Iron(II) selenide
Names
IUPAC name
Iron(II) selenide
Identifiers
3D model (JSmol)
ECHA InfoCard 100.013.798 Edit this at Wikidata
EC Number
  • 215-177-1
UNII
  • InChI=1S/Fe.Se
    Key: WALCGGIJOOWJIN-UHFFFAOYSA-N
  • [Fe]=[Se]
Properties
FeSe
Molar mass 134.807 g/mol
Appearance black crystals
Density 4.72 g/cm3
Melting point 965 °C (1,769 °F; 1,238 K)
0.975 mg/100mL[citation needed]
Structure
hexagonal / tetragonal
Hazards
Occupational safety and health (OHS/OSH):
Main hazards
 toxic
Related compounds
Other anions
 Iron(II) oxide
Iron(II) sulfide
Iron(II) telluride
Other cations
 Manganese(II) selenide
Cobalt(II) selenide
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

Iron(II) selenide refers to a number of inorganic compounds of ferrous iron and selenide (Se2−). The phase diagram of the system Fe–Se[1] reveals the existence of several non-stoichiometric phases between ~49 at. % Se and ~53 at. % Fe, and temperatures up to ~450 °C. The low temperature stable phases are the tetragonal PbO-structure (P4/nmm) β-Fe1−xSe and α-Fe7Se8. The high temperature phase is the hexagonal, NiAs structure (P63/mmc) δ-Fe1−xSe. Iron(II) selenide occurs naturally as the NiAs-structure mineral achavalite.

More selenium rich iron selenide phases are the γ phases (γ and γˈ), assigned the Fe3Se4 stoichiometry, and FeSe2, which occurs as the marcasite-structure natural mineral ferroselite, or the rare pyrite-structure mineral dzharkenite.

It is used in electrical semiconductors.[citation needed]

Superconductivity

β-FeSe is the simplest iron-based superconductor but with diverse properties.[2] It starts to superconduct at 8 K at normal pressure[3] but its critical temperature (Tc) is dramatically increased to 38 K under pressure,[4] by means of intercalation,[2] or after quenching at high pressures.[5] The combination of both intercalation and pressure results in re-emerging superconductivity at 48 K.[2]

In 2013 it was reported that a single atomic layer of FeSe epitaxially grown on SrTiO3 is superconductive with a then-record transition temperature for iron-based superconductors of 70 K.[6] This discovery has attracted significant attention and in 2014 a superconducting transition temperature of over 100K was reported for this system.[7]

References

  1. ^ Okamoto H (1991). "The Fe–Se (Iron-Selenium) System". Journal of Phase Equilibria. 12 (3): 383–389. doi:10.1007/BF02649932. S2CID 99966041.
  2. ^ a b c Yu. V. Pustovit; A. A. Kordyuk (2016). "Metamorphoses of electronic structure of FeSe-based superconductors (Review article)". Low Temp. Phys. 42 (11): 995. arXiv:1608.07751. Bibcode:2016LTP....42..995P. doi:10.1063/1.4969896. S2CID 119184569.
  3. ^ F.-C. Hsu; et al. (2008). "Superconductivity in the PbO-type structure α-FeSe". Proc. Natl. Acad. Sci. USA. 105 (38): 14262–14264. arXiv:0807.2369. Bibcode:2008PNAS..10514262H. doi:10.1073/pnas.0807325105. PMC 2531064. PMID 18776050.
  4. ^ Medvedev, S.; McQueen, T. M.; Troyan, I. A.; Palasyuk, T.; Eremets, M. I.; Cava, R. J.; Naghavi, S.; Casper, F.; Ksenofontov, V.; Wortmann, G.; Felser, C. (2009). "Electronic and Magnetic Phase Diagram of β-Fe1.01Se with superconductivity at 36.7 K under pressure". Nature Materials. 8 (8): 630–633. arXiv:0903.2143. Bibcode:2009NatMa...8..630M. doi:10.1038/nmat2491. PMID 19525948. S2CID 117714394.
  5. ^ Deng, Liangzi; Bontke, Trevor; Dahal, Rabin; Xie, Yu; Gao, Bin; Li, Xue; Yin, Ketao; Gooch, Melissa; Rolston, Donald; Chen, Tong; Wu, Zheng; Ma, Yanming; Dai, Pengcheng; Chu, Ching-Wu (13 July 2021). "Pressure-induced high-temperature superconductivity retained without pressure in FeSe single crystals". Proceedings of the National Academy of Sciences. 118 (28): e2108938118. arXiv:2104.05662. Bibcode:2021PNAS..11808938D. doi:10.1073/pnas.2108938118. PMC 8285973. PMID 34234019.
  6. ^ R. Peng; et al. (2014). "Enhanced superconductivity and evidence for novel pairing in single-layer FeSe on SrTiO3 thin film under large tensile strain". Physical Review Letters. 112 (10): 107001. arXiv:1310.3060. Bibcode:2014PhRvL.112j7001P. doi:10.1103/PhysRevLett.112.107001. PMID 24679321. S2CID 118446521.
  7. ^ J.-F. Ge; et al. (2014). "Superconductivity in single-layer films of FeSe with a transition temperature above 100 K". Nature Materials. 14 (3): 285–9. arXiv:1406.3435. Bibcode:2015NatMa..14..285G. doi:10.1038/nmat4153. PMID 25419814. S2CID 119227626.


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