鐵(VI)酸鹽

鐵酸鹽
	IUPAC名; Ferrate(VI)
	系統名; Tetraoxoironbis(olate)[來源請求]
別名	鐵酸鹽
識別
CAS編號	16836-06-9
PubChem	25000034
ChemSpider	21865127
SMILES	[O-][Fe]([O-])(=O)=O;
InChI	1/Fe.4O/q;;;2*-1/rFeO4/c2-1(3,4)5/q-2;
InChIKey	XGBDPAYTQGQHEW-WTZHFVRHAI
ChEBI	30992
性質
化學式	FeO42-
莫耳質量	119.843 g mol-1 g·mol⁻¹
	若非註明，所有數據均出自標準狀態（25 ℃，100 kPa）下。

鐵酸鹽的鐵酸根是無機陰離子，化學式[FeO₄]²⁻。它對光敏感，其化合物和溶液呈淡紫色，為已知對水穩定的極強氧化劑。儘管歸為弱鹼，鐵酸鹽濃溶液仍有腐蝕性，且會燒傷皮膚，只能在強鹼環境穩定存在。

命名法

ferrate通常指代鐵酸根，但也可以指其它含鐵陰離子，當中許多比[FeO₄]²⁻鹽常見。這包括有強還原性的四羰基鐵酸二鈉Na₂[Fe(CO)₄]和三價鐵錯合物四氯鐵酸根[FeCl₄]⁻。鐵的含氧陰離子鐵(V)酸根[FeO₄]³⁻和鐵(IV)酸根[FeO₄]⁴⁻也同樣存在，但其研究較少。這些也稱為鐵酸根。^[1]

合成

鐵酸鹽可在鹼性條件用強氧化劑在水溶液中氧化鐵，或加熱固態的鐵屑和粉狀硝酸鉀的混合物而形成。^[2]

如在鹼性溶液加熱氫氧化鐵與次氯酸鈉製備鐵酸鹽：^[3]

2Fe(OH)₃＋3OCl⁻＋4OH⁻　→　2[FeO₄]²⁻＋5H₂O＋3Cl⁻

通常讓陰離子以鋇鹽形式沉澱出來，形成鐵酸鋇。^[3]

性質

鐵酸根離子不穩定，在中性^[2]或酸性環境會分解為三價鐵：^[3]

[FeO₄]²⁻＋3e⁻＋8H⁺　⇌　Fe³⁺＋4H₂O

還原過程中間體中鐵的氧化態有+5和+4^[4]。這些陰離子甚至比鐵酸根活潑^[5]。鐵酸根在鹼性條件更穩定，酸值為8或9時能存在8至9小時^[5]。

稀鐵酸鹽水溶液為粉紅色，濃時為深紅或紫色^[4]^[6]。與過錳酸鹽相比，鐵酸鹽是更強的氧化劑^[7]，可將三價鉻氧化成重鉻酸鹽^[8]，或將氨氧化成氮分子^[9]。

鐵酸鹽是優秀的消毒劑，能移除並殺死病毒。^[10]

鐵酸根離子有兩個不成對電子，有順磁性。其為四面體形分子構型。^[4]

參見

鐵酸鉀

參考資料

^ Graham Hill; John Holman. Chemistry in context 5th. Nelson Thornes. 2000: 202. ISBN 0-17-448276-0.
^ ^2.0 ^2.1 R. K. Sharma. Text Book Of Coordination Chemistry. Discovery Publishing House. 2007: 124–125. ISBN 81-8356-223-X.
^ ^3.0 ^3.1 ^3.2 Gary Wulfsberg. Principles of descriptive inorganic chemistry. University Science Books. 1991: 142–143. ISBN 0-935702-66-0.
^ ^4.0 ^4.1 ^4.2 Egon Wiberg; Nils Wiberg; Arnold Frederick Holleman. Inorganic chemistry. Academic Press. 2001: 1457–1458. ISBN 0-12-352651-5.
^ ^5.0 ^5.1 Gary M. Brittenham. Raymond J. Bergeron , 編. The Development of Iron Chelators for Clinical Use. CRC Press. 1994: 37–38. ISBN 0-8493-8679-9.
^ John Daintith (編). Oxford dictionary of chemistry 5th. Oxford University Press. 2004: 235. ISBN 0-19-860918-3.
^ Kenneth Malcolm Mackay; Rosemary Ann Mackay; W. Henderson. Introduction to modern inorganic chemistry 6th. CRC Press. 2002: 334–335. ISBN 0-7487-6420-8.
^ Amit Arora. Text Book Of Inorganic Chemistry. Discovery Publishing House. 2005: 691–692. ISBN 81-8356-013-X.
^ Karlis Svanks. Oxidation of Ammonia in Water by Ferrates(VI) and (IV) (PDF). Water Resources Center, Ohio State University: 3. June 1976 [2010-05-04].
^ Stanley E. Manahan. Environmental chemistry 8th. CRC Press. 2005: 234. ISBN 1-56670-633-5.

[hill-1] Graham Hill; John Holman. Chemistry in context 5th. Nelson Thornes. 2000: 202. ISBN 0-17-448276-0.

[sharma-2] 2.0 ^2.1 R. K. Sharma. Text Book Of Coordination Chemistry. Discovery Publishing House. 2007: 124–125. ISBN 81-8356-223-X.

[wulfsberg-3] 3.0 ^3.1 ^3.2 Gary Wulfsberg. Principles of descriptive inorganic chemistry. University Science Books. 1991: 142–143. ISBN 0-935702-66-0.

[wiberg-4] 4.0 ^4.1 ^4.2 Egon Wiberg; Nils Wiberg; Arnold Frederick Holleman. Inorganic chemistry. Academic Press. 2001: 1457–1458. ISBN 0-12-352651-5.

[bergeron-5] 5.0 ^5.1 Gary M. Brittenham. Raymond J. Bergeron , 編. The Development of Iron Chelators for Clinical Use. CRC Press. 1994: 37–38. ISBN 0-8493-8679-9.

[6] John Daintith (編). Oxford dictionary of chemistry 5th. Oxford University Press. 2004: 235. ISBN 0-19-860918-3.

[mackay-7] Kenneth Malcolm Mackay; Rosemary Ann Mackay; W. Henderson. Introduction to modern inorganic chemistry 6th. CRC Press. 2002: 334–335. ISBN 0-7487-6420-8.

[8] Amit Arora. Text Book Of Inorganic Chemistry. Discovery Publishing House. 2005: 691–692. ISBN 81-8356-013-X.

[9] Karlis Svanks. Oxidation of Ammonia in Water by Ferrates(VI) and (IV) (PDF). Water Resources Center, Ohio State University: 3. June 1976 [2010-05-04].

[10] Stanley E. Manahan. Environmental chemistry 8th. CRC Press. 2005: 234. ISBN 1-56670-633-5.

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