<p><b>連二亞硫酸鹽</b> ([S<sub>2</sub>O<sub>4</sub>]<sup>2−</sup>)是一種硫的<span data-orig-title="含氧酸盐" data-lang-code="en" data-lang-name="英語" data-foreign-title="Oxyanion"><span>含氧酸鹽</span></span>。連二亞硫酸鹽的例子有連二亞硫酸鈉和連二亞硫酸鋅。</p>
<h2><span id=".E5.8F.8D.E5.BA.94"></span><span id="反应">反應</span></h2>
<p>連二亞硫酸鹽是一種還原劑，會還原成亞硫酸鹽：</p>
<dl><dd><span>S<span><br>2</span>O<span>2−<br>4</span></span>  +  2 H<sub>2</sub>O   →   2 <span>HSO<span>−<br>3</span></span>  +  2 e<sup>−</sup> +  2 H<sup>+</sup></dd></dl><p>連二亞硫酸鹽水解歧化成硫代硫酸鹽和亞硫酸氫鹽：</p>
<dl><dd>2 <span>S<span><br>2</span>O<span>2−<br>4</span></span> + H<sub>2</sub>O → <span>S<span><br>2</span>O<span>2−<br>3</span></span> + 2 <span>HSO<span>−<br>3</span></span></dd></dl><p>在鹼的作用下歧化成亞硫酸鹽和硫化物：</p>
<dl><dd>3 S<sub>2</sub>O<sub>4</sub><sup>2-</sup> + 6 OH<sup>-</sup> → 5 SO<sub>3</sub><sup>2-</sup> + S<sup>2-</sup> + 3 H<sub>2</sub>O</dd></dl><p>它是連二亞硫酸 (H<sub>2</sub>S<sub>2</sub>O<sub>4</sub>)的鹽，不過這種酸沒有實際用途。
</p>
<h2><span id=".E5.8F.82.E8.80.83.E8.B5.84.E6.96.99"></span><span id="参考资料">參考資料</span></h2>

<ul><li><cite class="citation book">Greenwood, N. N.; Earnshaw, A. <span></span><i>Chemistry of the Elements</i><span></span> 2nd. Oxford:Butterworth-Heinemann. 1997. <span title="國際標準書號">ISBN</span> 0-7506-3365-4.</cite><span title="ctx_ver=Z39.88-2004&amp;rfr_id=info%3Asid%2Fzh.wikipedia.org%3A%E8%BF%9E%E4%BA%8C%E4%BA%9A%E7%A1%AB%E9%85%B8%E7%9B%90&amp;rft.au=Earnshaw%2C+A.&amp;rft.au=Greenwood%2C+N.+N.&amp;rft.btitle=Chemistry+of+the+Elements&amp;rft.date=1997&amp;rft.edition=2nd&amp;rft.genre=book&amp;rft.isbn=0-7506-3365-4&amp;rft.pub=Oxford%3AButterworth-Heinemann&amp;rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook"><span> </span></span></li></ul><!-- 
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**連二亞硫酸鹽** ([S2O4]2−) 是一種硫的含氧酸鹽。連二亞硫酸鹽的例子有連二亞硫酸鈉和連二亞硫酸鋅。

## 反應

連二亞硫酸鹽是一種還原劑，會還原成亞硫酸鹽：

　
: S 
2O2− 
4 + 2 H2O → 2 HSO− 
3 + 2 e− + 2 H+

連二亞硫酸鹽水解歧化成硫代硫酸鹽和亞硫酸氫鹽：

　
: 2 S 
2O2− 
4 + H2O → S 
2O2− 
3 + 2 HSO− 
3

在鹼的作用下歧化成亞硫酸鹽和硫化物：

　
: 3 S2O42- + 6 OH- → 5 SO32- + S2- + 3 H2O

它是連二亞硫酸 (H2S2O4) 的鹽，不過這種酸沒有實際用途。

## 參考資料

* Greenwood, N. N.; Earnshaw, A. _Chemistry of the Elements_ 2nd. Oxford:Butterworth-Heinemann. 1997. ISBN 0-7506-3365-4.
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