磷酸亞鐵

磷酸亞鐵是磷酸的鐵鹽，化學式Fe₃(PO₄)₂。它在自然界中以藍鐵礦形式存在^[7]，可用作肥料。^[8]

磷酸亞鐵
IUPAC名 Iron(II) phosphate
別名	磷酸鐵(II)
識別
CAS號	14940-41-1  Y
PubChem	9863567
ChemSpider	8039263
SMILES	[O-]P(=O)([O-])[O-].[O-]P(=O)([O-])[O-].[Fe+2].[Fe+2].[Fe+2]
性質
化學式	Fe3O8P2
摩爾質量	357.48 g·mol−1
外觀	無色固體[1] 藍灰色晶體（八水）[2]
密度	3.94 g/cm3[3] 2.58 g/cm3（八水合物）[4]
熔點	180 °C（453 K）（（八水合物）分解[6]）
溶解性（水）	不溶（八水）[5]
溶解性	不溶於乙醇，可溶於酸（八水）[5]
若非註明，所有數據均出自標準狀態（25 ℃，100 kPa）下。

製備

磷酸亞鐵可以由硫酸亞鐵和磷酸鈉溶液反應而成：^[1]

3 FeSO₄ + 2 Na₃PO₄ → Fe₃(PO₄)₂↓ + 3 Na₂SO₄

磷酸和鐵直接反應只會得到Fe(H₂PO₄)₂·2H₂O^[1]。無水磷酸亞鐵可以由硝酸鐵和磷酸二氫銨反應，然後加熱產生的棕色物質而成。^[7]

物理性質

無水磷酸亞鐵呈單斜晶系，空間群P2₁/c (No. 14)。^[3]其四水合物和八水合物的晶體結構也是單斜晶系，空間群分別為P2₁/a (No. 14)和C2/m (No. 12)。^[9][10][11]

剛沉澱產生的八水合磷酸亞鐵是藍灰色固體，在空氣氧化下轉變成靛藍色。對其進一步氧化會破壞其晶體結構，產生黃棕色的無定形體。^[8]

化學性質

• 與磷酸反應，形成酸式鹽：

${\displaystyle {\mathsf {Fe_{3}(PO_{4})_{2}+H_{3}PO_{4}\ {\xrightarrow {}}\ 3FeHPO_{4}}}}$

${\displaystyle {\mathsf {Fe_{3}(PO_{4})_{2}+4H_{3}PO_{4}\ {\xrightarrow {}}\ 3Fe(H_{2}PO_{4})_{2}}}}$

• 與氫反應生成磷化物：

${\displaystyle {\mathsf {Fe_{3}(PO_{4})_{2}+8H_{2}\ {\xrightarrow {T}}\ Fe_{3}P_{2}+8H_{2}O}}}$

• 水合物加熱分解：

${\displaystyle {\mathsf {Fe_{3}(PO_{4})_{2}\cdot 8H_{2}O\ {\xrightarrow[{-H_{2}O}]{T}}\ Fe_{3}(PO_{4})_{2}\cdot 4H_{2}O\ {\xrightarrow[{-H_{2}O}]{180^{o}C}}\ Fe_{3}(PO_{4})_{2}}}}$

磷酸亞鐵可以和N₂H₄形成各種配合物，如深綠色的Fe₃(PO₄)₂·3N₂H₄·5H₂O^[12]、白色的Fe₃(PO₄)₂·6N₂H₄·2.75H₂O、^[13]淺綠色的Fe₃(PO₄)₂·6N₂H₄·8H₂O^[14]以及白色的Fe₃(PO₄)₂·7N₂H₄·nH₂O。^[12]它們都會爆炸。

參見

• 磷酸鐵

參考

1. Eisenphosphate Lexikon der Chemie. [2022-11-22]. （原始內容存檔於2022-11-22）.
2. CRC Handbook of Chemistry and Physics, 95 ed. CRC Press, 2014
3. Kostiner, E.; Rea, J. R. Crystal structure of ferrous phosphate, Fe3(PO4)2. Inorganic Chemistry (American Chemical Society (ACS)). 1974, 13 (12): 2876–2880. ISSN 0020-1669. doi:10.1021/ic50142a021.
4. Jan D'Ans; Ellen Lax; Blachnik, Roger. Taschenbuch für Chemiker und Physiker : Band III: Elemente, anorganische Verbindungen und Materialien, Minerale. Berlin, Heidelberg. 2013: 458. ISBN 978-3-642-58842-6. OCLC 913685219 （德語）.
5. Hunnius, Curt; Burger, Artur. Hunnius pharmazeutisches Wörterbuch. Berlin. 2020: 469. ISBN 978-3-11-086901-9. OCLC 1138499573 （德語）.
6. iron(II) phosphate octahydrate. chemister.ru. [2 July 2014]. （原始內容存檔於2014-05-03）.
7. Warner, Joanne K.; Cheetham, Anthony K.; Nord, Anders G.; Von Dreele, Robert B.; Yethiraj, Mohana. Magnetic structure of iron(II) phosphate, sarcopside, Fe3(PO4)2. Journal of Materials Chemistry (Royal Society of Chemistry (RSC)). 1992, 2 (2): 191. ISSN 0959-9428. doi:10.1039/jm9920200191.
8. Eynard, A.; Campillo, M. C.; Barrón, V.; Torrent, J. Use of vivianite (Fe3(PO4)2.8H2O) to prevent iron chlorosis in calcareous soils. Fertilizer Research (Springer Science and Business Media LLC). 1992, 31 (1): 61–67. ISSN 0167-1731. doi:10.1007/bf01064228.
9. Abrahams, S. C.; Bernstein, J. L. Crystal Structure of Paramagnetic Ludlamite, Fe3(PO4)2·4H2O, at 298°K. The Journal of Chemical Physics (AIP Publishing). 1966-03-15, 44 (6): 2223–2229. ISSN 0021-9606. doi:10.1063/1.1727026.
10. Meijer, H.C.; Van den Handel, J.; Frikkee, E. Magnetic behaviour of vivianite, Fe3(PO4)2.8H2O. Physica (Elsevier BV). 1967, 34 (3): 475–483. ISSN 0031-8914. doi:10.1016/0031-8914(67)90015-8.
11. Bartl, H. Water of crystallization and its hydrogen-bonded crosslinking in vivianite Fe3(PO4)2 · 8H2O; a neutron diffraction investigation. Fresenius' Zeitschrift für analytische Chemie (Springer Science and Business Media LLC). 1989, 333 (4-5): 401–403. ISSN 0016-1152. doi:10.1007/bf00572335.
12. British Library. Lending Division, Royal Society of Chemistry (Great Britain), Chemical Society (Great Britain), Akademii︠a︡ nauk SSSR. Russian Journal of Inorganic Chemistry, Volume 32, Pages 919-1821. British Library Lending Division with the cooperation of the Royal Society of Chemistry. 1987: 973 [2022-11-22]. （原始內容存檔於2022-11-22）.
13. British Library. Lending Division, Royal Society of Chemistry (Great Britain), Chemical Society (Great Britain), Akademii︠a︡ nauk SSSR. Russian Journal of Inorganic Chemistry, Volume 27, Pages 1-913. British Library Lending Division with the cooperation of the Royal Society of Chemistry. 1982: 831 [2022-11-22]. （原始內容存檔於2022-11-22）.
14. British Library. Lending Division, Royal Society of Chemistry (Great Britain), Chemical Society (Great Britain), Akademii︠a︡ nauk SSSR. Russian Journal of Inorganic Chemistry, Volume 32, Pages 919-1821. British Library Lending Division with the cooperation of the Royal Society of Chemistry. 1987: 974 [2022-11-22]. （原始內容存檔於2022-11-22）.

延伸閱讀

• Редкол.: Кнунянц И.Л. и др. (編). Химическая энциклопедия. 2. М.: Советская энциклопедия. 1990: 671. ISBN 5-82270-035-5.
• Редкол.: Никольский Б.П. и др. (編). Справочник химика. 1 2-е изд., испр. М.-Л.: Химия. 1966: 1072.
• Редкол.: Никольский Б.П. и др. (編). Справочник химика. 2 3-е изд., испр. Л.: Химия. 1971: 1168.
• Рипан Р., Четяну И. Неорганическая химия. Химия металлов. 2. М.: Мир. 1972: 871.