查看“︁氢氧化钡”︁的源代码

{{Chembox
| Name = 氢氧化钡
| ImageFile = Ba(OH)2 octahydrate.JPG
|ImageFile1= Ba(OH)2monohydrate.tif
| ImageName = 八水合氢氧化钡
| Section1 = {{Chembox Identifiers
| CASNo = 17194-00-2
| CASNo_Ref = {{cascite|correct|CAS}}
| CASNo1 = 22326-55-2
| CASNo1_Comment =  一水合物
| CASNo1_Ref = {{cascite|changed|??}}
| CASNo2 = 12230-71-6
| CASNo2_Comment =  八水合物
| CASNo2_Ref = {{cascite|changed|??}}
|  RTECS  =  CQ9200000 
|  ChemSpiderID_Ref  = {{chemspidercite|correct|chemspider}}|  ChemSpiderID  =  26408
|  InChI  =  1/Ba.2H2O/h;2*1H2/q+2;;/p-2
|  ChEBI_Ref  = {{ebicite|correct|EBI}}|  ChEBI  =  32592
|  SMILES  =  [Ba+2].[OH-].[OH-]
|  InChIKey  =  RQPZNWPYLFFXCP-NUQVWONBAR
|  StdInChI_Ref  = {{stdinchicite|correct|chemspider}}|  StdInChI  =  1S/Ba.2H2O/h;2*1H2/q+2;;/p-2
|  StdInChIKey_Ref  = {{stdinchicite|correct|chemspider}}|  StdInChIKey  =  RQPZNWPYLFFXCP-UHFFFAOYSA-L
|  PubChem  =  28387
|  Gmelin  =  846955
}}
| Section2 = {{Chembox Properties
| Formula = Ba(OH)<sub>2</sub>
| MolarMass = 171.342 g/mol（无水）<br />189.36 g/mol（一水合物）<br />315.46 g/mol（八水合物）
| Appearance = 白色固体
| Solubility = 5.6 g/100 g（八水合物）
| Solvent = 其它溶剂
| SolubleOther = 微溶
| MeltingPt = 78 °C（八水合物）<br />&gt;408 °C（无水）
| BoilingPt = 780 °C
| pKb=0.15 (第一个 OH<sup>−</sup>), 0.64 (第二个 OH<sup>−</sup>) <ref>{{cite web|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|publisher=|accessdate=2019-01-15|archive-date=2018-11-16|archive-url=https://web.archive.org/web/20181116050427/http://www.periodensystem-online.de/index.php?show=list&id=acid&prop=pKb-Werte&sel=oz&el=92|dead-url=yes}}</ref> }}
| Section3 = {{Chembox Structure
| Coordination =
| CrystalStruct = 八面体
  }}
| Section4 = {{Chembox Thermochemistry
| DeltaHf = &minus;944.7 kJ/mol
  }}
| Section7 = {{Chembox Hazards
| wxxfh={{wxxfh|Xn}}
| NFPA-H = 3
| NFPA-F =0
| NFPA-R =0
  NFPA-O =ALK
| RPhrases = {{R35}}-{{R37/38}}
| SPhrases = {{S2}}-{{S28}}
| FlashPt = 不可燃
  }}
| Section8 = {{Chembox Related
| OtherAnions = [[氧化钡]]、[[过氧化钡]]
| OtherCations = [[氢氧化钙]]、[[氢氧化锶]]
  }}
}}
'''氫氧化鋇'''是[[鋇]]的[[氢氧化物]]，[[分子式]]為Ba(OH)<sub>2</sub>，為白色顆粒狀固体。

== 用途 ==
工业上，氢氧化钡是其它钡化合物的前体。它的一水合物可用来脱水和在产品中移除硫酸盐。<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>该应用利用了硫酸钡极低的溶解度。这种工业应用也适用于实验室用途。

===实验室用处===
氢氧化钡在[[分析化学]]中用于[[滴定]][[弱酸]]，特别是[[有机酸]]。它与[[氢氧化钠]]和[[氢氧化钾]]不同，其水溶液不含碳酸盐，因为[[碳酸钡]]不溶于水。这使得例如[[酚酞]]或[[百里酚酞]]（具有碱性颜色变化）的指示剂不会因[[碳酸根]]离子的存在而导致滴定错误。<ref>{{VogelQuantitative}}</ref>

氢氧化钡偶尔在[[有机合成]]中用作强碱，例如水解酯<ref>Meyer, K.; Bloch, H. S. (1945). "[http://www.orgsyn.org/orgsyn/prep.asp?prep=cv3p0637 Naphthoresorcinol] {{Wayback|url=http://www.orgsyn.org/orgsyn/prep.asp?prep=cv3p0637 |date=20120607005319 }}". ''[[Org. Synth.]]'' '''25''': 73; ''Coll. Vol.'' '''3''': 637.</ref>和腈<ref>Brown, G. B. (1946). "[http://www.orgsyn.org/orgsyn/prep.asp?prep=cv3p0615 Methylsuccinic acid] {{Wayback|url=http://www.orgsyn.org/orgsyn/prep.asp?prep=cv3p0615 |date=20120609211222 }}". ''[[Org. Synth.]]'' '''26''': 54; ''Coll. Vol.'' '''3''': 615.</ref><ref>Ford, Jared H. (1947). "[http://www.orgsyn.org/orgsyn/prep.asp?prep=cv3p0034 β-Alanine] {{Wayback|url=http://www.orgsyn.org/orgsyn/prep.asp?prep=cv3p0034 |date=20120609211310 }}". ''[[Org. Synth.]]'' '''27''': 1; ''Coll. Vol.'' '''3''': 34.</ref><ref>Anslow, W. K.; King, H.; Orten, J. M.; Hill, R. M. (1925). "[http://www.orgsyn.org/orgsyn/prep.asp?prep=cv1p0298 Glycine] {{Wayback|url=http://www.orgsyn.org/orgsyn/prep.asp?prep=cv1p0298 |date=20120609211324 }}". ''[[Org. Synth.]]'' '''4''': 31; ''Coll. Vol.'' '''1''': 298.</ref>，也在[[羟醛缩合]]中作为碱。

:[[File:Barium hydroxide-catalyzed 2-carboxy-1,3-dihydroxynaphthalene preparation.svg|418px]]
:[[File:Barium hydroxide-catalyzed methylsuccinic acid preparation.svg|346px]]

它可用于水解十一烷二酸二甲酯中，两个等价的甲酯基团之一。<ref>Durham, L. J.; McLeod, D. J.; Cason, J. (1958). "[http://www.orgsyn.org/orgsyn/prep.asp?prep=cv4p0635 Methyl hydrogen hendecanedioate] {{Wayback|url=http://www.orgsyn.org/orgsyn/prep.asp?prep=cv4p0635 |date=20201203221850 }}". ''[[Org. Synth.]]'' '''38''':55; ''Coll. Vol.'' '''4''':635.</ref>

氢氧化钡也用于氨基酸的脱羧，并释放碳酸钡。<ref>{{Cite web |url=https://books.google.com/books?id=S4nrnTkBph0C&printsec=frontcover&hl=es#v=onepage&q&f=false |title=存档副本 |access-date=2021-07-14 |archive-date=2021-07-14 |archive-url=https://web.archive.org/web/20210714141009/https://books.google.com/books?id=S4nrnTkBph0C&printsec=frontcover&hl=es#v=onepage&q&f=false |dead-url=no }}</ref>

氢氧化钡也用于制备[[环戊酮]]<ref>Thorpe, J. F.; Kon, G. A. R. (1925). "[http://www.orgsyn.org/orgsyn/prep.asp?prep=cv1p0192 Cyclopentanone] {{Wayback|url=http://www.orgsyn.org/orgsyn/prep.asp?prep=cv1p0192 |date=20120609211402 }}". ''[[Org. Synth.]]'' '''5''': 37; ''Coll. Vol.'' '''1''': 192.</ref>和[[二丙酮醇]]<ref>Conant, J. B.; Tuttle, Niel. (1921). "[http://www.orgsyn.org/orgsyn/prep.asp?prep=cv1p0199 Diacetone alcohol] {{Wayback|url=http://www.orgsyn.org/orgsyn/prep.asp?prep=cv1p0199 |date=20120609211442 }}". ''[[Org. Synth.]]'' '''1''': 45; ''Coll. Vol.'' '''1''': 199.</ref>

:[[File:Cyclopentanone prepn.png|275px]]
:[[File:Barium hydroxide-catalyzed diacetone alcohol preparation.svg|275px]]

== 製备和结构 ==
直接把[[氧化鋇]]（BaO）和[[水]]混合來製备氫氧化鋇：

:<chem>BaO + 9H2O -> Ba(OH)2* 8H2O</chem>

反应产生的是八水合物，它在空气中加热时失水成一水合物。在 100&nbsp;°C 的真空下，一水合物直接分解成 BaO 和水。<ref>(1960). ''Gmelins Handbuch der anorganischen Chemie (8. Aufl.)'', Weinheim: Verlag Chemie, p. 289.</ref>一水合物是层状结构的（见上图）。Ba<sup>2+</sup> 中心为[[四方反棱柱]]结构，每个Ba<sup>2+</sup> 中心都被两个水[[配體]]和六个氢氧根配体包围，而它们分别被两个和三个 Ba<sup>2+</sup>包围。<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>在八水合物中， Ba<sup>2+</sup>中心是八配位的，不共享配体。<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>
[[File:Ba(OH)2O2HCoordSph.tif|thumb|left|钡离子在 Ba(OH)<sub>2</sub>·H<sub>2</sub>O中的配位圈]]

== 反應 ==
氢氧化钡在 800&nbsp;°C以上分解成[[氧化钡]]。它和[[二氧化碳]]反应，形成[[碳酸钡]]。氢氧化钡水溶液是强碱性的，会和酸中和。因此，它分别和硫酸和磷酸反应，形成[[硫酸钡]]和[[磷酸钡]]。氢氧化钡和[[硫化氢]]反应，形成[[硫化钡]]。当氢氧化钡水溶液与其它金属盐溶液混合时，会产生不溶性或难溶性钡盐的沉淀，可能是由置换反应引起的。<ref>Pradyot Patnaik. ''Handbook of Inorganic Chemicals''. McGraw-Hill, 2002, {{ISBN|0-07-049439-8}}</ref>

氢氧化钡和[[铵盐]]的反应是强[[吸热过程]]。八水合氢氧化钡和[[氯化铵]]<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|archive-date=2021-01-15|archive-url=https://web.archive.org/web/20210115210341/https://www-chem.ucsd.edu/undergraduate/teaching-labs/demos/demo45.html|dead-url=no}}</ref><ref>{{Cite web |url=http://www.nuffieldfoundation.org/practical-chemistry/endothermic-solid-solid-reactions |title=Endothermic Solid-Solid Reactions |access-date=2021-07-14 |archive-date=2016-07-14 |archive-url=https://web.archive.org/web/20160714025734/http://www.nuffieldfoundation.org/practical-chemistry/endothermic-solid-solid-reactions |dead-url=no }}</ref> 或[[硫氰酸铵]]<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|archive-date=2020-01-10|archive-url=https://web.archive.org/web/20200110205514/http://depts.washington.edu/chem/facilserv/lecturedemo/EndothermicReaction-UWDept.ofChemistry.html|dead-url=no}}</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> 的反应通常用作课堂化学演示，会产生足够冷的温度以冻结水。

== 危险性 ==
类似于其他的[[强碱]]，氢氧化钡具有[[腐蚀性]]。

==参考资料==
{{reflist}}
{{氢氧化物}}
{{鋇化合物}}

[[Category:氢氧化物]]
[[Category:钡化合物]]