7738-94-5 Usage
Chemical Description
Chromic acid is a strong oxidizing agent that is used in the oxidation of organic compounds.
Description
Chromic acid, CrO3, is composed of dark, purplish-red, odorless crystals that are soluble in water. The specific gravity is 2.7, which is heavier than water. It is a powerful oxidizing agent and may explode on contact with organic materials. Chromic acid is a poison, corrosive to the skin, and has a TLV of 0.05 mg/m3 of air. Chromic acid is a known human carcinogen. The four-digit UN identification number is 1463. The NFPA 704 designation is health 3, flammability 0, and reactivity 1. The white section at the bottom of the 704 diamond has an “oxy” prefix, indicating that it is an oxidizer.
Chemical Properties
Chromic acid is a dark purplish-red odorless flakes or crystalline powder
Uses
Chemicals (chromates, oxidizing agents, catalysts), chromium-plating intermediate, medicine
(caustic), process engraving, anodizing, ceramic
glazes, colored glass, metal cleaning, inks, tanning,
paints, textile mordant, etchant for plastics.
Definition
Different sources of media describe the Definition of 7738-94-5 differently. You can refer to the following data:
1. The name is in common use, although the true
chromic acid, H2CrO4, exists only in solution.
2. chromic acid: A hypothetical acid,H2CrO4, known only in chromatesalts.
General Description
Chromic acid is a dark purplish red solid, exists only in solution. The hydrate of chromiumoxide, it is used in electroplating baths. Chromic acid is soluble in water with the release of heat. The material itself is noncombustible but Chromic acid will accelerate the burning of combustible materials. Its solution is corrosive to metals and tissue.
Air & Water Reactions
Water soluble.
Reactivity Profile
A very powerful oxidizing agent, confirmed human carcinogen. Upon contact with reducing reagents Chromic acid can cause a violent explosion, in contact with organic matter Chromic acid may cause a violent oxidation leading to ignition. Dangerously reactive with acetone, alcohols, alkali metals (sodium, potassium), ammonia, arsenic, dimethylformamide, hydrogen sulfide, phosphorus, peroxyformic acid, pyridine, selenium, sulfur, and many other chemicals [Sax, 9th ed., 1996, p. 852]. When mixed with sulfuric acid for glass cleaning operations, used solution in closed bottle may explode due to internal pressure of carbon dioxide arising from contamination by carbon compounds [Bryson, W. R., Chem. Brit., 1975, 11, p. 377].
Hazard
A human carcinogen. A poison. Corrosive
to skin. Powerful oxidizing agent, may explode on
contact with reducing agents, may ignite on contact with organic materials. Upper respiratory tract
irritant.
Health Hazard
Very irritating to eyes and respiratory tract. Ingestion causes severe gastrointestinal symptoms. Contact with eyes or skin causes burns; prolonged contact produces dermatitis (``chrome sores'').
Safety Profile
Confirmed human
carcinogen. Poison by subcutaneous route.
Mutation data reported. A powerful
oxidzer. A powerful irritant of skin, eyes,
and mucous membranes. Can cause a
dermatitis, bronchoasthma, “chrome holes,”
damage to the eyes. Dangerously reactive.
Incompatible with acetic acid, acetic
anhydride, tetrahydronaphthalene, acetone,
alcohols, alkali metals, ammonia, arsenic,
bromine penta fluoride, butyric acid, n,ndimethylformamide, hydrogen sulfide,
peroxyformic acid, phosphorus, potassium
hexacyanoferrate, pyridme, selenium
Potential Exposure
n chromium plating; medicine, ceramic glazers, and paints.
Shipping
UN1463 Chromium trioxide, anhydrous, Hazard Class: 5.1; Labels: 5.1-Oxidizer, 6.1-Poisonous materials, 8-Corrosive material. UN1755 (solution) Chromic acid, solid, Hazard class: 8; Labels: 8-Corrosive material.
Incompatibilities
A strong oxidizer. Aqueous solution is strongly acidic. Reacts with acetic acid, acetic anhydride, acetone, anthracene, chromous sulfide; diethyl ether; dimethyl formamide; ethanol, hydrogen sulfide; methanol, naphthalene, camphor, glycerol, potassium ferricyanide, pyridine, turpentine, combustibles; organics, and other easily oxidized materials (such as paper, wood, sulfur, aluminum, and plastics). Attacks metals in presence of moisture
Waste Disposal
Chemical reduction to chromium(III) can be followed by land fill disposal of the sludge.
Check Digit Verification of cas no
The CAS Registry Mumber 7738-94-5 includes 7 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 4 digits, 7,7,3 and 8 respectively; the second part has 2 digits, 9 and 4 respectively.
Calculate Digit Verification of CAS Registry Number 7738-94:
(6*7)+(5*7)+(4*3)+(3*8)+(2*9)+(1*4)=135
135 % 10 = 5
So 7738-94-5 is a valid CAS Registry Number.
InChI:InChI=1/Cr.2H2O.2O/h;2*1H2;;/q+2;;;;/p-2/rCrH2O4/c2-1(3,4)5/h2-3H
7738-94-5Relevant articles and documents
UV-vis spectroscopic determination of the dissociation constant of bichromate from 160 to 400°C
Chlistunoff, Jerzy B.,Johnston, Keith P.
, p. 3993 - 4003 (1998)
On the basis of direct measurements by UV-vis spectroscopy, the dissociation constant of bichromate was found to decrease with temperature from 160 to 400°C. For fixed Cr(VI) and KOH concentrations, the molal concentration of HCrO4- initially increases with temperature but decreases again in the vicinity of water's critical point, where the density decreases substantially. The decrease in HCrO4- at high temperature and low density may be attributed to (K+)(CrO42-) ion pairs, to a high degree of electrostriction about CrO42-, which facilitates the reaction HCrO4- + OH- = CrO42- + H2O, and to ion activity coefficients.
Theoretical and experimental investigation of the thermochemistry of CrO2(OH)2(g)
Opila, Elizabeth J.,Myers, Dwight L.,Jacobson, Nathan S.,Nielsen, Ida M. B.,Johnson, Dereck F.,Olminsky, Jami K.,Allendor, Mark D.
, p. 1971 - 1980 (2007)
In this paper, we report the results of equilibrium pressure measurements designed to identify the volatile species in the Cr-O-H system and to resolve some of the discrepancies in existing experimental data. In addition, ab initio calculations were performed to lend confidence to a theoretical approach for predicting the thermochemistry of chromium-containing compounds. Equilibrium pressure data for CrO2(OH)2 were measured by the transpiration technique for the reaction 0.5Cr2O3(s) + 0.75O2(g) + H2O(g) = CrO2(OH)2(g) over a temperature range of 573 to 1173 K at 1 bar total pressure. Inductively coupled plasma atomic emission spectroscopy (ICP-AES) was used to analyze the condensate in order to quantify the concentration of Cr-containing volatile species. The resulting experimentally measured thermodynamic functions are compared to those computed using B3LYP density functional theory and the coupled-cluster singles and doubles method with a perturbative correction for connected triple substitutions [CCSD(T)].
Vaporisation of chromia in humid air
Gindorf,Singheiser,Hilpert
, p. 384 - 387 (2005)
Thermodynamic data for the computation of the vaporisation of Cr 2O3(s) in humid air show significant deviations between each other which lead to large differences in the computed partial pressures. The vaporisation of Cr2O3(s) in air with different humidities, p(H2O)=0.0007 bar to p(H2O)=0.3 bar, was, therefore, investigated at constant temperature of 1223 K by the vapour transpiration method. The results obtained were explained by the formation of CrO3(g) as major vapour species at low p(H2O) and the formation of CrO2(OH)2(g) as major vapour species at high p(H2O). The pressures evaluated are compared with those obtained by thermodynamic computations using different data bases.
Gemcitabine derivatives nanoparticles
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Page/Page column 4, (2009/05/28)
The invention concerns a 2′,2′-difluoro-2′-deoxycytidine derivative of general formula (I), wherein: R1, R2 and R3, identical or different, represent independently of one another, a hydrogen atom or an at least C18 hydrocarbon acyl radical and of such conformation that it is capable of providing the compound of general formula (I), a compacted form in a polar solvent medium, at least one of groups R1, R2 and R3 being other than a hydrogen atom.
PROCESS FOR THE PREPARATION OF METAL ACETYLACETONATES
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Page 13, (2008/06/13)
The present invention provides an improved, economical and environmmentally benign process for metal complexes of acetylacetone having the general formula, M(acac)n wherein M is a metal cation selected from the group consisting of Fe, Co, Ni, Cu, Zn, Al, Ca, Mg, Mo, Ru, Re, U, Th, Ce, Na, K, Rb, Cs, V, Cr, and Mn etc., n is an integer which corresponds to the electrovalence of M, are obtained by reacting the corresponding metal hydroxide, metal hydrated oxide or metal oxide with a stoichiometric amount of acetylacetone and separating the product.
