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Potassium dichromate

General description Solubility in water (g / 100ml) Non-coagulation type fixative Toxicity Chemical properties Uses Production method Category Toxicity classification Acute Toxicity Explosive hazardous properties Flammability and Hazardous characteristics Storage and transportation characteristics Fire extinguishing agent Professional Standard
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
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(25)

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 13450 Potassium dichromate, ACS, 99.0% min 7778-50-9 2.5kg $291 2017-11-08 Buy
Alfa Aesar 13450 Potassium dichromate, ACS, 99.0% min 7778-50-9 100g $42.9 2017-11-08 Buy
Strem Chemicals 93-1918 Potassium dichromate, 99+% (ACS) 7778-50-9 100g $40 2017-11-27 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

Solubility in water (g / 100ml)

Dissolved grams per 100 ml of water at different temperatures (° C):
7 g/10 ° C; 12.3 g/20 ° C; 18.1 g/30 ° C; 26.3 g/40 ° C
45.6 g/60 ° C; 73 g/80 ° C

Non-coagulation type fixative

The concentration of potassium dichromate used as fixed agent is commonly 1~3%. The water solution is slightly acidic. It is also a kind of strong oxidizer and therefore, should not be stored in advance with alcohol, formaldehyde, etc. Meanwhile, it is also as a strong sclerosis with weak penetration capability, thus rarely being used alone. Features: strong oxidants, hardening agent; weak penetration properties. It is often used in conjunction with other fixatives.


See sodium dichromate.

Chemical properties

It appears as orange-red monoclinic or triclinic crystal. It is slightly soluble in cold water, easily soluble in hot water with its solution being acidic. It is not soluble in alcohol.


It can be used for the production of chrome alum, chromium oxide green, chrome yellow pigments, welding electrodes, printing inks as well as used for tanning agents, enamel coloring agents and dyeing mordant
Enamel industry applies it for mixing with feldspar powder and quartz sand to calcine into enamel powder as green coloring agent. It can be used for modulation of the match head, playing the role of oxidation and moisture effect. It can be used as a tanning agent of light leather. It can be used as mordants for the medium dye dyeing and printing. It can be used as oxidizing agent for the synthetic perfume. It can be used for welding electrodes, printing inks and metal passivation. It can be used as the raw materials of the oxidants for organic synthesis and catalysts as well as pharmaceutical products.
It can be used for the manufacturing of chromium chemicals, mordant, ink, glass, spices, pigments, ceramics, varnish, explosives and pharmaceuticals, etc.
It can be used as an oxidant, for making chromium kalium and for the manufacture of chemical reagents
It can be used as reference reagent, redox titrant, chromatographic analysis reagent and oxidant as well as being used in organic synthesis

Production method

Double decomposition method: dilute and heat the sodium dichromate (or the mother liquor after the manufacturing of sodium dichromate); add the theoretical amount of potassium chloride (containing KCl> 90%) for metathesis with the reaction temperature is 105~110 ℃.
The concentration of the reaction solution is controlled at 37~38 °Bé under which to generate the sodium dichromate. Add a small amount of sodium chlorate, adjusting the pH value of the solution with sodium hydroxide to be 5-6; further add a small amount of aluminum sulfate to flocculate the impurity; remove the impurity after clarification; cool and crystallize the solution; further have centrifuge, washing and drying to obtain the finished product of potassium chromate. Its reaction equation is:
Na2Cr2O7 + 2KCl→ K2Cr2O7 + 2NaC1
The separated mother liquor, after subjecting to concentration, can have sodium chloride crystal precipitated out while the potassium dichromate is still dissolved in liquid phase. Separate the sodium chloride and wash with hot washing reagent and hot water with the washing agent being able to be combined with mother liquor of potassium dichromate for evaporation.
The mother liquor with sodium chloride separated, after the clarification, can have the insoluble removed out. The cooling of solution can again generate sodium dichromate crystals with secondary mother liquor being able to return to the reactor.



Toxicity classification

highly toxic

Acute Toxicity

Oral administration-mouse LD50: 190 mg/kg

Explosive hazardous properties

being explosive when being mixed with reducing agent, sulfur and phosphorus for heating, collision and friction.

Flammability and Hazardous characteristics

its combustion produces toxic chromium compounds and potassium oxide fumes

Storage and transportation characteristics

Treasury: ventilation, low temperature and drying; light loading and unloading; store it separately from organic matter, reducing agent, sulfur, phosphorus combustibles and food raw materials.

Fire extinguishing agent

mist water, sand

Professional Standard

TWA 0.05 mg (Cr)/m3

Chemical Properties

Orange solid


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.

Potassium dichromate Preparation Products And Raw materials

Raw materials

Preparation Products

Potassium dichromate Suppliers

Global( 214)Suppliers
Supplier Tel Fax Email Country ProdList Advantage
Hubei xin embellish DE chemical co., LTD 15871472056
027-51837617 China 322 58
J & K SCIENTIFIC LTD. 400-666-7788 +86-10-82848833
+86-10-82849933; China 96817 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 40398 62
Alfa Aesar 400-610-6006; 021-67582000
021-67582001/03/05 China 30309 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 12615 60
JinYan Chemicals(ShangHai) Co.,Ltd. 13817811078,021-50426030
86-021-50426522,50426273 China 10089 60
Adamas Reagent, Ltd. 400-600-9262 China 14018 59
Shanghai Hanhong Scientific Co.,Ltd. 021-54306202,021-54302127,021-54308259,13764082696
+86-21-54291107 China 31120 64

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