一氢化铁

一氢化铁
	IUPAC名; Iron(I) hydride
	系统名; Hydridoiron(3•)
识别
CAS号	15600-68-7
SMILES	[Fe][H];
性质
化学式	FeH3•
摩尔质量	56.853 g·mol⁻¹
热力学
ΔfHm⦵298K	450.6 kJ·mol−1[來源請求]
相关物质
相关化学品	氢化铁，氢化亚铁; 氢化铬，氢化钙，氢化镁
	若非注明，所有数据均出自标准状态（25 ℃，100 kPa）下。

一氢化铁是由铁和氢形成的化合物，化学式为FeH。仅在极端环境中才检测到单独存在的一氢化铁，如在低温稀有气体中，在冷恒星的大气层中，或在高于铁沸点的温度以气体的形式存在。它被假定为具有三个悬空的价键，因此是一种自由基；其通式可以写成FeH^2•以强调这一事实。

在极端低温下（低于10 K），FeH可以与分子氢形成配合物FeH·H₂^[1]。

一氢化铁是几种已知的铁和氢气的化合物之一，都同样罕见；其中还包括只在极端低温下才能稳定存在的氢化亚铁（FeH₂），及一种高压铁氢合金，化学式也为FeH。

20世纪50年代，科尔曼和L. Åkerlind首先在实验室检测到了一氢化铁。^{[來源請求]}

在外层空间中存在编辑

一氢化铁是在太阳中发现的几种分子之一^[2]。1972年有研究报告了太阳光谱中代表FeH的蓝绿线，同时还报告了许多吸收线^[3]。同样黑子的数量也突出了荣福特带^[4]。

FeH（及其他过渡金属和碱土金属的氢化物）的光谱带出现在M矮星和L矮星发射光谱的显著位置上，其为最热的一种褐矮星。对于较冷的L矮星，FeH的光谱带没有出现^[5]，这可能是由于液态铁云阻挡了大气中的视线，并且从大气的气相中除掉了它。对于更冷的褐矮星（<1350 K），FeH的信号再次出现，这可以用云层中存在间隙来解释^[6]。

恒星出现FeH荣福特带的原因是，其约为3000 K的温度和适当的压强足以形成大量FeH分子。如在K矮星中，一旦温度达到4000 K谱线就更弱，因为更多的分子被分解掉了。在红巨星M巨星中，气压太低以至于FeH无法形成^[7]。

因为存在着大量的M矮星，椭圆和透镜星系也有可以观测到的荣福特带^[4]。

制备编辑

科尔曼和Åkerlind用王式炉在薄氢气氛中加热铁至2600 K，首次在实验室中制得FeH。

分子FeH（连同FeH₂和其他物质）也可以通过在氩氢气氛中加热铁至沸腾，并在约10 K（-263 °C）的固体表面上凝结气体得到。该化合物可以通过红外吸收光谱法进行检测，而当样品被快速加热至30 K时出现了一半的损失^[8]。一种变体技术使用的是在4 K下凝结的纯氢气氛^[1]。

该过程还会生成被认为是FeH₃（氢化铁）的分子，但后来则认为其由FeH和分子氢H₂组成^[9]。

FeH分子可由嵌入固态氢的⁵⁷Co衰变而形成。穆斯堡尔谱学显示，与2.4 mm/s的金属铁和四极分裂相比，其有0.59 mm/s的同质异能移^[10]。FeH也可以由五羰基铁蒸汽和氢原子在微波放电条件下反应而成^[11]。

结构编辑

FeH预计将有一个四重峰和一个六重峰基态。

FeH分子有至少四个由非成键电子占据不同的轨道位置而产生的低能电子态：X⁴Δ、a⁶Δ b⁶Π^[12]，和c⁶Σ⁺^[13]。较高的能态称为B⁴Σ^-、C⁴Φ、D⁴Σ⁺、E⁴Π和F⁴Δ^[14]。比这更高的能级则标记为四重峰系统的G⁴Π和H⁴Δ，及d⁶Σ^-、e⁶Π、f⁶Δ和g⁶Φ^[12]。四重峰态内量子数J可取1/2、3/2、5/2、7/2。

光谱编辑

带名	波长 nm	波数 cm^-1	跃迁
荣福特	989.6	10100	F⁴Δ—X⁴Δ
蓝	490	20408	g⁶Φ—a⁶Δ
绿	530	18867	e⁶Π—a⁶Δ

FeH在近红外区有一个重要的吸收带，称为荣福特带，带边缘位于989.652 nm处，在991 nm处吸收达到最大^[15]。它还有在470至502.5 nm的蓝色谱线和520至540 nm的绿色谱线^[3]。

与FeH在此波段相比，氘化物FeD有一个小的同位素位移，表明该带是从基态(0,0)跃迁形成，即F⁴Δ—X⁴Δ^[7]。

频谱中存在于各个位置的其他各频带则是由不同的振动跃迁形成^[4]。同样源于F⁴Δ—X⁴Δ跃迁的(1,0)带大约在869.0 nm周围，而(2,0)带则在781.8 nm附近^[14]。

每个频带都有大量的谱线。这是不同的旋转状态之间发生了跃迁。谱线分为子带⁴Δ_7/2—⁴Δ_7/2（最强）及⁴Δ_5/2—⁴Δ_5/2、⁴Δ_3/2—⁴Δ_3/2和⁴Δ_1/2—⁴Δ_1/2。像7/2的数字是自旋分量的Ω值^[4]。它们都有两个分支P和R，一些还有Q支。每个中都有所谓的Λ分裂，结果得到了一个较低的能量线（表示为“a”）和较高的能量线（称为“b”）。这一系列的谱线由J和转动量子数决定，从3.5开始持续向上增长，步长为1。J的最高取值取决于温度。此外，还有12个卫星分支⁴Δ_7/2—⁴Δ_5/2、⁴Δ_5/2—⁴Δ_3/2、⁴Δ_3/2—⁴Δ_1/2、⁴Δ_5/2—⁴Δ_7/2、⁴Δ_3/2—⁴Δ_5/2及带P和R支的⁴Δ_1/2—⁴Δ_3/2^[15]。

有些谱线对磁敏感，如994.813和995.825 nm。它们因塞曼效应而扩大，而同一个频段的其它谱线则对磁场不敏感，如994.911和995.677 nm^[16]。有在(0-0)带频谱的222线^[17]。

参见编辑

参考编辑

^ ^1.0 ^1.1 Xuefeng Wang and Lester Andrews (2009), "Infrared Spectra and Theoretical Calculations for Fe, Ru, and Os Metal Hydrides and Dihydrogen Complexes". The Journal of Physical Chemistry A, volume 113, issue 3, pages 551–563 issn:1089-5639 doi:10.1021/jp806845h
^ Sinha, K. Molecules in the sun. Proceedings of the Astronomical Society of Australia (Astronomical Society of Australia). 1991, 9 (1): 32. Bibcode:1991PASAu...9...32S. about 11 different molecules
^ ^3.0 ^3.1 Carroll, P. K.; P. McCormack. The Spectrum of FeH: Laboratory and Solar Identification. Astrophysical Journal Letters. 1972-10-01, 177: L33–L36 [2014-07-01]. Bibcode:1972ApJ...177L..33C. doi:10.1086/181047. （原始内容存档于2022-04-26）.
^ ^4.0 ^4.1 ^4.2 ^4.3 Schiavon, Ricardo P.; B. Barbuy; Patan D. Singh. The FeH Wing-Ford Band in Spectra of M Stars. The Astrophysical Journal (The American Astronomical Society). 1997-07-20, 484: 499–510. Bibcode:1997ApJ...484..499S. arXiv:astro-ph/9701186  . doi:10.1086/304332.
^ Cowen, Ron. So cool, and some are still stars. Science News. 1998-07-04. ^{[永久失效連結]}
^ Burgasser, Adam J.; Mark S. Marley; Andrew S. Ackerman; Didier Saumon; Katharina Lodders; Conard C. Dahn; Hugh C. Harris; J. Davy Kirkpatrick. Evidence of cloud disruption in the L/T dwarf transition (PDF). The Astrophysical Journal. 2002-06-01, 571 (2): L151–L154. Bibcode:2002ApJ...571L.151B. arXiv:astro-ph/0205051  . doi:10.1086/341343.
^ ^7.0 ^7.1 Nordh, H. L.; Lindgren; Wing; Lindgren, B., & Wing, R. F. A proposed identification of FeH in the spectra of M dwarfs and S stars. Astronomy and Astrophysics. April 1977, 56 (1–2): 1–6 [2012-04-21]. Bibcode:1977A&A....56....1N. （原始内容存档于2021-08-06）.
^ George V. Chertihin and Lester Andrews (1995), "Infrared spectra of FeH, FeH₂, and FeH₃ in solid argon". Journal of Physical Chemistry, volume 99, issue 32, pages 12131–12134 doi:10.1021/j100032a013
^ Andrews, Lester. Matrix infrared spectra and density functional calculations of transition metal hydrides and dihydrogen complexes. Chemical Society Reviews. 2004-01-30, 33 (2): 123–132 [2013-02-02]. PMID 14767507. doi:10.1039/B210547K.
^ Pasternak, M.; M. Van Der Heyden and G. Langouche. The characterization of FeH molecules by Mössbauer spectroscopy. Chemical Physics Letters. February 1984, 104 (4): 398–400. Bibcode:1984CPL...104..398P. doi:10.1016/0009-2614(84)80087-1.
^ Brown, John M.; Helga Körsgen, Stuart P. Beaton and Kenneth M. Evenson. The rotational and fine-structure spectrum of FeH, studied by far-infrared laser magnetic resonance. The Journal of Chemical Physics (American Institute of Physics). 2006, 124 (23): 234309. Bibcode:2006JChPh.124w4309B. doi:10.1063/1.2198843.
^ ^12.0 ^12.1 Hullah, Daniel F.; Richard F. Burrow and John M. Brown. Low-lying energy levels of the FeH molecule. Molecular Physics. September 1999, 97 (1–2): 93–103. doi:10.1080/00268979909482812.
^ Goodridge, Damian M.; Daniel F. Hullah; John M. Brown. Rotational analysis and assignment of the 630 nm band system of FeH to the e 6Π–c 6Σ1 transition. Journal of Chemical Physics. 1998-01-08, 108 (2): 428–435. Bibcode:1998JChPh.108..428G. doi:10.1063/1.475404.
^ ^14.0 ^14.1 Ram, R. S.; P. F. Bernath and S. P. Davis. Fourier Transform Emission Spectroscopy of the g4Δ–a4Δ System of FeF (PDF). Journal of Molecular Spectroscopy. 1996-05-10, 179 (2): 297 [2014-07-01]. Bibcode:1996JMoSp.179..282R. doi:10.1006/jmsp.1996.0207. （原始内容 (PDF)存档于2005-03-10）.
^ ^15.0 ^15.1 Phillips, J. G.; S. P. Davis, B. Lindgren,and W. J. Balfour,. The near-infrared spectrum of the FeH molecule. Astrophysical Journal Supplement Series. December 1987, 65: 721–778 [2014-07-01]. Bibcode:1987ApJS...65..721P. ISSN 0067-0049. doi:10.1086/191241. （原始内容存档于2021-03-24）.
^ Reiners, A.; J. H. M.M. Schmitt, and C. Liefke. Rapid magnetic flux variability on the flare star CN Leonis (PDF). Astronomy and Astrophysics. 2007, 466 (2): L13–L16 [2014-07-01]. Bibcode:2007A&A...466L..13R. arXiv:astro-ph/0703172  . doi:10.1051/0004-6361:20077095. （原始内容存档 (PDF)于2022-03-23）.
^ John S. Mulchaey. The Rotational Temperature of the FeH Molecule in a Sunspot. Publications of the Astronomical Society of the Pacific (The University of Chicago Press). February 1989, 101 (636): 211–214. Bibcode:1989PASP..101..211M. JSTOR 40679297. doi:10.1086/132424.

扩展阅读编辑

FeH Bibliography （页面存档备份，存于互联网档案馆），来自ExoMol

[Wang2009-1] 1.0 ^1.1 Xuefeng Wang and Lester Andrews (2009), "Infrared Spectra and Theoretical Calculations for Fe, Ru, and Os Metal Hydrides and Dihydrogen Complexes". The Journal of Physical Chemistry A, volume 113, issue 3, pages 551–563 issn:1089-5639 doi:10.1021/jp806845h

[Sinhak-2] Sinha, K. Molecules in the sun. Proceedings of the Astronomical Society of Australia (Astronomical Society of Australia). 1991, 9 (1): 32. Bibcode:1991PASAu...9...32S. about 11 different molecules

[Carrol-3] 3.0 ^3.1 Carroll, P. K.; P. McCormack. The Spectrum of FeH: Laboratory and Solar Identification. Astrophysical Journal Letters. 1972-10-01, 177: L33–L36 [2014-07-01]. Bibcode:1972ApJ...177L..33C. doi:10.1086/181047. （原始内容存档于2022-04-26）.

[Schiavon-4] 4.0 ^4.1 ^4.2 ^4.3 Schiavon, Ricardo P.; B. Barbuy; Patan D. Singh. The FeH Wing-Ford Band in Spectra of M Stars. The Astrophysical Journal (The American Astronomical Society). 1997-07-20, 484: 499–510. Bibcode:1997ApJ...484..499S. arXiv:astro-ph/9701186  . doi:10.1086/304332.

[Cowen-5] Cowen, Ron. So cool, and some are still stars. Science News. 1998-07-04. ^{[永久失效連結]}

[Burgasser-6] Burgasser, Adam J.; Mark S. Marley; Andrew S. Ackerman; Didier Saumon; Katharina Lodders; Conard C. Dahn; Hugh C. Harris; J. Davy Kirkpatrick. Evidence of cloud disruption in the L/T dwarf transition (PDF). The Astrophysical Journal. 2002-06-01, 571 (2): L151–L154. Bibcode:2002ApJ...571L.151B. arXiv:astro-ph/0205051  . doi:10.1086/341343.

[Nordh-7] 7.0 ^7.1 Nordh, H. L.; Lindgren; Wing; Lindgren, B., & Wing, R. F. A proposed identification of FeH in the spectra of M dwarfs and S stars. Astronomy and Astrophysics. April 1977, 56 (1–2): 1–6 [2012-04-21]. Bibcode:1977A&A....56....1N. （原始内容存档于2021-08-06）.

[Chertihin-8] George V. Chertihin and Lester Andrews (1995), "Infrared spectra of FeH, FeH₂, and FeH₃ in solid argon". Journal of Physical Chemistry, volume 99, issue 32, pages 12131–12134 doi:10.1021/j100032a013

[Andrews2004-9] Andrews, Lester. Matrix infrared spectra and density functional calculations of transition metal hydrides and dihydrogen complexes. Chemical Society Reviews. 2004-01-30, 33 (2): 123–132 [2013-02-02]. PMID 14767507. doi:10.1039/B210547K.

[Pasternak-10] Pasternak, M.; M. Van Der Heyden and G. Langouche. The characterization of FeH molecules by Mössbauer spectroscopy. Chemical Physics Letters. February 1984, 104 (4): 398–400. Bibcode:1984CPL...104..398P. doi:10.1016/0009-2614(84)80087-1.

[Brown2006-11] Brown, John M.; Helga Körsgen, Stuart P. Beaton and Kenneth M. Evenson. The rotational and fine-structure spectrum of FeH, studied by far-infrared laser magnetic resonance. The Journal of Chemical Physics (American Institute of Physics). 2006, 124 (23): 234309. Bibcode:2006JChPh.124w4309B. doi:10.1063/1.2198843.

[HullahD-12] 12.0 ^12.1 Hullah, Daniel F.; Richard F. Burrow and John M. Brown. Low-lying energy levels of the FeH molecule. Molecular Physics. September 1999, 97 (1–2): 93–103. doi:10.1080/00268979909482812.

[Goodridge-13] Goodridge, Damian M.; Daniel F. Hullah; John M. Brown. Rotational analysis and assignment of the 630 nm band system of FeH to the e 6Π–c 6Σ1 transition. Journal of Chemical Physics. 1998-01-08, 108 (2): 428–435. Bibcode:1998JChPh.108..428G. doi:10.1063/1.475404.

[Ram-14] 14.0 ^14.1 Ram, R. S.; P. F. Bernath and S. P. Davis. Fourier Transform Emission Spectroscopy of the g4Δ–a4Δ System of FeF (PDF). Journal of Molecular Spectroscopy. 1996-05-10, 179 (2): 297 [2014-07-01]. Bibcode:1996JMoSp.179..282R. doi:10.1006/jmsp.1996.0207. （原始内容 (PDF)存档于2005-03-10）.

[Phillips-15] 15.0 ^15.1 Phillips, J. G.; S. P. Davis, B. Lindgren,and W. J. Balfour,. The near-infrared spectrum of the FeH molecule. Astrophysical Journal Supplement Series. December 1987, 65: 721–778 [2014-07-01]. Bibcode:1987ApJS...65..721P. ISSN 0067-0049. doi:10.1086/191241. （原始内容存档于2021-03-24）.

[Reiners-16] Reiners, A.; J. H. M.M. Schmitt, and C. Liefke. Rapid magnetic flux variability on the flare star CN Leonis (PDF). Astronomy and Astrophysics. 2007, 466 (2): L13–L16 [2014-07-01]. Bibcode:2007A&A...466L..13R. arXiv:astro-ph/0703172  . doi:10.1051/0004-6361:20077095. （原始内容存档 (PDF)于2022-03-23）.

[Mulcha-17] John S. Mulchaey. The Rotational Temperature of the FeH Molecule in a Sunspot. Publications of the Astronomical Society of the Pacific (The University of Chicago Press). February 1989, 101 (636): 211–214. Bibcode:1989PASP..101..211M. JSTOR 40679297. doi:10.1086/132424.

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