查看“︁钨酸”︁的源代码

{{chemref|time=2013-02-01T06:40:20+00:00 }}
{{chembox
| Name = 钨酸（一水）
| ImageFile = H2WO4.png
| ImageName = 正钨酸（一水）
| ImageFile2 = Tungstic acid.jpg
| OtherNames = 钨酸<br />正钨酸<br />一水合氧化钨
| Section1 = {{Chembox Identifiers
|   CASNo = 7783-03-1
|   CASNo_Ref = {{cascite}}
|   RTECS = 
  }}
| Section2 = {{Chembox Properties
|   Formula = H<sub>2</sub>WO<sub>4</sub>
|   MolarMass = 249.85
|   Appearance = 黄色粉末<ref name=roempp>{{RömppOnline|Name=Wolframsäure |Datum=7. Januar 2018 |ID=RD-23-01044 }}</ref><ref name="GESTIS" />
|   Density = 5.5 g/cm<sup>3</sup><ref name="GESTIS">{{GESTIS|Name=Wolframsäure|ZVG=122698|CAS=7783-03-1|Datum=19. Dezember 2019}}</ref>
|   Solubility = 不溶
|   SolOther = 不溶于酸<ref name=roempp/>，溶于碱液<ref name=roempp/>、[[氢氟酸]]及[[氨水]]
|   MeltingPt = 100 °C
|   Melting_notes = 分解<ref name="GESTIS" />
|   BoilingPt = 
|   pKa1 = 3.5<ref name="Holleman-Wiberg">{{Holleman-Wiberg|Auflage=101.|Startseite=?}}</ref>
|   pKa2 = 4.6<ref name="Holleman-Wiberg" />
  }}
| Section3 = {{Chembox Structure
|   Coordination =
|   CrystalStruct = 
  }}
| Section7 = {{Chembox Hazards
|   ExternalMSDS = 
|   EUIndex =
|   EUClass = 
|   RPhrases = 
|   SPhrases = 
|   MainHazards = 
|   NFPA-H = 2
|   NFPA-F = 0
|   NFPA-R = 0
|   NFPA-O = 
|   FlashPt =
  }}
| Section8 = {{Chembox Related
|   OtherAnions = 
|   OtherCations = [[铬酸]]<br />[[钼酸]]
|   OtherFunctn = 
|    Function = 
|   OtherCpds = 
  }}
}}

'''钨酸'''是[[三氧化钨]]（WO<sub>3</sub>）各種[[水合物]]形態的總稱。三氧化钨一水合物（WO<sub>3</sub>·H<sub>2</sub>O）和半水合物（WO<sub>3</sub>·0.5H<sub>2</sub>O）<ref>{{cite journal|doi=10.1016/0025-5408(89)90214-6|title=Direct synthesis and single crystal structure determination of cubic pyrochlore-type tungsten trioxide hemihydrate, WO3 · 0.5H2O|url=https://archive.org/details/sim_materials-research-bulletin_1989-03_24_3/page/289|journal=Materials Research Bulletin|volume=24|issue=3|pages=289–292|year=1989|last1=Günter|first1=John R.|last2=Amberg|first2=Marcel|last3=Schmalle|first3=Helmut}}</ref>都是已知的。而类似硫酸结构的(HO)<sub>2</sub>WO<sub>2</sub>的钨酸分子未被发现。

==性质==
黄色粉末。加热至100°C时失去一分子水而转变为[[三氧化钨]]。几乎不溶于酸，微溶于热水，溶于碱、[[氢氟酸]]和[[氨水]]。钨酸比[[三氧化钨]]更容易溶于碱。<ref name=roempp/>

==历史==
最早由[[卡尔·威廉·舍勒]]于1781年分离出来。<ref>Scheele, Carl Wilhelm (1781) [https://babel.hathitrust.org/cgi/pt?id=nyp.33433012786798;view=1up;seq=99 "Tungstens bestånds-delar"] {{Wayback|url=https://babel.hathitrust.org/cgi/pt?id=nyp.33433012786798;view=1up;seq=99 |date=20210427232327 }} (Tungsten's [i.e., [[Scheelite]]'s] constituents), ''Kungliga Vetenskaps Academiens Nya Handlingar'' (Royal Scientific Academy's New Proceedings), '''2''': 89–95. (in Swedish)</ref>

==制备==
钨酸可由[[钨酸钙]]与[[盐酸]]作用产生。<ref name="brauer">[[Georg Brauer]] (Hrsg.) u.&nbsp;a.: ''Handbuch der Präparativen Anorganischen Chemie.'' 3., umgearbeitete Auflage. Band III, Ferdinand Enke, Stuttgart 1981, ISBN 3-432-87823-0, S. 1566.</ref>
:<math>\rm \ CaWO_4+2HCl\rightarrow H_2WO_4+CaCl_2</math>

它也可通过精[[钨酸铵]]溶液用[[盐酸]]酸解得到。{{cn}}
:<math>\rm \ 5 (NH_4)_2O\cdot 12WO_3+10HCl+7H_2O\rightarrow 12H_2WO_4+10NH_4Cl</math>

纯钨和[[过氧化氢]]反应，也可以得到钨酸。<ref name="Murau">{{cite news|last=Murau|first=P. C.|title=Dissolution of Tungsten by Hydrogen Peroxide|year=1961|publisher=Analytical Chemistry|doi=10.1021/ac60176a021|pages=1125–1126}}</ref>

==用途==
用作制取金属[[钨]]、[[钨合金]]、[[钨酸盐]]类和硬质合金的原料。也用作石油催化剂、印染助剂和润滑剂。

== 参考资料 ==
{{reflist}}

{{无机酸}}
{{钨化合物}}
{{Authority control}}

[[Category:钨化合物]]
[[Category:无机酸]]
[[Category:钨酸盐|*]]
[[Category:1780年代发现的物质]]