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chromium dioxide

chromium dioxide structure

chromium dioxide 

structure
  • CAS No:

    12018-01-8

  • Formula:

    CrO2

  • Chemical Name:

    chromium dioxide

  • Synonyms:

    MAGTRIEVE(TM);Magtrieve? chromium dioxide;accroxc;accroxr;Chromium oxide (CrO2);chromium(iv)dioxide;chromiumdioxide;chromiumdioxide(cro2)

  • Categories:

    Inorganic Chemistry  >  Oxides and Peroxides

Description

BROWN-BLACK POWDER.


BROWN-BLACK POWDER.


dark brown or black powder(s); tetr; used in magnetic tapes [KIR78]; ferromagnetic; rutile structure [MER06]

chromium dioxide Basic Attributes

83.99

83.930344

234-630-4

1310

TSCA listed

DTXSID7065174

brown-black tetragonal powder

Characteristics

34.14000

Chromium dioxide [12018-01-8], chromium(IV)oxide, CrO2, is a ferromagnetic material with a specific saturation magnetization Ms/ of 132 A m2 kg1 at 0 K, corresponding to the spin of two unpaired electrons per Cr4+ ion. TheMs/n value of CrO2 at room temperature is ca. 100 A m2 kg1; CrO2 magnetic pigments reach values of 77–92 A m2 kg1. The material crystallizes with a tetragonal rutile lattice in the form of small needles, which have the desired magnetic shape anisotropy. The morphology of the particles can be varied with several dopants, particularly antimony and tellurium. The coercive field strength can be controlled between ca. 30 and 75 kA m1 (in addition to shape) by doping with transition metal ions, which modify the magneto-crystalline anisotropy of the material; the Fe3+ ion being industrially important.

-0.23760

black tetrahedral ferromagnetic crystals

4.85 g/mL at 25 °C(lit.)

>375 °C (dec.)(lit.)

decomposes to Cr2O3℃ [KIR78]

insoluble H2O, soluble acids giving Cr+++and dichromate [KIR78]

Keep container tightly closed in a dry and well-ventilated place.

Black semiconducting material; acicular crystals having strong magnetic properties|At room temperature and normal pressure chromium dioxide is metastable; when heated to temperatures above 350 °C, it decomposes into chromium(III) oxide and oxygen. Chromium dioxide has an oxidizing action on reactive organic compounds.

Safety Information

NONH for all modes of transport

3

Xi

26-36

GB6400000

Xi

Stable under recommended storage conditions.|Metastable in air

P305 + P351 + P338

36

Generators of waste (equal to or greater than 100 kg/mo) containing this contaminant, EPA hazardous waste number D007, must conform with USEPA regulations in storage, transportation, treatment and disposal of waste. /Chromium/|Product: Offer surplus and non-recyclable solutions to a licensed disposal company; Contaminated packaging: Dispose of as unused product.|Wastewater treatment sludge from the production of chrome green pigments is a poor candidate for incineration. /Chrome green pigments/|SRP: Wastewater from contaminant suppression, cleaning of protective clothing/equipment, or contaminated sites should be contained and evaluated for subject chemical or decomposition product concentrations. Concentrations shall be lower than applicable environmental discharge or disposal criteria. Alternatively, pretreatment and/or discharge to a permitted wastewater treatment facility is acceptable only after review by the governing authority and assurance that "pass through" violations will not occur. Due consideration shall be given to remediation worker exposure (inhalation, dermal and ingestion) as well as fate during treatment, transfer and disposal. If it is not practicable to manage the chemical in this fashion, it must be evaluated in accordance with EPA 40 CFR Part 261, specifically Subpart B, in order to determine the appropriate local, state and federal requirements for disposal.|For more Disposal Methods (Complete) data for CHROMIUM DIOXIDE (9 total), please visit the HSDB record page.

Incompatible materials: Strong oxidizing agents

DHHS/ATSDR; Toxicological profile for chromium (September 2012).[DHHS/ATSDR; Toxicological profile for chromium (September 2012); Available from, as of February 8, 2016: ww.atsdr.cdc.gov/toxprofiles/tp7.pdf]

|Warning|H319 (100%): Causes serious eye irritation [Warning Serious eye damage/eye irritation]|P264, P280, P305+P351+P338, and P337+P313|Aggregated GHS information provided by 70 companies from 2 notifications to the ECHA C&L Inventory.|H319: Causes serious eye irritation [Warning Serious eye damage/eye irritation]

Eye/face protection: Safety glasses with side-shields conforming to EN166. Use equipment for eye protection tested and approved under appropriate government standards such as NIOSH (US) or EN 166(EU).|Skin protection: Handle with gloves.|Body Protection: Impervious clothing. The type of protective equipment must be selected according to the concentration and amount of the dangerous substance at the specific workplace.|Respiratory protection: For nuisance exposures use type P95 (US) or type P1 (EU EN 143) particle respirator. For higher level protection use type OV/AG/P99 (US) or type ABEK-P2 (EU EN 143) respirator cartridges. Use respirators and components tested and approved under appropriate government standards such as NIOSH (US) or CEN (EU).

Suitable extinguishing media: Use water spray, alcohol-resistant foam, dry chemical or carbon dioxide.|Advice for firefighters: Wear self contained breathing apparatus for fire fighting if necessary.

ACCIDENTAL RELEASE MEASURES: Personal precautions, protective equipment and emergency procedures: Use personal protective equipment. Avoid dust formation. Avoid breathing vapors, mist or gas. Ensure adequate ventilation. Avoid breathing dust; Environmental precautions: Do not let product enter drains; Methods and materials for containment and cleaning up: Pick up and arrange disposal without creating dust. Sweep up and shovel. Keep in suitable, closed containers for disposal.

ACCIDENTAL RELEASE MEASURES: Personal precautions, protective equipment and emergency procedures: Use personal protective equipment. Avoid dust formation. Avoid breathing vapors, mist or gas. Ensure adequate ventilation. Avoid breathing dust; Environmental precautions: Do not let product enter drains.|Precautions for safe handling: Avoid contact with skin and eyes. Avoid formation of dust and aerosols. Provide appropriate exhaust ventilation at places where dust is formed. Normal measures for preventive fire protection.|Appropriate engineering controls: Handle in accordance with good industrial hygiene and safety practice. Wash hands before breaks and at the end of workday.|Gloves must be inspected prior to use. Use proper glove removal technique (without touching glove's outer surface) to avoid skin contact with this product. Dispose of contaminated gloves after use in accordance with applicable laws and good laboratory practices. Wash and dry hands.|SRP: Local exhaust ventilation should be applied wherever there is an incidence of point source emissions or dispersion of regulated contaminants in the work area. Ventilation control of the contaminant as close to its point of generation is both the most economical and safest method to minimize personnel exposure to airborne contaminants. Ensure that the local ventilation moves the contaminant away from the worker.

Permissible Exposure Limit: Table Z-1 8-hr Time Weighted Avg: 1 mg/cu m. /Chromium metal and insoluble salts, as Cr/|Permissible Exposure Limit: Table Z-1 8-hr Time Weighted Avg: 0.5 mg/cu m. /Chromium(II) compounds, as Cr/|Permissible Exposure Limit: Table Z-1 8-hr Time Weighted Avg: 0.5 mg/cu m. /Chromium(III) compounds, as Cr/|Permissible Exposure Limit: Table Z-2 Acceptable Ceiling Concentration: 1 mg/10 cu m. /Chromic acid and chromates (as CrO3)/

Recommended Exposure Limit: 8-hour Time-Weighted Average: 0.5 mg Cr/cu m. /Chromium metal, chromium(II) and chromium(III) compounds/|Recommended Exposure Limit: 8-hour Time-Weighted Average: 0.0002 mg Cr(VI)/cu m. NIOSH considers all Cr(VI) compounds (including chromic acid, tert-butyl chromate, zinc chromate, and chromyl chloride) to be potential occupational carcinogens. /All hexavalent chromium (Cr(VI) compounds/|NIOSH usually recommends that occupational exposures to carcinogens be limited to the lowest feasible concentration. /Chromic acid and chromates/

Personal protection: particulate filter respirator adapted to the airborne concentration of the substance. Vacuum spilled material with specialist equipment. Sweep spilled substance into covered containers. If appropriate, moisten first to prevent dusting.

Evaporation at 20 °C is negligible; a harmful concentration of airborne particles can, however, be reached quickly.

Repeated or prolonged contact with skin may cause dermatitis. Repeated or prolonged inhalation may cause effects on the lungs. This may result in fibrosis.

PREVENT DISPERSION OF DUST!

Use local exhaust or breathing protection.

Protective gloves.

Wear safety spectacles.

... 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/

D007; A waste containing chromium may or may not be characterized as a hazardous waste following testing by the Toxicity Characteristic Leaching Procedure as prescribed by the Resource Conservation and Recovery Act (RCRA) regulations. /Chromium/

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/

Toxicity

IDENTIFICATION AND USE: Chromium dioxide is a brown-black tetragonal powder. It is used in magnetic recording tapes; as catalyst. Magnetic particles used as solid support in immunoassay. HUMAN EXPOSURE AND TOXICITY: The clinical and hygienic studies performed at the antimonite ore extraction mines in Yakutia revealed that the workers were exposed to high concentrations of polymetallic dusts, containing chromium dioxide, antimony, arsenic and their compounds. Eleven percent of the workers exhibited dust bronchitis, changes in the blood, and immune reactivity indices. A patient with progressive systemic sclerosis and high levels of serum IgE developed multiple papules at/on an area of non-sclerotic skin. Histologic examination of the papule revealed the typical features of scleroderma. For several years, the patient had been working on polishing watches with an abrasive agent composed mainly of aluminum, chromium dioxide, and silica. ANIMAL STUDIES: Rats were exposed by inhalation to chromium dioxide (CrO2) dust at design concentrations of 0, 0.5 (stabilized and unstabilized, respectively) or 25 mg per cu m (stabilized) for 6 hr day-1, 5 days week-1 for 2 years. No dust-exposure-related pathological changes were observed, other than lung lesions, in all exposed rats. There were no significant differences in pulmonary response between unstabilized and stabilized CrO2 at the 0.5 mg per cu m exposure level. The lungs showed minute dust deposition in the alveoli adjacent to the alveolar ducts, but maintained an intact general architecture. The pulmonary responses satisfied the biological criteria for a nuisance dust. At 25 mg per cu m, dust deposition was sharply confined to the alveoli in the alveolar duct region. Alveolar walls enclosing dust-laden macrophage (dust cell) aggregates were thickened with hyperplastic Type II pneumocytes and slightly collagenized fibrosis. Alveoli adjacent to the terminal bronchioles were lined with bronchiolar epithelium (alveolar bronchiolarization). In addition, lungs showed foamy macrophage response, cholesterol granulomas, alveolar proteinosis, and minute fibrotic pleurisy. These pulmonary lesions occurred predominantly in female rats. Of 108 female rats, six developed keratin cysts and two had cystic keratinizing squamous cell carcinoma (CKSCC). None of 106 male rats had either a keratin cyst or a CKSCC. The lung tumors developed from metaplastic squamous cells in the areas of alveolar bronchiolarization in the alveolar duct region. The lung tumors were well differentiated and devoid of characteristics of true malignancy. The CKSCC is an experimentally-induced, unique tumor type and is different from the type of spontaneous lung tumor seen in man or animals.

Chromium dioxide does not occur in nature.

NIOSH (NOES Survey 1981-1983) has statistically estimated that 1,023 workers (749 of these are female) were potentially exposed to chromium dioxide in the US(1).

Drug Information

Rinse and then wash skin with water and soap.

/SRP:/ Immediate first aid: Ensure that adequate decontamination has been carried out. If patient is not breathing, start artificial respiration, preferably with a demand-valve resuscitator, bag-valve-mask device, or pocket mask, as trained. Perform CPR as necessary. Immediately flush contaminated eyes with gently flowing water. Do not induce vomiting. If vomiting occurs, lean patient forward or place on left side (head-down position, if possible) to maintain an open airway and prevent aspiration. Keep patient quiet and maintain normal body temperature. Obtain medical attention. /Inorganic acids and related compounds/|/SRP:/ Basic treatment: Establish a patent airway (oropharyngeal or nasopharyngeal airway, if needed). Suction if necessary. Watch for signs of respiratory insufficiency and assist respirations if needed. Administer oxygen by nonrebreather mask at 10 to 15 L/min. Monitor for pulmonary edema and treat if necessary ... . Monitor for shock and treat if necessary ... . For eye contamination, flush eyes immediately with water. Irrigate each eye continuously with 0.9% saline (NS) during transport ... . Do not use emetics. Activated charcoal is not effective. For ingestion, rinse mouth and administer 5 mL/kg up to 200 mL of water for dilution if the patient can swallow, has a strong gag reflex, and does not drool ... . Do not attempt to neutralize because of exothermic reaction. Cover skin burns with dry, sterile dressings after decontamination ... . /Inorganic acids and related compounds/|/SRP:/ Advanced treatment: Consider orotracheal or nasotracheal intubation for airway control in the patient who is unconscious, has severe pulmonary edema, or is in severe respiratory distress. Early intubation, at the first sign of upper airway obstruction, may be necessary. Positive-pressure ventilation techniques with a bag valve mask device may be beneficial. Consider drug therapy for pulmonary edema ... . Consider administering a beta agonist such as albuterol for severe bronchospasm ... . Monitor cardiac rhythm and treat arrhythmias as necessary ... . Start IV administration of D5W /SRP: "To keep open", minimal flow rate/. Use 0.9% saline (NS) or lactated Ringer's(LR) if signs of hypovolemia are present. For hypotension with signs of hypovolemia, administer fluid cautiously. Consider vasopressors if patient is hypotensive with a normal fluid volume. Watch for signs of fluid overload ... . Use proparacaine hydrochloride to assist eye irrigation ... . /Inorganic acids and related compounds/

/SIGNS AND SYMPTOMS/ The clinical and hygienic studies performed at the antimonite ore extraction mines in Yakutia revealed that the workers were exposed to high concentrations of polymetallic dusts, containing chromium dioxide, antimony, arsenic and their compounds. Eleven percent of the workers exhibited dust bronchitis, changes in the blood and immune reactivity indices which were due to reactions of adaptation to the Far North climatic conditions and the occupational factors' toxic effects.|/CASE REPORTS/ A patient with progressive systemic sclerosis and high levels of serum IgE developed multiple papules at/on an area of non-sclerotic skin. Histologic examination of the papule revealed the typical features of scleroderma. For several years, the patient had been working on polishing watches with an abrasive agent composed mainly of aluminum, chromium dioxide, and silica. An association of the abrasive agent, especially of the silica component, with the scleroderma was circumstantially suspected.|/EPIDEMIOLOGY STUDIES/ Twenty-six workers were studied (9 chrome-platers exposed to chromium dioxide and 17 workers exposed to metallic chromium dust) in order to investigate the macroscopic and cytological changes of the nasal mucosa due to exposure to water-soluble hexavalent chromium or to metallic chromium dust in the electroplating industry and the role of different valencies in the onset of nasal disease. Experimental and epidemiological data have shown that hexavalent chromium, which has strong oxidative power, induces more noticeable toxic effects on tissues and mucous membranes than other compounds. The correlation between the degree of local toxic effects and the chemical state of chromium was demonstrated in both the macro- and the microscopic investigations and in particular in the cytological examinations: cases of atypia were found only in workers exposed to hexavalent chromium. Evidence of atypia raises the question of whether hexavalent chromium may act as a carcinogenic agent on the rhinosinusal mucosa. For this reason, the introduction of cytological nasal examination in health surveillance programs for this category of workers acquires considerable importance. Sample collection from the nasal mucosa by brushing is the method of choice since it is simple, non-invasive and gives good diagnostic results.

The substance can be absorbed into the body by inhalation.

Cough.


Redness.

chromium dioxide Use and Manufacturing

Methods of Manufacturing

Mix 5.68 kg of chromic anhydride and 2.25 L of water, stir for 10 min, add 11.94 g of antimony trioxide, γ-Fe2O323.88 g and 2.88 kg of chromium trioxide, and after stirring for 20 min, add the above mixture to the autoclave. After reacting at 270°C and a pressure of 45×103kPa for 15h, the finished chromium dioxide product was prepared.

Uses

In magnetic recording tapes; as catalyst.


Chromium dioxide is used exclusively for magnetic recording media. It may also be used in combination with cobalt-modified iron oxides in the production of magnetic recording media. The world consumption of CrO2 is decreasing continuously as compact disc and digital videodisc are taking over the audio and video market. The sole producer is DuPont.In the course of the development of pigments for magnetic information storage, CrO2 was the first widely used pigment material that gave a higher recording density than ã-Fe2O3. In the field of audio recording this led to the IEC II standard or “chrome position”.


Facilitates high yield aromatization of Hantzsch 1,4-dihydropyridines to the corresponding pyridines.

Production

The conversion of an intimate mixture of Cr(III) and Cr(VI) compounds into CrO2 under hydrothermal conditions has been developed into an industrial process in autoclaves at ca. 350 °C and 300 bar.Pure CrO2 slowly disproportionates in the presence of water. The CrO2 crystal surface of commercial pigments is therefore topotactically converted to â-CrOOH, which serves as a protection layer. In the absence of moisture, CrO2 is stable up to ca. 400 °C, above this temperature it decomposes to form Cr2O3 and oxygen.

Magtrieve

Chromium oxide (CrO2): ACTIVE|... Use is in high-energy magnetic tapes. These tapes are reported to give improved fidelity at lower speeds than conventional magnetic tapes based on acicular ferric oxide.

Computed Properties

Molecular Weight:88.027
Hydrogen Bond Donor Count:2
Hydrogen Bond Acceptor Count:2
Exact Mass:87.961634
Monoisotopic Mass:87.961634
Topological Polar Surface Area:2
Heavy Atom Count:3
Covalently-Bonded Unit Count:3
Compound Is Canonicalized:Yes

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