Ammonium dichromate

HCID 178808942CAS 77890-90-5

Basic information

Standard SMILES
[NH4+].[NH4+].[O]=[Cr](=[O])([O-])[O][Cr](=[O])(=[O])[O-]
InChIKey
JOSWYUNQBRPBDN-UHFFFAOYSA-P
Molecular formula
Cr2H2O7.2H3N
Average molar mass
252.07 g/mol

Overview

Ammonium dichromate is a bright orange red crystalline solid. It is readily ignited and burns producing a voluminous green residue. If heated in a closed container, the container may rupture due to the decomposition of the material. It may also act as a strong oxidizing agent if mixed with or contaminated with combustible material. It is soluble in water.

Names & identifiers

Preferred name
Ammonium dichromate
IUPAC
diazanium;oxido-(oxido(dioxo)chromio)oxy-dioxochromium
English name
Ammoniumdichromat
Molecular weight
0

Names & synonyms

AMMONIUM DICHROMATE7789-09-5Ammonium bichromateAmmonium dichromate(VI)AmmoniumdichromatAmmonium dichromate (VI)AmmoniumbichromaatAmmoniumdichromaatBichromate d'ammoniumDichromic acid, diammonium salt5J18BP595GAmmonio (bicromato di)
Show more names
Ammonio (dicromato di)Ammonium chromate ((NH4)2Cr2O7)Ammonium (dichromate d')Chromic acid (H2Cr2O7), diammonium saltDichromic acid (H2Cr2O7), diammonium saltDTXSID70872953Chromic acid (H2Cr2O7), ammonium salt (1:2)RefChem:112150

Database identifiers

CAS
77890-90-5
UNII
5J18BP595G
EC Number
232-143-1

Properties

Computed structural properties

Topological polar surface area
126 Ų
Hydrogen bond donors
2
Hydrogen bond acceptors
7
Rotatable bonds
0
Heavy atoms
11

Experimental & physicochemical properties

Chemical Classes · 2 items

Metals -> Chromium Compounds, Inorganic

Carcinogens

pH1% solution has pH of 3.95; 10% solution has pH of 3.45
OdorOdorless
Density · 5 items

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

2.155 g/cu cm at 25 °C

Non-hygroscopic; bulk density: 82 lb/cu ft; decomposes at about 180 °C; decomposes becomes self-sustaining at about 225 °C with spectacular swelling and evolution of heat and nitrogen, leaving Cr2O3. Heat of solution: -23.0 cal/g

2.15 g/cm³

2.155 @25 °C

Color/Form · 3 items

Bright orange-red monoclinic prisms

Solid at 15 °C and 1 atm

Orange needles

Solubility · 4 items

35.6 g/100 g water at 20 °C

In water (wt/wt): 15.16% at 0 °C; 26.67% at 20 °C; 36.99% at 40 °C; 46.14% at 60 °C; 54.20% at 80 °C; 60.89% at 100 °C

In water: 30.8 g/100 mL at 15 °C; 89 g/100 mL at 30 °C

Solubility in water, g/100ml at 20 °C: 36 (good)

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)

Danger

H272 (99.5%): May intensify fire; oxidizer [Danger Oxidizing liquids; Oxidizing solids]

P203, P210, P220, P233, P260, P261, P264, P264+P265, 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)

Hazard information

Regulatory Information · 6 items

Chemical: Chromic acid (H2Cr2O7), diammonium salt

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

Status: Cease Manufacture Update: 25-11-2010 https://echa.europa.eu/registration-dossier/-/registered-dossier/11854

Restricted substance: Ammonium dichromate

Substance: Ammonium dichromate

Chromic acid, diammonium salt: HSNO Approval: HSR001309 Approved with controls

Other Safety InformationIMAP assessments - Chromates and dichromates (soluble): Human health tier II assessment
DOT LabelOxidizer
Fire Hazards · 3 items

Special Hazards of Combustion Products: Greenish chromic oxide smoke may cause irritation of lungs and mucous membranes.

· These substances will accelerate burning when involved in a fire.

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

Fire PotentialModerately flammable.
Health Hazards · 2 items

Inhalation causes irritation or ulceration of the mucous membranes of the nose, throat or respiratory tract. Respiratory irritation can produce symptoms resembling those of asthma. Continuing irritation of the nose may lead to perforation of the nasal septum. External contact can cause eye irritation and conjunctivitis, irritation and ulceration of skin wounds, and rash or external ulcers. If ingested, irritates mucous membrane and causes vomiting. (USCG, 1999)

· Toxic by ingestion.

Safety & protection

Fire Fighting · 2 items

Excerpt from ERG Guide 141 [Oxidizers - Toxic]:

In case of fire in the surroundings, use appropriate extinguishing media. In case of fire: keep drums, etc., cool by spraying with water. Combat fire from a sheltered position.

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 .

Accidental Release Measures · 2 items

· CALL 911. Then call emergency response telephone number on shipping paper. If shipping paper not available or no answer, refer to appropriate telephone number listed on the inside back cover.

· Keep combustibles (wood, paper, oil, etc.) away from spilled material.

First Aid · 2 items

INHALATION: remove to clean air and summon medical attention.

General First Aid:

Safe StorageFireproof. Provision to contain effluent from fire extinguishing. Separated from organic solvents, combustible substances and reducing agents. Well closed. Store in an area without drain or sewer access.
Exposure Control and Personal Protection· Wear positive pressure self-contained breathing apparatus (SCBA).

Toxicology

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

IL50 /Inhibitory Level/ Eurasian Watermilfoil 1.9, 2.6, 8.0 and 9.5 ppm chromate for root weight, stem weight, root length, and stem length, respectively.

LC50; Species: Gambusia affinis (Western Mosquitofish); Conditions: freshwater, static, 18-20 °C, pH 5.7-7.4; Concentration: 223000 ug/L for 24 hr

LC50; Species: Gambusia affinis (Western Mosquitofish); Conditions: freshwater, static, 18-20 °C, pH 5.7-7.4; Concentration: 212000 ug/L for 48 hr

LC50; Species: Gambusia affinis (Western Mosquitofish); Conditions: freshwater, static, 18-20 °C, pH 5.7-7.4; Concentration: 136000 ug/L for 96 hr

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)

Toxicity Summary · 2 items

IDENTIFICATION AND USE: Ammonium dichromate is a solid at 15 °C and 1 atm, forming orange needles. It is not registered for current pesticide 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. It is used as a source of pure nitrogen (especially in the laboratory); in pyrotechnics (Vesuvius fire); in lithography and photo engraving; in special mordant, catalysts, and porcelain finished; intermediate in the manufacturing of pigments; of magnetic recording materials. It is also used as an oxidimentric standard in analytical chemistry. HUMAN EXPOSURE AND TOXICITY: Highly corrosive to skin and mucous membranes. If ingested, violent gastroenteritis with cholera-like stools, peripheral vascular collapse, vertigo, muscle cramps, coma, hemorrhagic diathesis, fever, liver damage & acute renal failure. Methemoglobinemia is probably secondary to intravascular hemolysis. It has been reported in the literature that the ingestion of ammonium dichromate by a child resulted in multiple-organ-system failure and death. Exchange transfusion and hemodialysis were ineffective in removing significant amounts of chromium or causing sustained clinical improvement. In an industrial setting, workers exposed to ammonium dichromate were clinically examined, and 9 of 18 showed dermatitis on the back of the hands and forearms. Three of these workers were transferred and were cured of their dermatitis. ANIMAL STUDIES: Experiments on rats showed inhalation of dust caused edema in perivascular and peribronchial tissue. Ammonium dichromate caused more pronounced changes than did sodium dichromate. ECOTOXICITY STUDIES: Strong irritant. Ammonium toxicity stems from unionized fraction. Chromium will usually be the allergen and limiting factor of the two; Highly toxic by ingestion or inhalation. Threshold concentration for fresh and saltwater fish: 0.05 ppm Cr(VI). Threshold concentration for free ammonia to fish: 0.5 ppm Cr(VI). Toxic to plants.

Hexavalent chromium's carcinogenic effects are caused by its metabolites, pentavalent and trivalent chromium. The DNA damage may be caused by hydroxyl radicals produced during reoxidation of pentavalent chromium by hydrogen peroxide molecules present in the cell. Trivalent chromium may also form complexes with peptides, proteins, and DNA, resulting in DNA-protein crosslinks, DNA strand breaks, DNA-DNA interstrand crosslinks, chromium-DNA adducts, chromosomal aberrations and alterations in cellular signaling pathways. It has been shown to induce carcinogenesis by overstimulating cellular regulatory pathways and increasing peroxide levels by activating certain mitogen-activated protein kinases. It can also cause transcriptional repression by cross-linking histone deacetylase 1-DNA methyltransferase 1 complexes to CYP1A1 promoter chromatin, inhibiting histone modification. Chromium may increase its own toxicity by modifying metal regulatory transcription factor 1, causing the inhibition of zinc-induced metallothionein transcription. (A12, L16, A34, A35, A36)

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/

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

Ammonium bichromate 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/
State Drinking Water Guidelines(ME) MAINE 35 ug/L /Cr VI)

Chemistry & industry

Pharmacology

Biological Half-LifeHalf-life in total human body: 616 days.
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)

Uses & manufacturing

Uses · 6 items

Used in photo engraving, dye mordants, pigments, oil purification, pickling, leather tanning, photography, process engraving, lithography, pyrotechnics, and glazes for porcelain and chinawares; [HSDB] Used as a nitrogen source and to make magnetic recording materials; [Merck Index] Used in pyrotechnics, wood preserving, and lithography; Regulated in Germany as an explosive, and it is distributed moist; [Ullmann]

Petroleum Production and Refining [Category: Industry]

Lithography printing [Category: Hobbies]

For Ammonium dichromate (USEPA/OPP Pesticide Code: 068305) 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./

Source of pure nitrogen (especially in the laboratory); in pyrotechnics (Vesuvius fire); in lithography and photo engraving; in special mordant, catalysts, and porcelain finishes; intermediate in the manufacture of pigments; of magnetic recording materials. Oxidimentric standard in analytical chemistry.

Mordant for dyeing, pigments, manufacturing of alizarin, chrome alum, oil purification, pickling, manufacture of catalysts, leather tanning, synthetic perfumes, photography, process engraving and lithography (sensitizer for photo- chemical insolubilization of albumin, etc.), chromic oxide, pyrotechnics.

Methods of Manufacturing · 3 items

Prepared from ammonium sulfate and sodium dichromate or by interaction of ammonia gas and chromic acid in solution.

Action of chromic acid on ammonium hydroxide with subsequent crystallization

Ammonium dichromate is prepared by reaction of sodium dichromate with ammonium chloride or, less frequently, ammonium sulfate.

Formulations/Preparations · 3 items

USEPA/OPP Pesticide Code 068305; Trade Names: Ammonio.

Crystal: Reagent, photolitho grades

Ammonium dichromate is available as analytical reagent-grade crystals (99.5%) and as purified-grade crystals and granules with the following impurities: chloride, 0.005% max; fixed alkalis (as sulfate), 0.1-0.2% max; insoluble matter, 0.005% max; and sulfate, 0.005% max.

General Manufacturing InformationChromic acid (H2Cr2O7), ammonium salt (1:2): ACTIVE

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