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Iron Oxide

Crystal: FeO

Structure: NaCl

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Mechanical and structural properties:

FeO and Fe₂O₃are insulators; Fe₃O₄ can be semiconducting

Cohesive energy:	eV
Lattice parameter:	2.14 Å
Density:	5.18 g/cm³

Stiffness constants: in 10¹¹ dynes/cm², at room temperature

c₁₁: 35.9 (neutron data; Ref.1)

c₁₂: 15.6

c₄₄: 5.63

Compressibility (in 10¹¹ dynes/cm²): 0.0447 ??

Poisson ratio:

Debye temperature: K

Melting temperature: 1420 ° C

Neel temperature: 198 K

Phonon spectrum discussed by:

Transverse optic phonon T0 (k=0): 333.7 cm^-1 (Ref.2), n: 320, IR: 290

Longitude optic phonon L0 (k=0): 493.7 cm^-1 , n: 526, IR 535

Gruneissen constant:

Ratio e*/e:

Photoelastic constants:

p₁₁:

p₁₂:

p₄₄:

Electronic properties:

Band gap:

direct: eV.

indirect: eV.

Gap: eV.

First exciton: eV.

Photoemission for FeO, CoO, NiO:

Deduce values of Delta.

FeO D = 1.5/1.7 eV Fe3+ high spin

CoO -1.8 eV Co3+ low spin

NiO -1.7 eV Ni3+ low spin

Ref:

G. Grenet et al., On the interpretation of 3dN ion photoemission spectra. I: A comparative study of the valence band of FeO, CoO, and NiO, J Chem. Phys. 74, 2163 (1981)

Band structure discussed: Phys. Rev. B16, 900 (1977)

Static dielectric constant: 12.7-14.2 or 24 (Ref.2) or 32.8 (Ref.1)

Optic dielectric constant: or 11.1 or 9.63

m = 2.0 (Winchell & Winchell)

e (¥ )= 4.0

Electron mobility:

Hole mobility:

Polaron coupling constant: a = ( for m*=1 )

Effective mass: conduction band:

valence band:

Electron affinity: ( in eV., from bottom of conduction band under vacuum)

Spin-orbit coupling: ( valence band)

Cation polarisation: Å^-3

Anion polarisation: Å^-3

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Other information:

At 36 Kbar, 770 ° C, FeO is stoichiometric. See: J. Phys. Chem. Ref. Data 6, 1205 (1977)

At 3500K., FeO is unstable: H. Schmalzried, Reactivity and point defects of double oxides with emphasis on simple silicates, Phys. Chem. Min. 2, 297 (1978)

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References:

1. G. Kugel, C. Carabatos, B. Hennion, B. Prevot, Lattice dynamics of Wustite (FeO), Phys. Rev. B16, 378 (1977)

2. R.V. Pisarev, V.V. Druzhinin, N.N. Nesterova, Optical absorption of ferroelectrical iron boracites, Phys. Stat. Sol. 40, 503 (1977)

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