| Revision as of 12:30, 15 February 2012 editBeetstra (talk | contribs)Edit filter managers, Administrators172,031 edits Saving copy of the {{chembox}} taken from revid 473820325 of page Barium_hydroxide for the Chem/Drugbox validation project (updated: ''). |
Latest revision as of 01:27, 6 October 2024 edit 2603:9001:4f00:1edb:457a:a0b6:618:773f (talk) →Laboratory uses: grammar |
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{{Chembox |
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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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| verifiedrevid = 464184740 |
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| verifiedrevid = 476994496 |
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| Name = Barium hydroxide |
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| Name = Barium hydroxide |
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| ImageFile1 = Ba(OH)2monohydrate.tif |
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| Section1 = {{Chembox Identifiers |
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| ImageFile2 = Ba(OH)2 octahydrate.JPG |
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| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}} |
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| ImageName = Barium hydroxide octahydrate |
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|Section1={{Chembox Identifiers |
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| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}} |
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| ChemSpiderID = 26408 |
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| ChemSpiderID = 26408 |
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| InChI = 1/Ba.2H2O/h;2*1H2/q+2;;/p-2 |
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| InChI = 1/Ba.2H2O/h;2*1H2/q+2;;/p-2 |
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| StdInChIKey = RQPZNWPYLFFXCP-UHFFFAOYSA-L |
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| StdInChIKey = RQPZNWPYLFFXCP-UHFFFAOYSA-L |
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| CASNo = 17194-00-2 |
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| CASNo = 17194-00-2 |
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| CASNo_Ref = {{cascite|correct|CAS}} |
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| CASNo_Ref = {{cascite|correct|CAS}} |
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| CASNo2_Ref = {{cascite|correct|CAS}} |
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| CASOther = <br> 22326-55-2 (monohydrate) <br> 12230-71-6 (octahydrate) |
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| CASNo2 = 22326-55-2 |
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| CASNo2_Comment = (monohydrate) |
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| CASNo3_Ref = {{cascite|correct|CAS}} |
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| CASNo3 = 12230-71-6 |
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| CASNo3_Comment = (octahydrate) |
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| UNII_Ref = {{fdacite|correct|FDA}} |
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| UNII = 1OHB71MYBK |
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| UNII2_Ref = {{fdacite|correct|FDA}} |
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| UNII2 = P27GID97XM |
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| UNII2_Comment = (monohydrate) |
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| UNII3_Ref = {{fdacite|correct|FDA}} |
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| UNII3 = L5Q5V03TBN |
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| UNII3_Comment = (octahydrate) |
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| RTECS = CQ9200000 |
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| RTECS = CQ9200000 |
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| PubChem = 28387 |
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| PubChem = 28387 |
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| Gmelin = 846955 |
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| EINECS = 241-234-5 |
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}} |
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| Section2 = {{Chembox Properties |
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|Section2={{Chembox Properties |
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| Formula = Ba(OH)<sub>2</sub> |
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| Formula = Ba(OH)<sub>2</sub> |
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| MolarMass = 171.34 g/mol (anhydrous) <br> 189.39 g/mol (monohydrate) <br> 315.46 g/mol (octahydrate) |
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| MolarMass = 171.34 g/mol (anhydrous) <br> 189.355 g/mol (monohydrate) <br> 315.46 g/mol (octahydrate) |
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| Appearance = white solid |
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| Appearance = white solid |
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| Solubility = ''octahydrate:'' <br> 1.67 g/100 mL (0 °C) <br> 3.89 g/100 mL (20 °C) <br> 11.7 g/100 mL (50 °C) <br> 20.94 g/100 mL (60 °C) <br> 101.4 g/100 mL (100 °C) |
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| Solubility = ''mass of BaO (not Ba(OH)<sub>2</sub>):'' <br> 1.67 g/100 mL (0 °C) <br> 3.89 g/100 mL (20 °C) <br> 4.68 g/100 mL (25 °C) <br> 5.59 g/100 mL (30 °C) <br> 8.22 g/100 mL (40 °C) <br> 11.7 g/100 mL (50 °C) <br> 20.94 g/100 mL (60 °C) <br> 101.4 g/100 mL (100 °C){{Citation needed|date=May 2020}} |
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| Solvent = other solvents |
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| Solvent = other solvents |
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| SolubleOther = low |
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| SolubleOther = low |
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| MeltingPtC = 78 |
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| MeltingPt = 78 °C (octahydrate)<br /> 300°C (monohydrate) <br> 407 °C (anhydrous) |
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| MeltingPt_notes = (octahydrate)<br/>300 °C (monohydrate) <br> 407 °C (anhydrous) |
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| BoilingPt = 780 °C |
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| BoilingPtC = 780 |
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| Density = 3.743 g/cm<sup>3</sup> (monohydrate) <br> 2.18 g/cm<sup>3</sup> (octahydrate, 16 °C) |
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| BoilingPt_notes = |
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| RefractIndex = 1.50 (octahydrate) |
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| Density = 3.743 g/cm<sup>3</sup> (monohydrate) <br> 2.18 g/cm<sup>3</sup> (octahydrate, 16 °C) |
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| pKb = -2.02 |
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| RefractIndex = 1.50 (octahydrate) |
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| pKb = 0.15 (first OH<sup>–</sup>), 0.64 (second OH<sup>–</sup>)<ref>{{cite web|language=de|url=http://www.periodensystem-online.de/index.php?show=list&id=acid&prop=pKb-Werte&sel=oz&el=92|title=Sortierte Liste: pKb-Werte, nach Ordnungszahl sortiert. - Das Periodensystem online}}</ref> |
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| MagSus = −53.2·10<sup>−6</sup> cm<sup>3</sup>/mol }} |
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|Section3={{Chembox Structure |
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| Coordination = |
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| CrystalStruct = octahedral |
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| Section3 = {{Chembox Structure |
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|Section4={{Chembox Thermochemistry |
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| Thermochemistry_ref = <ref>{{CRC90}}</ref> |
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| Coordination = |
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| DeltaHf = −944.7 kJ·mol<sup>−1</sup> |
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| CrystalStruct = octahedral |
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| DeltaHfus = 16 kJ·mol<sup>−1</sup> |
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| Section4 = {{Chembox Thermochemistry |
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|Section7={{Chembox Hazards |
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| NFPA-H = 3 |
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| DeltaHf = −944.7 kJ/mol |
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| NFPA-F = 1 |
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| NFPA-R = 1 |
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| GHSPictograms = {{GHS05}}{{GHS07}} |
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| GHSSignalWord = Danger |
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| HPhrases = {{H-phrases|302|314|332|412}} |
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| PPhrases = {{P-phrases|}} |
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| FlashPt = Non-flammable |
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| LD50 = 308 mg/kg (rat, oral) |
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| ExternalSDS = |
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| Section7 = {{Chembox Hazards |
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|Section8={{Chembox Related |
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| OtherAnions = ]<br />] |
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| EUClass = Harmful ('''Xn''') |
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| OtherCations = ]<br />] |
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| EUIndex = 056-002-00-7 |
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| NFPA-H = 3 |
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| NFPA-F = 0 |
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| NFPA-R = 0 |
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| RPhrases = {{R20/22}} |
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| SPhrases = {{S2}}, {{S28}} |
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| FlashPt = non-flammable |
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}} |
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| Section8 = {{Chembox Related |
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| OtherAnions = ]<br />] |
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| OtherCations = ]<br />] |
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'''Barium hydroxide''' is a ] with the ] Ba(OH)<sub>2</sub>. The monohydrate (''x'' = 1), known as baryta or baryta-water, is one of the principal compounds of ]. This white granular ] is the usual commercial form. |
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==Preparation and structure== |
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Barium hydroxide can be prepared by dissolving ] (BaO) in ]: |
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:BaO + H<sub>2</sub>O → Ba(OH)<sub>2</sub> |
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It crystallises as the octahydrate, which converts to the monohydrate upon heating in air. At 100 °C in a vacuum, the monohydrate will yield BaO and water.<ref>(1960). ''Gmelins Handbuch der anorganischen Chemie (8. Aufl.)'', Weinheim: Verlag Chemie, p. 289.</ref> The monohydrate adopts a layered structure (see picture above). The Ba<sup>2+</sup> centers adopt a ]. Each Ba<sup>2+</sup> center is bound by two water ]s and six hydroxide ligands, which are respectively doubly and triply bridging to neighboring Ba<sup>2+</sup> centre sites.<ref>Kuske, P.; Engelen, B.; Henning, J.; Lutz, H.D.; Fuess, H.; Gregson, D. "Neutron diffraction study of Sr(OH)<sub>2</sub>(H<sub>2</sub>O) and beta-Ba(OH)<sub>2</sub>*(H<sub>2</sub>O)" Zeitschrift für Kristallographie (1979-2010) 1988, vol. 183, p319-p325.</ref> In the octahydrate, the individual Ba<sup>2+</sup> centers are again eight coordinate but do not share ligands.<ref>Manohar, H.; Ramaseshan, S. "The crystal structure of barium hydroxide octahydrate Ba (OH)<sub>2</sub>(H<sub>2</sub>O)<sub>8</sub>" Zeitschrift für Kristallographie, Kristallgeometrie, Kristallphysik, Kristallchemie 1964. vol. 119, p357-p374</ref> |
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] |
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==Uses== |
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Industrially, barium hydroxide is used as the precursor to other barium compounds. The monohydrate is used to dehydrate and remove sulfate from various products.<ref name=Ullmann>Robert Kresse, Ulrich Baudis, Paul Jäger, H. Hermann Riechers, Heinz Wagner, Jochen Winkler, Hans Uwe Wolf, "Barium and Barium Compounds" in Ullmann's Encyclopedia of Industrial Chemistry, 2007 Wiley-VCH, Weinheim. {{doi|10.1002/14356007.a03_325.pub2}}</ref> This application exploits the very low solubility of ]. This industrial application is also applied to laboratory uses. |
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===Laboratory uses=== |
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Barium hydroxide is used in ] for the ] of ]s, particularly ]s. Its aqueous solution, if clear, is guaranteed to be free of carbonate, unlike those of ] and ], as ] is insoluble in water. This allows the use of indicators such as ] or ] (with alkaline colour changes) without the risk of titration errors due to the presence of ] ions, which are much less basic.<ref>{{VogelQuantitative}}</ref> |
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Barium hydroxide is occasionally used in ] as a strong base, for example for the hydrolysis of esters<ref>Meyer, K.; Bloch, H. S. (1945). "". '']'' '''25''': 73; ''Coll. Vol.'' '''3''': 637.</ref> and nitriles,<ref>Brown, G. B. (1946). "". '']'' '''26''': 54; ''Coll. Vol.'' '''3''': 615.</ref><ref>Ford, Jared H. (1947). "". '']'' '''27''': 1; ''Coll. Vol.'' '''3''': 34.</ref><ref>Anslow, W. K.; King, H.; Orten, J. M.; Hill, R. M. (1925). "". '']'' '''4''': 31; ''Coll. Vol.'' '''1''': 298.</ref> and as a base in ]s. |
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There are several uses for barium hydroxide such as to hydrolyse one of the two equivalent ester groups in dimethyl hendecanedioate.<ref>Durham, L. J.; McLeod, D. J.; Cason, J. (1958). "". '']'' '''38''':55; ''Coll. Vol.'' '''4''':635.</ref> |
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Barium hydroxide has also been used in the decarboxylation of amino acids liberating barium carbonate in the process.<ref>{{Cite book|url=https://books.google.com/books?id=S4nrnTkBph0C|title = Biochemistry and Clinical Pathology|isbn = 9788185790169|last1 = Chaudhari|first1 = M. R.|last2 = Kulkarni|first2 = Y. A.|last3 = Gokhale|first3 = S. B.|date = 6 October 2008| publisher=Pragati Books Pvt. }}</ref> |
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It is also used in the preparation of ],<ref>Thorpe, J. F.; Kon, G. A. R. (1925). "". '']'' '''5''': 37; ''Coll. Vol.'' '''1''': 192.</ref> ]<ref>Conant, J. B.; Tuttle, Niel. (1921). "". '']'' '''1''': 45; ''Coll. Vol.'' '''1''': 199.</ref> and ].<ref>Karabinos, J. V. (1956). "". '']'' '''36''': 38; ''Coll. Vol.'' '''4''': 506.</ref> |
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==Reactions== |
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Barium hydroxide decomposes to ] when heated to 800 °C. Reaction with ] gives ]. Its aqueous solution, being highly alkaline, undergoes neutralization reactions with acids. It is especially useful on reactions that require the titrations of weak organic acids. Thus, it forms ] and ] with sulfuric and phosphoric acids, respectively. Reaction with ] produces ]. Precipitation of many insoluble, or less soluble barium salts, may result from double replacement reaction when a barium hydroxide aqueous solution is mixed with many solutions of other metal salts.<ref>Pradyot Patnaik. ''Handbook of Inorganic Chemicals''. McGraw-Hill, 2002, {{ISBN|0-07-049439-8}}</ref> |
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Reactions of barium hydroxide with ] salts are strongly ]. The reaction of barium hydroxide octahydrate with ]<ref name=UCSD>{{cite web|title=Endothermic Reactions of Hydrated Barium Hydroxide and Ammonium Chloride|url=http://www-chem.ucsd.edu/undergraduate/teaching-labs/demos/demo45.html|publisher=UC San Diego|access-date=2 April 2014}}</ref><ref></ref> or<ref name=UW /> ]<ref name=UW>{{cite web|last=Camp|first=Eric|title=Endothermic Reaction|url=http://depts.washington.edu/chem/facilserv/lecturedemo/EndothermicReaction-UWDept.ofChemistry.html|publisher=Univertist of Washington|access-date=2 April 2014}}</ref><ref name=RSC>{{cite web|title=Endothermic solid-solid reactions |url=http://media.rsc.org/Classic%20Chem%20Demos/CCD-44.pdf |work=Classic Chemistry Demonstrations |publisher=The Royal Society of Chemistry |access-date=2 April 2014 |url-status=dead |archive-url=https://web.archive.org/web/20140407092124/http://media.rsc.org/Classic%20Chem%20Demos/CCD-44.pdf |archive-date=7 April 2014 }}</ref> is often used as a classroom chemistry demonstration, producing temperatures cold enough to freeze water and enough water to dissolve the resulting mixture. |
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==Safety== |
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Barium hydroxide presents the same hazards such as skin irritation and burns as well as eye damage, just as the other ]s and as other water-soluble barium compounds: it is corrosive and toxic. {{Citation needed|date=November 2016}} |
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==See also== |
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* ] |
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==References== |
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{{reflist}} |
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==External links== |
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* |
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{{Barium compounds}} |
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{{Hydroxides}} |
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] |
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] |