating.


ChEBI: A potassium salt that is the dipotassium salt of dichromic acid.


In tanning leather, dyeing, painting, decorating porcelain, printing, photolithography, pigment-prints, staining wood, pyrotechnics, safety matches; for bleaching palm oil, wax, and sponges; waterproofing fabrics; as oxidizer in the manufacture of organic chemicals; in electric batteries; as depolarizer for dry cells. As corrosion inhibitor in preference to sodium dichromate where lower soly is advantageous. Pharmaceutic aid (oxidizing agent).

General Description

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.

Air & Water Reactions

Soluble in water.

Reactivity Profile

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].

Health Hazard

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.

Fire Hazard

Behavior in Fire: May decompose, generating oxygen. Supports the combustion of other materials.

Purification Methods

Crystallise it from water (g/mL) between 100o and 0o and dry it under vacuum at 156o. (Possible CARCINOGEN.)

Potassium dichromate Preparation Products And Raw materials

Raw materials

Preparation Products

Potassium dichromate Suppliers

Global( 218)Suppliers
Supplier Tel Fax Email Country ProdList Advantage
Mainchem Co., Ltd.
+86-0592-6210733 CHINA 32764 55
City Chemical LLC
203.937.8400 United States 101 58
Hubei xin embellish DE chemical co., LTD 15871472056
027-51837617 China 388 58
J & K SCIENTIFIC LTD. 400-666-7788 +86-10-82848833
+86-10-82849933; China 96815 76
Meryer (Shanghai) Chemical Technology Co., Ltd. +86-(0)21-61259100(Shanghai) +86-(0)755-86170099(ShenZhen) +86-(0)10-62670440(Beijing)
+86-(0)21-61259102(Shanghai) +86-(0)755-86170066(ShenZhen) +86-(0)10-88580358(Beijing) China 40399 62
Alfa Aesar 400-610-6006; 021-67582000
021-67582001/03/05 China 30308 84
Beijing dtftchem Technology Co., Ltd. 13651141086; 86(10)60275028、60275820
86 (10) 60270825 China 1443 62
Energy Chemical 021-58432009 / 400-005-6266
021-58436166-800 China 44192 61
Beijing Ouhe Technology Co., Ltd +86-10-4006331231;+86-10-51280831;+86-10-82967028
+86-10-82967029 China 12613 60
JinYan Chemicals(ShangHai) Co.,Ltd. 13817811078,021-50426030
86-021-50426522,50426273 China 10088 60

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