查看“︁亚硫酸钙”︁的源代码

{{NoteTA|G1=Chemistry}}
{{chembox
| Verifiedfields = changed
| verifiedrevid = 433612289
| ImageFile=CaSO30.5aq.png
| ImageSize=240px
| ImageFile1=Calcium sulfite.png
| IUPACName=Calcium sulfite
| OtherNames=E226
|Section1={{Chembox Identifiers
| CASNo = 10257-55-3
| CASNo_Comment = 无水
| CASNo_Ref = {{cascite|correct|CAS}}
| CASNo1 = 72878-03-6
| CASNo1_Comment = 四水
| CASNo1_Ref = {{cascite|correct|NIST}}
| CASNo2 = 29501-28-8
| CASNo2_Comment = 半水
| CASNo2_Ref = {{cascite|correct|NIST}}
| PubChem = 159274
| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}
| ChemSpiderID = 8329549
| InChI = 1/Ca.H2O3S/c;1-4(2)3/h;(H2,1,2,3)/q+2;/p-2
| SMILES = [Ca+2].[O-]S([O-])=O
| InChIKey = GBAOBIBJACZTNA-NUQVWONBAU
| StdInChI_Ref = {{stdinchicite|correct|chemspider}}
| StdInChI = 1S/Ca.H2O3S/c;1-4(2)3/h;(H2,1,2,3)/q+2;/p-2
| StdInChIKey_Ref = {{stdinchicite|changed|chemspider}}
| UNII_Ref = {{fdacite|changed|FDA}}
| UNII = 7078964UQP
  }}
|Section2={{Chembox Properties
| Formula = CaSO<sub>3</sub>
| MolarMass = 120.17
| Appearance = 白色固体
| MeltingPtC = 600
| BoilingPt =
| Solubility = 0.0043 g/100 mL, 18℃
  }}
|Section3={{Chembox Hazards
| ExternalSDS = 
| FlashPt = 不可燃
  }}
|Section8={{Chembox Related
| OtherAnions = [[硫酸钙]]
| OtherCations = [[亚硫酸钠]]
  }}
}}

'''亚硫酸钙'''属于[[亚硫酸盐]]与钙盐，化学式<chem>CaSO3.xH2O</chem>。亚硫酸钙有两种已知结晶水合物：半水合亚硫酸钙<chem>CaSO3.1/2H2O</chem>与四水合亚硫酸钙<chem>CaSO3.4H2O</chem><ref name=Xray>{{cite journal|journal=Chemistry Letters|pages=1051–1054|year= 1984|doi=10.1246/cl.1984.1051|title=Studies On Alkaline Earth Sulfites. Structure and Stability of the New Compound Ca<sub>3</sub>(SO<sub>3</sub>)<sub>2</sub>SO<sub>4</sub><sup>.</sup>12H<sub>2</sub>O and Its Solid Solution In Calcium Sulfite Tetrahydrate|author1=Abraham Cohen|author2=Mendel Zangen}}</ref>，均为白色固体。亚硫酸钙是[[烟气脱硫]]的产物之一。

== 用途 ==
=== 乾壁 ===
在制备[[乾壁]]的主要成分[[石膏]]的过程中，亚硫酸钙是一种中间产物。一间典型的全新美国房屋含有7公吨石膏<ref>{{Cite web|url = http://minerals.usgs.gov/minerals/pubs/commodity/gypsum/|title = USGS Gypsum Statistics and Information|date = |accessdate = 2017-08-02|website = USGS|publisher = |last = |first = |archive-date = 2017-05-13|archive-url = https://web.archive.org/web/20170513061705/https://minerals.usgs.gov/minerals/pubs/commodity/gypsum/|dead-url = no}}</ref>。

=== 食品添加剂 ===
亚硫酸钙可用作防腐剂，[[E编码]]为E226<ref>{{cite web |title=Current EU approved additives and their E Numbers |publisher=Food Standards Agency |location=United Kingdom |year=2010 |url=http://www.food.gov.uk/safereating/chemsafe/additivesbranch/enumberlist |accessdate=2017-08-04 |archive-date=2012-02-07 |archive-url=https://web.archive.org/web/20120207124535/http://www.food.gov.uk/safereating/chemsafe/additivesbranch/enumberlist |dead-url=no }}</ref>。与其他[[亚硫酸盐]][[抗氧化剂]]类似，亚硫酸钙广泛用于保存葡萄酒、苹果酒、水果汁、罐头水果、蔬菜等<ref>{{cite web|author1=Sulfites.org|title=Sulfites in Foods|url=http://www.sulfites.org/sulfite-foods/|accessdate=2017-08-04|archive-date=2017-08-01|archive-url=https://web.archive.org/web/20170801142821/http://www.sulfites.org/sulfite-foods/|dead-url=no}}</ref>。在溶液中，亚硫酸盐是强还原剂，作为{{tsl|en|oxygen scavenger||除氧剂}}起到保存食品的作用。因为部分人群对亚硫酸盐[[过敏]]，所以有必要对其进行标注。<ref>{{cite journal|last1=García-Gavín|first1=Juan|last2=Parente|first2=Joana|last3=Goossens|first3=An|title=Allergic contact dermatitis caused by sodium metabisulfite: a challenging allergen. A case series and literature review|journal=Contact Dermatitis|date=2012-11|volume=67|issue=5|pages=260–269|doi=10.1111/j.1600-0536.2012.02135.x}}</ref><ref>{{cite journal|last1=Vally|first1=H.|last2=Misso|first2=N. L. A.|last3=Madan|first3=V.|title=Clinical effects of sulphite additives|url=https://archive.org/details/sim_clinical-and-experimental-allergy_2009-11_39_11/page/1643|journal=Clinical & Experimental Allergy|date=2009-11|volume=39|issue=11|pages=1643–1651|doi=10.1111/j.1365-2222.2009.03362.x}}</ref>

=== 木浆生产 ===
化学木浆的生产过程是溶解掉木片中的[[木质素]]，分离出原本与前者紧密结合的纤维素。在{{tsl|en|sulfite process||亚硫酸盐制浆法}}中，用来分离木质素的盐可以是亚硫酸钙。人们曾经用过亚硫酸钙，但如今镁和钠的亚硫酸盐与亚硫酸氢盐已广泛取代之。另一种制浆法是[[硫酸盐制浆法]]，使用的是氢氧化物与[[硫化物]]。{{cn}}

=== 酸抑制剂 ===
煤中的[[二硫化铁]]在空气中煅烧会生成酸性气体，溶于水形成酸，污染环境：
* <math>\rm FeS_2 + 3.5O_2 + H_2O \rightarrow Fe^{2+} + 2SO_4^{2-} + 2H^+</math>
* <math>\rm 2Fe^{2+} + 0.5O_2 + 2H^+ \rightarrow 2Fe^{3+} + H_2O</math>
* <math>\rm FeS_2 + 14Fe^{3+} + 8H_2O \rightarrow 15Fe^{2+} + 16H^+ + 2SO_4^{2-}</math>
亚硫酸盐具有还原性，可以除去氧气从而抑制酸的形成。亚硫酸的钠盐、钾盐和铵盐都相对较贵且生产规模较小，而已经大规模生产的亚硫酸钙是该过程中较理想的酸抑制剂。<ref>{{cite journal|last1=Hao|first1=Yueli|last2=Dick|first2=Warren A.|title=Potential Inhibition of Acid Formation in Pyritic Environments Using Calcium Sulfite Byproduct|journal=Environmental Science & Technology|date=2000-06|volume=34|issue=11|pages=2288–2292|doi=10.1021/es9904235}}</ref>

== 制备 ==
{{Main article|烟气脱硫}}
通过[[烟气脱硫]]（FGD）可大量制备亚硫酸钙。[[烟道气]]指的是煤等化石燃料燃烧后得到的一类副产物，通常包括SO<sub>2</sub>。人们为了防止[[酸雨]]而限制二氧化硫排放，在其他气体从[[烟囱]]排出之前，需要除去二氧化硫。比较经济的做法是用[[氢氧化钙|熟石灰]]（Ca(OH)<sub>2</sub>）或[[石灰岩|石灰石]]（CaCO<sub>3</sub>）处理。

理想状况下，用石灰石除去二氧化硫的反应如下：

: SO<sub>2</sub>  +  CaCO<sub>3</sub>   →  CaSO<sub>3</sub>  +  CO<sub>2</sub>

理想状况下，用熟石灰除去二氧化硫的反应如下：<ref>{{Cite book|title = Sulfur Oxidation in Scrubber Systems|last = Hudson|first = JL|publisher = University of Virginia|year = 1980|isbn = |location = |pages = }}</ref><ref>{{Cite book|title = Coal Energy Systems|last = Miller|first = Bruce|publisher = Elsevier Science Technology|year = 2004|isbn = |location = |pages = 294–299}}</ref>
: SO<sub>2</sub>  +  Ca(OH)<sub>2</sub>   →  CaSO<sub>3</sub>  +  H<sub>2</sub>O

如果体系中存在[[氧气]]，亚硫酸根就会被氧化为[[硫酸根]]，最后可以得到二水合硫酸钙晶体，即[[石膏]]<ref>{{Cite journal|title=Experimental Investigation and Modeling of a Wet Flue Gas Desulfurization Pilot Plant|author=Søren Kiil, Michael L. Michelsen and Kim Dam-Johansen|url=http://pubs.acs.org/doi/full/10.1021/ie9709446|journal=Ind. Eng. Chem. Res.|issue=37|doi=10.1021/ie9709446|others=|year=1998|volume=7|page=2792–2806|pmid=}}</ref>。

实验室制法则是令[[氯化鈣]]水溶液与[[亚硫酸钠]]水溶液反应：

: CaCl<sub>2</sub>  +  Na<sub>2</sub>SO<sub>3</sub>   →   CaSO<sub>3 </sub> +  2 NaCl

== 结构 ==
亚硫酸钙的结构已由[[X射线晶体学]]检验得出<ref>{{cite journal|title=Crystal structure of calcium sulfite|authors=Yasue, Tamotsu; Arai, Yasuo|journal=Gypsum & Lime (Jap. Language)|year=1986|volume=203|pages=235–244}}</ref>。

半水合亚硫酸钙晶体中，钙的[[配位数]]是6，每个钙离子连有五个亚硫酸根的氧原子及一个水分子中的氧原子，六个氧原子组成[[三角反棱柱]]的形状。半水合亚硫酸钙晶体热力学较稳定的原因可能是Ca－O键在整个晶体中延展形成网状结构。<ref>{{cite journal|title=The crystal structure of calcium sulfite hemihydrate|authors=Matsuno, Takashi; Takayanagi, Hiroaki; Furuhata, Kimio; Koishi, Masumi; Ogura, Haruo|journal= Bulletin of the Chemical Society of Japan|year=1984|volume=57|issue=2|pages=1155-1156|doi=10.1246/bcsj.57.1155}}</ref>

四水合亚硫酸钙只在低温下稳定，在室温下会迅速转变为半水合物，因此获得四水合物[[单晶]]并分析结构较为困难。不过，使用[[琼脂]]制造溶胶环境即可减慢反应物分子的速度，便于结晶，从而制得晶体。<ref>{{cite journal|title=The Crystal Structure of Calcium Sulfite Tetrahydrate|journal=Chemistry Letters|issue=4|doi=10.1246/cl.1983.459|year=1983|volume=12|pages=459-462|authors=Matsuno, Takashi; Takayanagi, Hiroaki; Furuhata, Kimio; Koishi, Masumi; Ogura, Haruo}}</ref>四水合亚硫酸钙晶体中钙的配位数同样为6，两个氧原子来自亚硫酸根，四个来自水分子。其热力学不稳定的原因可能是其中的亚硫酸根离子处于无序状态。<ref>{{cite journal|title=The Crystal Structure of Calcium Sulfite Tetrahydrate. Interatomic Distances and Angles|url=https://archive.org/details/sim_bulletin-of-the-chemical-society-of-japan_1984-02_57_2/page/593|authors=Matsuno, Takashi; Takayanagi, Hiroaki; Furuhata, Kimio; Koishi, Masumi; Ogura, Haruo|journal= Bulletin of the Chemical Society of Japan|year=1984|volume=57|issue=2|pages=593-594|doi=10.1246/bcsj.57.593}}</ref>

== 参见 ==
* [[亚硫酸盐]]
* [[亚硫酸镁]]
* [[亚硫酸钠]]
* [[亚硫酸氢钠]]
* [[焦亚硫酸钠]]
* {{tsl|en|Campden tablet|坎普登片剂|}}

== 参考文献 ==
{{reflist|30em}}

{{鈣化合物}}
{{亚硫酸盐}}

[[Category:钙化合物]]
[[Category:亚硫酸盐]]
[[Category:缺少物质图片的化学品条目]]
[[Category:有E编码的食品添加剂]]