Potassium Dichromate

HCID 24502CAS 7778-50-9

Basic information

Standard SMILES
[K+].[K+].[O]=[Cr](=[O])([O-])[O][Cr](=[O])(=[O])[O-]
InChIKey
KMUONIBRACKNSN-UHFFFAOYSA-N
Molecular formula
K2Cr2O7
Average molar mass
294.18 g/mol
Monoisotopic mass
293.7728307

Overview

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.

Names & identifiers

Preferred name
Potassium Dichromate
IUPAC
dipotassium;oxido-(oxido(dioxo)chromio)oxy-dioxochromium

Names & synonyms

POTASSIUM DICHROMATE7778-50-9Potassium bichromateIopeziteKaliumdichromatBichromate of potashPotassium dichromate(VI)Dipotassium bichromateDipotassium dichromateDichromic acid dipotassium saltDipotassium dichromium heptaoxideDTXSID5025948
Show more names
SRM 935aPotassium chromate (K2Cr2O7)Kali bichromicumPotassium dichromate (K2Cr2O7)Chromic acid (H2Cr2O7), dipotassium saltPotassium dichromate (K2(Cr2O7))Chromium potassium oxide (K2Cr2O7)Dichromic acid, dipotassium salt

Database identifiers

CAS
7778-50-9
PubChem CID
24502
DTXSID
DTXSID5025948
ChEMBL
CHEMBL1374101
ChEBI
CHEBI:53444
UNII
T4423S18FM
EC Number
231-906-6

Properties

Computed structural properties

Topological polar surface area
124 Ų
Hydrogen bond donors
0
Hydrogen bond acceptors
7
Rotatable bonds
0
Heavy atoms
11

Experimental & physicochemical properties

Chemical Classes · 2 items

Metals -> Chromium Compounds, Inorganic

Carcinogens

pHAcid reaction: a 1% aqueous solution has pH of 4.04 and a 10% solution has a pH of 3.57
OdorOdorless, no distinctive odor
TasteBitter, metallic taste
Density · 5 items

2.676 at 77 °F (USCG, 1999) - Denser than water; will sink

2.676 at 25 °C/4 °C

Crystal system: triclinic pinacoidal, transition to monoclinic at 241.6 °C; not hygroscopic or deliquescent; crystal habit: prismatic; bulk density: 100 lb/cu ft; heat of solution: -62.5 cal/g; specific heat: 0.186 at 16-98 °C; heat of fusion: 29.8 cal/g

2.7 g/cm³

2.68 @25 °C

Color/Form · 2 items

Orange-red triclinic crystals

Bright orange-red crystals

Safety & regulation

GHS classification

GHS Classification · 6 items

Danger

H272: May intensify fire; oxidizer [Danger Oxidizing liquids; Oxidizing solids]

P203, P210, P220, P233, P260, P261, P264, P270, P271, P272, P273, P280, P284, P301+P316, P301+P330+P331, P302+P352, P302+P361+P354, P304+P340, P305+P354+P338, P316, P317, P318, P319, P320, P321, P330, P333+P317, P342+P316, P362+P364, P363, P370+P378, P391, P403, P403+P233, P405, and P501 (click each P-code to see the statement)

This chemical does not meet GHS hazard criteria for 0.2% (1 of 491) of reports.

Danger

H272 (92.3%): May intensify fire; oxidizer [Danger Oxidizing liquids; Oxidizing solids]

Hazard information

Regulatory Information · 6 items

Chemical: Chromic acid (H2Cr2O7), dipotassium salt

Hazard Traits - Carcinogenicity; Genotoxicity; Reproductive Toxicity; Respiratory Toxicity

R - indicates a substance that is the subject of a TSCA section 6 risk management rule.

Status: Active Update: 15-12-2021 https://echa.europa.eu/registration-dossier/-/registered-dossier/15102

Substance: Potassium dichromate

Chromic acid, dipotassium salt: HSNO Approval: HSR001437 Approved with controls

Other Safety InformationIMAP assessments - Chromates and dichromates (soluble): Human health tier II assessment
DOT LabelOxidizer Poison
Fire Hazards · 2 items

Behavior in Fire: May decompose, generating oxygen. Supports the combustion of other materials. (USCG, 1999)

Not combustible but enhances combustion of other substances. Risk of fire and explosion on contact with combustible substances.

Fire Potential · 2 items

Dangerous fire risk in contact with organic materials.

Flammable by chemical reaction.

Health Hazards · 1 item

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)

Safety & protection

Fire Fighting · 2 items

Excerpt from ERG Guide 141 [Oxidizers - Toxic]:

In case of fire in the surroundings, use appropriate extinguishing media.

First Aid Measures · 4 items

Fresh air, rest. Half-upright position. Artificial respiration may be needed. Refer for medical attention.

First rinse with plenty of water for at least 15 minutes, then remove contaminated clothes and rinse again. Refer for medical attention .

First rinse with plenty of water for several minutes (remove contact lenses if easily possible), then refer for medical attention.

Rinse mouth. Do NOT induce vomiting. Give one or two glasses of water to drink. Refer for medical attention .

First Aid · 1 item

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.

Safe StorageProvision 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.
Exposure Control and Personal Protection · 1 item

TIH (Toxic Inhalation Hazard) - Term used to describe gases and volatile liquids that are toxic when inhaled. Some are TIH materials themselves, e.g., chlorine, and some release TIH gases when spilled in water, e.g., chlorosilanes. [ERG 2016].

Fire Fighting Procedures · 5 items

Suitable extinguishing media: Use water spray, alcohol-resistant foam, dry chemical or carbon dioxide.

Advice for firefighters: Wear self-contained breathing apparatus for firefighting if necessary.

Use water spray to cool unopened containers.

If material involved in fire: Extinguish fire using agent suitable for type of surrounding fire (Material itself does not burn or burns with difficulty.)

For more Fire Fighting Procedures (Complete) data for POTASSIUM DICHROMATE (6 total), please visit the HSDB record page.

Toxicology

TreatmentThere is no know antidote for chromium poisoning. Exposure is usually handled with symptomatic treatment. (L16)
Interactions · 5 items

Potassium dichromate enhanced the effects of mercuric chloride or citrinin on renal slice transport of the organic ions p-aminohippurate & tetraethylammonium under certain experimental conditions. At the doses employed & times studied no effects, or only minimal effects were observed on renal slice transport when the toxic compounds were tested individually. Potassium dichromate (10 mg/kg sc) in combination with mercuric chloride (4 mg/kg, sc) or citrinin (35 or 55 mg/kg, ip), resulted in marked depression of organic ion transport. Similarly, the addition of potassium dichromate to fresh renal cortex slices in combination with mercuric chloride, enhanced the mercuric chloride-induced reduction of transport. No other interactions were observed under in vitro conditions.

The interaction between nitrilotriacetic acid and soluble chromium(IV), ie, potassium dichromate (K2Cr2O7), was studied by the Ames test on Salmonella typhimurium strains TA100, TA92, TA104 and TA103, and the sex linked recessive lethal test on Drosophila melanogaster. For the Ames test, potassium dichromate (0, 10, 15, or 20 ug/plate) was dissolved in distilled water or in different concn of nitrilotriacetic acid in water (1%, 5%, or 10% wt/vol). For the Drosophila, adult feeding (for 24 hr) was the route of admin of potassium dichromate (50 mM) and nitrilotriacetic acid (50 mM) dissolved in a 5% sucrose solution. With all the Salmonella strains the dose response curves showed a synergistic effect of nitrilotriacetic acid on potassium dichromate mutagenicity. The effect depended both on the genetic characteristics of the bacterial strains and the relative concn of dichromate and nitrilotriacetic acid. In the strains TA92 and TA103, the decline of revertants due to toxicity took place at 25 to 30 ug dichromate/plate. In a series comprising a large number of replicates, a statistically significant incr of revertants was produced by dichromate (15 ug/plate) and nitrilotriacetic acid (10%) compared to dichromate alone in all Salmonella strains. In the D melanogaster test, a significant dose related incr of lethal mutations was induced by dichromate both in the absence and presence of nitrilotriacetic acid (the regression lines gave t= 7.699, p < 0.005 without nitrilotriacetic acid and t= 5.112, p < 0.01 with. An in vitro assay was set up to measure in the presence or absence of nitrilotriacetic acid the reduction of potassium dichromate by proteins extracted from Salmonella or Drosophila. More Cr(VI) was reduced to Cr(III) by protein extracts in the presence of nitrilotriacetic acid. A similar enhancement of soluble Cr(VI) mutagenicity in S typhimurium TA92 was produced by 0.005 to 0.0005% ethylenediamine tetraacetic acid (EDTA).

This study aimed to assess the effect of ultraviolet radiation (UVR) and chemical stress (triclosan-TCS; potassium dichromate-PD; prochloraz-PCZ) on bacterial communities of zebrafish (Danio rerio) embryos (ZEBC). Embryos were exposed to two UVR intensities and two chemical concentrations not causing mortality or any developmental effect (equivalent to the No-Observed-Effect Concentration-NOEC; NOEC diluted by 10-NOEC/10). Effects on ZEBC were evaluated using denaturing gradient gel electrophoresis (DGGE) and interpreted considering structure, richness and diversity. ZEBC were affected by both stressors even at concentrations/doses not affecting the host-organism (survival/development). Yet, some stress-tolerant bacterial groups were revealed. The structure of the ZEBC was always affected, mainly due to xenobiotic presence. Richness and diversity decreased after exposure to NOEC of PD. Interactive effects occurred for TCS and UVR. Aquatic microbiota imbalance might have repercussions for the host/aquatic system, particularly in a realistic scenario/climate change perspective therefore, future ecotoxicological models should consider xenobiotics interactions with UVR.

At ecosystems level, environmental parameters such as temperature, pH, dissolved oxygen concentration and intensity of UV radiation (UVR) have an important role on the efficiency of organisms' physiological and behavioral performances and consequently on the capacity of response to contaminants. Insignificant alterations of these parameters may compromise this response. In addition, these parameters can additionally alter chemical compounds by inducing their degradation, producing thereafter other metabolites. Understanding the combined effects of chemicals and environmental parameters is absolutely necessary for an adequate prediction of risk in aquatic environments. According to this scenario, this work aims at studying the combined toxicity of UVR and three xenobiotics: the biocide triclosan (TCS), the metal chromium (as potassium dichromate, PD) and the fungicide prochloraz (PCZ). To achieve this goal zebrafish (Danio rerio) embryos (3hr post fertilization (hpf)) were exposed to several concentrations of each chemical combined with different UV intensities; mortality and eggs were recorded every 24hr for the all test duration (96hr). Results showed different response patterns depending on the toxicant, stress levels and duration of exposure. The combination of UVR and TCS indicated a dose ratio deviation where synergism was observed when UVR was the dominant stressor (day 2). The combination of UVR and PD presented a dose level dependency at day 3 indicating antagonism at low stress levels, changing with time where at day 4, a dose ratio deviation showed statistically that synergism occurred at higher PD concentrations. Finally, UVR combined with PCZ indicated a dose ratio at day 3 and dose level deviation at day 4 of exposure, suggesting a synergistic response when PCZ is the dominant stressor in the combination. The obtained results in this study highlighted the importance of taking into account the possible interaction of stressors and time of exposure to better predict environmental risk.

For more Interactions (Complete) data for POTASSIUM DICHROMATE (18 total), please visit the HSDB record page.

Health EffectsHexavalent chromium is a known carcinogen. Chronic inhalation especially has been linked to lung cancer. Hexavalent chromium has also been know to cause reproductive and developmental defects. (A12)
Ecotoxicity Values · 5 items

LC50; Species: /Coturnix japonica/ (Japanese quail) 14 days old; oral 4400 ppm for 5 days

LC50; Species: /Anas platyrhynchos/ (Mallard duck) 10 days old; oral >5000 ppm for 5 days (no mortality to 5000 ppm)

LC50; Species: Carassius auratus (goldfish); Conditions: flow through, water hardness of 220 mg/L as calcium carbonate; Concentration: 90,000-135,000 ug/L as chromium (range), measured method

LC50; Species: Macrobrachium lamarrei (freshwater prawn); Concentration: 5.44, 3.69, 2.47, and 1.84 mg/L for 24, 48, 72, and 96 hr, respectively /Conditions of bioassay not specified in source examined/

For more Ecotoxicity Values (Complete) data for POTASSIUM DICHROMATE (42 total), please visit the HSDB record page.

Adverse EffectsOccupational hepatotoxin - Secondary hepatotoxins: the potential for toxic effect in the occupational setting is based on cases of poisoning by human ingestion or animal experimentation.
Exposure Routes · 2 items

The substance can be absorbed into the body by inhalation of its aerosol, through the skin and by ingestion.

Inhalation (L16) ; oral (L16) ; dermal (L16)

Regulatory information

RCRA Requirements · 1 item

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/

FIFRA Requirements · 1 item

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. Potassium dichromate is found on List A, which contains most food use pesticides and consists of the 194 chemical cases (or 350 individual active ingredients) for which EPA issued registration standards prior to FIFRA, as amended in 1988. Case No: 0132; Pesticide type: Fungicide (Wood preservative); Registration Standard Date: 06/01/88, 09/10/86; Case Status: OPP is reviewing data from the pesticide's producers regarding its human health and/or environmental effects, or OPP is determining the pesticide's eligibility for reregistration and developing the Reregistration Eligibility Decision (RED) document.; Active ingredient (AI): Potassium dichromate; Data Call-in (DCI) Date(s): 01/31/94; AI Status: The producers of the pesticide has made commitments to conduct the studies and pay the fees required for reregistration, and are meeting those commitments in a timely manner.

Atmospheric Standards · 2 items

... 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/

Listed as a hazardous air pollutant (HAP) generally known or suspected to cause serious health problems. The Clean Air Act, as amended in 1990, directs EPA to set standards requiring major sources to sharply reduce routine emissions of toxic pollutants. EPA is required to establish and phase in specific performance based standards for all air emission sources that emit one or more of the listed pollutants. Chromium compounds is included on this list. /Chromium compounds/

CERCLA Reportable Quantities · 1 item

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).

Clean Water Act Requirements · 2 items

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.

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/

State Drinking Water Standards(CA) CALIFORNIA 10 ug/L /Hexavalent Chromium/

Chemistry & industry

Pharmacology

Metabolism/Metabolites · 1 item

Chromium is absorbed from oral, inhalation, or dermal exposure and distributes to nearly all tissues, with the highest concentrations found in kidney and liver. Bone is also a major storage site and may contribute to long-term retention. Hexavalent chromium's similarity to sulfate and chromate allow it to be transported into cells via sulfate transport mechanisms. Inside the cell, hexavalent chromium is reduced first to pentavalent chromium, then to trivalent chromium by many substances including ascorbate, glutathione, and nicotinamide adenine dinucleotide. Chromium is almost entirely excreted with the urine. (A12, L16)

MeSH Pharmacological Classification · 2 items

Strong alkaline chemicals that destroy soft body tissues resulting in a deep, penetrating type of burn, in contrast to corrosives, that result in a more superficial type of damage via chemical means or inflammation. Caustics are usually hydroxides of light metals. SODIUM HYDROXIDE and potassium hydroxide are the most widely used caustic agents in industry. Medically, they have been used externally to remove diseased or dead tissues and destroy warts and small tumors. The accidental ingestion of products (household and industrial) containing caustic ingredients results in thousands of injuries per year.

Chemicals and substances that impart color including soluble dyes and insoluble pigments. They are used in INKS; PAINTS; and as INDICATORS AND REAGENTS.

Absorption, Distribution and Excretion · 2 items

The acute and subacute toxicities of several Cr(III) and Cr(VI) compounds (chromium(3+) chloride, chromium(3+) nitrate, chromium(3+) sulfate, chromium trioxide, potassium dichromate) were determined in NZC and (CxO) mice injected ip. The distal median lethal doses (> 10 days after treatment) averaged (17.9 + or - 1.8) X 10(-6) g chromium/g body wt regardless of the oxidation state of the Cr compound injected (chromium(3+) sulfate may be an exception), but acute toxicity (3 days) was much greater with Cr(VI) compounds. Acid digests of entire male mice that were administered ip 1/6 of the distal LD50, either once or repeatedly at weekly intervals, were analyzed to determine the whole body persistence and clearance kinetics of Cr. Mice dosed once with Cr(III) retained 6.5 times more chromium at 21 days than mice treated with Cr(VI). When Cr(III) was given at weekly intervals mice accumulated 6 times more Cr by 8 wk than Cr(VI)-treated mice, though only the latter showed symptoms of chromic toxicity. Whole body Cr concentrations continued to rise with further Cr(III) treatments, but slowly declined with Cr(VI). Analyses of fecal and urinary excretion confirmed that most of the urinary Cr excretion from Cr(VI)-treated animals was much faster in both urine and feces than from mice given Cr(III). The differential storage and clearance kinetics of Cr(III) and Cr(VI) compounds may be significant in experimental Cr carcinogenesis studies and in the toxicology of Cr in workers exposed industrially to potentially carcinogenic chromium-containing dusts or aerosols.

The interaction of potassium dichromate (Cr(VI)) with bovine serum albumin (BSA) was investigated by fluorescence, synchronous fluorescence, resonance light scattering (RLS), ultraviolet-visible absorption, and circular dichroism (CD) spectroscopies under simulated physiological conditions. The experimental results showed that Cr(VI) could quench the intrinsic fluorescence of BSA following a static quenching process, which indicates the formation of a Cr(VI)-BSA complex. The binding constant (KA) and binding site (n) were measured at different temperatures. The spectroscopic results also revealed that the binding of Cr(VI) to BSA can lead to the loosening of the protein conformation and can change the microenvironment and skeleton of BSA.

Uses & manufacturing

Uses · 6 items

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]

Battery Manufacturing [Category: Industry]

Textile arts [Category: Hobbies]

For potassium dichromate (USEPA/OPP Pesticide Code: 068302) there are 0 labels match. /SRP: Not registered for current use in the U.S., but approved pesticide uses may change periodically and so federal, state and local authorities must be consulted for currently approved uses./

In tanning leather, dyeing, painting, printing, 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 solubility is advantageous. Pharmaceutic aid (oxidizing agent). Redox reagent.

Oxidizing agent (chemicals, dyes, intermediates); analytical reagent; brass pickling compositions; electroplating; ... explosives; ... textiles; dyeing and printing; chrome glues and adhesives; ... poison fly paper; process engraving and lithography; synthetic perfumes; chrome alum manufacture; ... alloys; ceramic products; depolarizer in dry cell batteries; bleaching fats and waxes.

Methods of Manufacturing · 2 items

In the USA it is usually prepared by the reaction of potassium chloride on sodium dichromate ... In Germany it is obtained from potassium chromate produced by roasting the chrome ore with potassium hydroxide.

Potassium dichromate is produced industrially by roasting chrome ore with potassium carbonate, or, preferably, by reacting sodium dichromate with potassium chloride.

Formulations/Preparations · 4 items

Technical granular form: Potassium dichromate, 99.9%; Chloride, 0.03%; Insolubles, 0.007%; Sulfate, 0.006%.

Grade: Commercial; highest purity; highest purity fused; reagent.

Iopezite

Potassium dichromate is available at a purity of 99.8%.

General Manufacturing Information · 2 items

Chromic acid (H2Cr2O7), potassium salt (1:2): ACTIVE

Potassium dichromate has largely been supplanted by the cheaper sodium dichromate but is still used whenever its advantage of being nonhygroscopic is important, for example, in the match, firework, film, and photographic industries.

Related reactions

59 records

Linked notes

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