Ammonium dichromate

Ammonium dichromate Basic information
Description References
Product Name:Ammonium dichromate
Synonyms:chromicacid[h2cr2o7],diammoniumsalt;diammoniumdichromate;dichromicacid,diammoniumsalt;dichromicacid[h2cr2o7],diammoniumsalt;Dichromicaciddiammoniumsalt;AMMONIUM DICHROMATE;AMMONIUM PYROCHROMATE;AMMONIUM BICHROMATE
CAS:7789-09-5
MF:Cr2H8N2O7
MW:252.06
EINECS:232-143-1
Product Categories:Industrial/Fine Chemicals;Inorganics;Ammonium Salts;Chemical Synthesis;Chromates;Materials Science;Metal and Ceramic Science;NH3;Oxidation;Salts;Synthetic Reagents;Ultra-High Purity Materials
Mol File:7789-09-5.mol
Ammonium dichromate Structure
Ammonium dichromate Chemical Properties
Melting point 170 °C (dec.)(lit.)
density 2.150
vapor density 8.7 (vs air)
solubility H2O: 1 M at 20 °C, clear, colorless
form Solid
color Orange to red
OdorOdorless
PH Range3 - 4
Water Solubility 360 g/L (20 ºC)
Decomposition 170 °C
Merck 14,515
Exposure limitsACGIH: TWA 0.0002 mg/m3; STEL 0.0005 mg/m3 (Skin)
OSHA: Ceiling 0.1 mg/m3
NIOSH: IDLH 15 mg/m3; TWA 0.0002 mg/m3
Stability:Stability Strong oxidizer - contact with flammable materials may cause fire. Reactions carried out in closed vessels may lead to explosion. Incompatible with organic materials, strong reducing agents.
CAS DataBase Reference7789-09-5(CAS DataBase Reference)
EPA Substance Registry SystemAmmonium dichromate(VI) (7789-09-5)
Safety Information
Hazard Codes E,T+,N
Risk Statements 45-46-60-61-2-8-21-25-26-34-42/43-48/23-50/53
Safety Statements 53-45-60-61
RIDADR UN 1439 5.1/PG 2
WGK Germany 3
RTECS HX7650000
Autoignition Temperature218°C
TSCA Yes
HazardClass 5.1
PackingGroup II
HS Code 28415000
Hazardous Substances Data7789-09-5(Hazardous Substances Data)
ToxicityLDLo scu-gpg: 25 mg/kg EQSSDX 1,1,75
MSDS Information
ProviderLanguage
SigmaAldrich English
ACROS English
ALFA English
Ammonium dichromate Usage And Synthesis
DescriptionAmmonium dichromate is a salt consisting of ammonium ions and dichromate ions. It can be used as in pyrotechinics, photography as well as lithography. It can be used as a catalyst and a source of pure nitrogen in the laboratory. It can also be used as the mordant of dyeing pigment. It has application in the manufacturing of alizarin, chrome alum, leather tanning and oil purification. Moreover, it can be used for the production of phosphor raster of television screen through acting as the photoactive site. Finally, there are also reports using it for combustion synthesis of perovskite LnCrO3 powder and oxidation of hydroquinones, catechols and phenols.
ReferencesHavard, Jennifer M., et al. "Design of Photoresists with Reduced Environmental Impact. 1. Water-Soluble Resists Based on Photo- Cross-Linking of Poly(vinyl alcohol)." Plos One 8.4(1999):-.
Kingsley, J. J., and L. R. Pederson. "Combustion synthesis of perovskite LnCrO3 powders using ammonium dichromate." Materials Letters 18.1-2 (1993): 89-96.
Fischer, Alfred, and George N. Henderson. "Oxidation of hydroquinones, catechols, and phenols using ceric ammonium nitrate and ammonium dichromate coated on silica: an efficient and convenient preparation of quinones." Synthesis 1985.6/7 (1985): 641 -643.
Suzuki, S. "Determination of Chromium Atom Density on Deep UV Exposed Ammonium-Dichromated Gelatin Films with Ultraviolet Absorption Spectra." Journal of the Electrochemical Society135.10 (1988):2615-2620.

Chemical Propertiesbright orange-red crystals
Chemical PropertiesAmmonium dichromate is a combustible, orange-red crystalline solid which is used in solution.
OccurrenceBright orange-red monoclinic crystals; odorless; hygroscopic; decomposes at 180°C; density 2.115 g/cm3 at 25°C; readily dissolves in water (26.67 g/100 g at 20°C).
UsesAmmonium dichromate is used in photo engraving, dye mordant, pigments, pickling, photography, process engraving, lithography, pyrotechnics, glazes for porcelain and china wares. It acts as a catalyst and a source of nitrogen in the laboratory and as the photoactive site. It is also used in the preparation of alizarin and chrome alum. Further, it is used in leather and oil industry for tanning and purification respectively. It is involved in the production of the phosphor raster television screens and other devices.
UsesIt is used in oxidimetric standard.
UsesSource of pure nitrogen (esp 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.
UsesYellow needles made by chromic acid acting on ammonium hydroxide. The product is produced by crystallization. Ammonium dichromate was used interchangeably with potassium dichromate for sensitizing gelatin, albumen, gums, and other colloids that were used for pigment processes. Ammonium dichromate is more sensitive than the potassium alternative.
General DescriptionAmmonium dichromate is a bright orange red crystalline solid. Ammonium dichromate 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. Ammonium dichromate may also act as a strong oxidizing agent if mixed with or contaminated with combustible material. Ammonium dichromate is soluble in water.
Air & Water ReactionsWater soluble.
Reactivity ProfileAmmonium dichromate is an oxidizing reagent, Ammonium dichromate readily reacts with reducing materials, in large quantity Ammonium dichromate may produce a violent reaction. Direct exposure to heat or shock will explode it. When heated to decomposition Ammonium dichromate emits toxic fumes of ammonia and nitrogen oxides [Sax, 9th ed., 1996, p. 205].
HazardDusts and solutions are toxic, irritating to eyes and skin; dangerous fire risk. Strong oxidizing agent may explode in contact with organic materi- als. TLV: 0.05 mg(Cr)/m 3 ; Confirmed human car- cinogen.
Health HazardInhalation 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.
Safety ProfileConfirmed human carcinogen. Poison by inhalation, ingestion, skin contact, and subcutaneous routes. See also CHROMIUM COMPOUNDS. An unstable oxidizer. Moderately flammable; reacts with reducing agents.
Potential ExposureIt is used in dyeing, leather tanning and to make fireworks and chromic oxide; in lithography and photoengraving; in manufacture of special mordants and catalysts.
ShippingUN1439 Ammonium dichromate, Hazard Class: 5.1; Labels: 5.1-Oxidizer.
Purification MethodsIt crystallises from weak aqueous HCl (ca 1mL/g). It decomposes rapidly on heating. (Possible carcinogen and is POISONOUS)
IncompatibilitiesAn unstable oxidizer; freezing/melting point5(decomposes below MP) 180 C; decomposition becomes self-sustaining and violent at about 225 C. Contact with combustible, organic or other easily oxidized materials, strong acids; hydrazine and other reducing agents; alcohols, sodium nitrite may cause fire and explosions.
Waste DisposalConsult with environmental regulatory agencies for guidance on acceptable disposal practices. Generators of waste containing this contaminant (≥100 kg/mo) must conform with EPA regulations governing storage, transportation, treatment, and waste disposal. Add a large volume of a reductant solution (hypo, bisulfite or ferrous salt and acidify with sulfuric acid). Neutralize when reduction is complete and flush to sewer with large volume of water.
Ammonium dichromate Preparation Products And Raw materials
Raw materialsAmmonium chloride-->Chromium(VI) oxide-->Sodium dichromate dihydrate-->SODIUM DICHROMATE
Preparation ProductsAMMONIUM CHROMATE
Pyridinium dichromate Ammonium hydroxide Sodium dichromate dihydrate Bis(tetrabutylammonium) dichromate TETRAKIS(PYRIDINE)SILVER(I) DICHROMATE Ammonium formate Ammonium nitrate Ammonium dihydrogen phosphate 4-CARBOXYPYRIDINIUM DICHROMATE DICHROMATE Ammonium chloride QUINOLINIUM DICHROMATE Ammonium acetate Molybdic acid IMIDAZOLIUM DICHROMATE Ammonium carbonate Ammonium sulfate Ammonium dichromate

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