| Revision as of 13:32, 15 February 2012 editBeetstra (talk | contribs)Edit filter managers, Administrators172,055 edits Saving copy of the {{chembox}} taken from revid 476453549 of page Chromium_trioxide for the Chem/Drugbox validation project (updated: ''). |
Latest revision as of 21:54, 16 March 2024 edit Bernanke's Crossbow (talk | contribs)Extended confirmed users7,921 edits →Production, structure, and basic reactions: No {{clear}} |
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{{ambox | text = This page contains a copy of the infobox ({{tl|chembox}}) taken from revid of page ] with values updated to verified values.}} |
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{{Chembox |
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{{Chembox |
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| Watchedfields = changed |
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| Watchedfields = changed |
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| verifiedrevid = 451421780 |
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| verifiedrevid = 477001582 |
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| ImageFile = Chrom(VI)-oxid.jpg |
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| ImageFile = CrO3-from-xtal-1970-bulk-3D-balls.png |
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| ImageSize = 244 |
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| ImageSize = 200px |
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| ImageName = Ball-and-stick model of chromium trioxide |
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| ImageFile1 = CrO3-from-xtal-1970-bulk-3D-balls.png |
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| ImageCaption = {{legend|rgb(158, 176, 224)|], Cr}}{{legend|red|], O}} |
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| IUPACName = Chromium trioxide<br />Chromium(VI) oxide |
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| ImageFile1 = Chromium(VI) oxide.jpg |
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| OtherNames = Chromic anhydride, chromium(VI) oxide, chromic acid, anhydride, chromic acid (misnomer) |
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| ImageSize1 = 220px |
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| ImageName1 = Powder of chromium trioxide |
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| IUPACName = Chromium trioxide |
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| OtherNames = Chromic anhydride, Chromium(VI) oxide, Chromic acid (]) |
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| SystematicName = |
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| Section1 = {{Chembox Identifiers |
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| Section1 = {{Chembox Identifiers |
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| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}} |
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| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}} |
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| StdInChIKey = WGLPBDUCMAPZCE-UHFFFAOYSA-N |
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| StdInChIKey = WGLPBDUCMAPZCE-UHFFFAOYSA-N |
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| CASNo = 1333-82-0 |
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| CASNo = 1333-82-0 |
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| CASNo_Ref = {{cascite|correct|CAS}} |
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| CASNo_Ref = {{cascite|correct|CAS}} |
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| PubChem = 14915 |
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| PubChem = 14915 |
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| RTECS = GB6650000 |
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| RTECS = GB6650000 |
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}} |
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}} |
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| Section2 = {{Chembox Properties |
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| Section2 = {{Chembox Properties |
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| Cr = 1 |
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| Cr=1|O=3 |
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| Appearance = Dark red granular solid, ] |
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| O = 3 |
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| ExactMass = 99.9925256 |
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| Odor = Odorless |
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| Density = 2.7 g/cm<sup>3</sup> (20 °C)<ref name=crc /> |
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| Appearance = dark red granular solid <br> ] |
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| Odor = odorless |
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| Density = 2.70 g/cm<sup>3</sup> (20 °C) |
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| MeltingPtC = 197 |
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| MeltingPtC = 197 |
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| MeltingPt_ref = <ref name=crc /> |
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| BoilingPtC = 251 |
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| BoilingPtC = 250 |
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| Boiling_notes = decomposes |
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| BoilingPt_notes = <br> decomposes<ref name=crc /> |
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| Solubility = 61.7 g/100 mL (0 °C) <br /> 63 g/100 mL (25 °C) <br /> 67.45 g/100 mL (100 °C) |
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| Solubility = {{ubl|164.8 g/(100 mL) (0 °C)|169 g/(100 mL) (25 °C)<ref name=crc>{{CRC90}}</ref>|172.6 g/(100 mL) (40 °C)|198.1 g/(100 mL) (100 °C)<ref name=sioc>{{cite book|last1 = Seidell|first1 = Atherton|last2 = Linke|first2 = William F.|year = 1919|title = Solubilities of Inorganic and Organic Compounds|url = https://archive.org/details/solubilitiesino01seidgoog|publisher = D. Van Nostrand Company|edition = 2nd|page = }}</ref>}} |
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| SolubleOther = soluble in ], ], ], ], ], ] |
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| SolubleOther = Soluble in ], ], ], ], ] |
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| MagSus = +40·10<sup>−6</sup> cm<sup>3</sup>/mol<ref name=crc /> |
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}} |
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| Section4 = {{Chembox Hazards |
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| Section4 = {{Chembox Thermochemistry |
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| DeltaHf = −589.3 kJ/mol<ref name=pphoic>{{cite book|last = Pradyot|first = Patnaik|year = 2003|title = Handbook of Inorganic Chemicals|publisher = The McGraw-Hill Companies, Inc.|isbn = 0-07-049439-8}}</ref> |
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| ExternalMSDS = |
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| Entropy = 73.2 J/(mol·K)<ref name=chemister>{{cite web|url=http://chemister.ru/Database/properties-en.php?dbid=1&id=3425|title=chromium(VI) oxide|website=chemister.ru}}</ref> |
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| EUIndex = 024-001-00-0 |
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| EUClass = Oxidizer ('''O''')<br />]<br />]<br />Repr. Cat. 3<br />Very toxic ('''T+''')<br />Dangerous for the environment ('''N''') |
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| RPhrases = {{R45}}, {{R46}}, {{R9}}, {{R24/25}}, {{R26}}, {{R35}}, {{R42/43}}, {{R48/23}}, {{R62}}, {{R50/53}} |
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| SPhrases = {{S53}}, {{S45}}, {{S60}}, {{S61}} |
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| NFPA-H = 3 |
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| NFPA-F = 1 |
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| NFPA-R = 1 |
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| NFPA-O = OX |
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| LD50 = 80 mg/kg |
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}} |
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}} |
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| Section5 = {{Chembox Thermochemistry |
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| Section7 = {{Chembox Hazards |
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| ExternalSDS = |
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| DeltaHf = −579 kJ·mol<sup>−1</sup> |
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| GHSPictograms = {{GHS03}}{{GHS05}}{{GHS06}}{{GHS08}}{{GHS09}}<ref name="sigma">{{Sigma-Aldrich|id=675644|name=Chromium(VI) oxide|accessdate=2021-11-22}}</ref> |
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| Entropy = 72 J·mol<sup>−1</sup>·K<sup>−1</sup> |
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| GHSSignalWord = Danger |
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| HPhrases = {{H-phrases|271|301+311|314|317|330|334|335|340|350|361f|372|410}}<ref name="sigma" /> |
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| PPhrases = {{P-phrases|210|260|280|303+361+353|304+340+310|305+351+338}}<ref name="sigma" /> |
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| NFPA-H = 4 |
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| NFPA-F = 0 |
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| NFPA-R = 2 |
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| NFPA-S = OX |
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| NFPA_ref = <ref name = chemicalland21 /> |
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| LD50 = 80 mg/kg (rats, oral)<ref name = chemicalland21 /> |
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'''Chromium trioxide''' (also known as '''chromium(VI) oxide''' or '''chromic anhydride''') is an ] with the ] {{chem2|CrO3}}. It is the ] of ], and is sometimes marketed under the same name.<ref name = chemicalland21>{{cite web|url = http://www.chemicalland21.com/industrialchem/inorganic/CHROMIUM%20TRIOXIDE.htm|title = Chromium trioxide|publisher = AroKor Holdings Inc.|website = chemicalland21.com|access-date = 2014-06-15}}</ref> |
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This compound is a dark-purple ] under anhydrous conditions and bright orange when wet. The substance dissolves in water accompanied by hydrolysis.{{clarify|reason=the wording is arcane - what does it mean?|date=June 2023}} Millions of kilograms are produced annually, mainly for ].<ref name=ullmanns>{{Cite book | doi = 10.1002/14356007.a07_067| chapter = Chromium Compounds| title = Ullmann's Encyclopedia of Industrial Chemistry| year = 2000| last1 = Anger | first1 = G. | last2 = Halstenberg | first2 = J. | last3 = Hochgeschwender | first3 = K. | last4 = Scherhag | first4 = C. | last5 = Korallus | first5 = U. | last6 = Knopf | first6 = H. | last7 = Schmidt | first7 = P. | last8 = Ohlinger | first8 = M. | isbn = 3527306730}}</ref> Chromium trioxide is a powerful oxidiser, a ], and a ].<ref>{{cite journal | last1=Mamyrbaev | first1=Arstan Abdramanovich | last2=Dzharkenov | first2=Timur Agataevich | last3=Imangazina | first3=Zina Amangalievna | last4=Satybaldieva | first4=Umit Abulkhairovna | title=Mutagenic and carcinogenic actions of chromium and its compounds | journal=Environmental Health and Preventive Medicine | publisher=Springer Science and Business Media LLC | volume=20 | issue=3 | date=2015-04-16 | issn=1342-078X | doi=10.1007/s12199-015-0458-2 | pages=159–167| pmid=25877777 | pmc=4434237}}</ref> |
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==Production, structure, and basic reactions== |
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Chromium trioxide is generated by treating ] with ]:<ref name = chemicalland21 /> |
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:{{chem2|H2SO4 + Na2Cr2O7 → 2 CrO3 + Na2SO4 + H2O}} |
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Approximately 100,000 tonnes are produced annually by this or similar routes.<ref name=ullmanns/> |
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The solid consists of chains of tetrahedrally coordinated chromium atoms that share vertices. Each ] center therefore shares two oxygen centers with neighbors. Two oxygen atoms are not shared, giving an overall stoichiometry of 1:3.<ref name = cotton>{{Cotton&Wilkinson6th}}</ref><ref name=adb>{{Cite journal | doi = 10.1107/S0567740870002182| title = The crystal structure of (CrO<sub>3</sub>)<sub>∞</sub>| journal = Acta Crystallographica Section B| volume = 26| issue = 3| pages = 222| year = 1970| last1 = Stephens | first1 = J. S.| last2 = Cruickshank | first2 = D. W. J.}}</ref> ], Cr}}{{legend|red|], O}}]] |
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The structure of monomeric {{chem2|CrO3}} has been calculated using ], and is predicted to be ] (] C<sub>3v</sub>) rather than ] (point group D<sub>3h</sub>).<ref name=cdoi>{{Cite journal | doi = 10.1021/ja077984d| title = Probing the Electronic and Structural Properties of Chromium Oxide Clusters {{chem|(CrO|3|)|''n''|-}} and (CrO<sub>3</sub>)<sub>''n''</sub> (''n'' = 1–5): Photoelectron Spectroscopy and Density Functional Calculations| journal = Journal of the American Chemical Society| volume = 130| issue = 15| pages = 5167–77| year = 2008| last1 = Zhai | first1 = H. J. | last2 = Li | first2 = S. | last3 = Dixon | first3 = D. A. | last4 = Wang | first4 = L. S. |pmid = 18327905}}</ref> |
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:] |
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Chromium trioxide decomposes above 197 °C, liberating oxygen and eventually giving ]: |
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:{{chem2|4 CrO3 → 2 Cr2O3 + 3 O2}} |
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It is used in ] as an oxidant, often as a solution in ],<ref name = cotton /> or ] in the case of the ]. In these oxidations, the Cr(VI) converts ]s to the corresponding ]s and ]s to ]s. The reactions are shown below: |
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* Primary alcohols to carboxylic acids |
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*:{{chem2|4 CrO3 + 3 RCH2OH + 12 H+ → 3 RCOOH + 4 Cr(3+) + 9 H2O}} |
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* Secondary alcohols to ketones |
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*:{{chem2|2 CrO3 + 3 R2CHOH + 6 H+ → 3 R2C\dO + 2 Cr(3+) + 6 H2O}} |
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==Applications== |
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Chromium trioxide is mainly used in ]. It is typically employed with additives that affect the plating process but do not react with the trioxide. The trioxide reacts with ], ], and other metals to generate passivating chromate films that resist ]. It is also used in the production of ]. Chromic acid solution is also used in applying types of ] to ], which are primarily used in aerospace applications. On the International Space Station, it is used to control bacteria growth in the wastewater storage tank. A chromic acid/] solution is also the preferred ] of anodic coatings of all types. |
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==Safety== |
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Chromium trioxide is highly toxic, corrosive, and carcinogenic.<ref>{{cite web|url = http://hazard.com/msds/mf/baker/baker/files/c4400.htm|publisher = J. T. Baker|title = Chromium Trioxide (MSDS)|access-date = 2007-09-13|archive-url = https://web.archive.org/web/20150112092613/http://hazard.com/msds/mf/baker/baker/files/c4400.htm|archive-date = 2015-01-12|url-status = dead}}</ref> It is the main example of ], an ].<ref>The environmental impact of hexavalent chromium inspired the 2000 biographical Hollywood movie '']''.</ref> The related chromium(III) derivatives are not particularly dangerous; thus, ]s are used to destroy chromium(VI) samples. |
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Chromium trioxide, being a powerful oxidizer, will ignite organic materials such as ] ]. |
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== Images == |
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<gallery> |
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Reaction between potassium dichromate and sulfuric acid (1).jpg|A concentrated solution of potassium dichromate in water. |
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Reaction between potassium dichromate and sulfuric acid (2).jpg|Addition of sulfuric acid to the solution. |
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Reaction between potassium dichromate and sulfuric acid (3).jpg|Crystallization of chromium trioxide from the reaction. |
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</gallery> |
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<gallery> |
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Reaction between chromium(VI) oxide and ethanol (1).JPG|Reaction between chromium trioxide and ethanol |
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Reaction between chromium(VI) oxide and ethanol (2).JPG |
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Reaction between chromium(VI) oxide and ethanol (3).JPG |
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</gallery> |
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==References== |
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{{reflist}} |
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==External links== |
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{{Commons category|Chromium trioxide}} |
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* U.S. ] |
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* at '']'' (University of Nottingham) |
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* |
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{{Chromium compounds}} |
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{{Oxides}} |
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{{oxygen compounds}} |
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] |
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] |