iron oxide

Formula: FeO
Molecular weight: 71.844
IUPAC Standard InChI: InChI=1S/Fe.O
IUPAC Standard InChIKey: UQSXHKLRYXJYBZ-UHFFFAOYSA-N
CAS Registry Number: 1345-25-1
Chemical structure:
This structure is also available as a 2d Mol file or as a computed 3d SD file
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Other names: Iron monoxide
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Other data available:
- Condensed phase thermochemistry data
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Gas phase thermochemistry data

Go To: Top, Gas phase ion energetics data, Constants of diatomic molecules, References, Notes

Quantity	Value	Units	Method	Reference	Comment
Δ_fH°_gas	60.000	kcal/mol	Review	Chase, 1998	Data last reviewed in June, 1965
Quantity	Value	Units	Method	Reference	Comment
S°_{gas,1 bar}	57.820	cal/mol*K	Review	Chase, 1998	Data last reviewed in June, 1965

Gas Phase Heat Capacity (Shomate Equation)

C_p° = A + B*t + C*t² + D*t³ + E/t²
H° − H°_298.15= A*t + B*t²/2 + C*t³/3 + D*t⁴/4 − E/t + F − H
S° = A*ln(t) + B*t + C*t²/2 + D*t³/3 − E/(2*t²) + G
C_p = heat capacity (cal/mol*K)
H° = standard enthalpy (kcal/mol)
S° = standard entropy (cal/mol*K)
t = temperature (K) / 1000.

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View table.

Temperature (K)	5000. to 6000.
A	8.650710
B	-0.024152
C	0.154889
D	-0.016799
E	0.056932
F	57.23490
G	67.76360
H	60.00010
Reference	Chase, 1998
Comment	Data last reviewed in June, 1965

Gas phase ion energetics data

Go To: Top, Gas phase thermochemistry data, Constants of diatomic molecules, References, Notes

Data evaluated as indicated in comments:
HL - Edward P. Hunter and Sharon G. Lias

Data compiled as indicated in comments:
LBLHLM - Sharon G. Lias, John E. Bartmess, Joel F. Liebman, John L. Holmes, Rhoda D. Levin, and W. Gary Mallard
LLK - Sharon G. Lias, Rhoda D. Levin, and Sherif A. Kafafi
B - John E. Bartmess

View reactions leading to FeO⁺ (ion structure unspecified)

Quantity	Value	Units	Method	Reference	Comment
Proton affinity (review)	217.	kcal/mol	N/A	Hunter and Lias, 1998	HL
Quantity	Value	Units	Method	Reference	Comment
Gas basicity	210.4	kcal/mol	N/A	Hunter and Lias, 1998	HL

Electron affinity determinations

EA (eV)	Method	Reference	Comment
1.49450 ± 0.00022	ZEKE	Drechsler, Boesl, et al., 1997	B
1.492 ± 0.020	LPES	Engelking and Lineberger, 1977	B
1.500 ± 0.040	LPES	Wu, Desai, et al., 1996	B
1.49303	LPES	Anderson, Lykke, et al., 1987	B

Ionization energy determinations

IE (eV)	Method	Reference	Comment
8.9 ± 0.16	END	Armentrout, Halle, et al., 1982	LBLHLM
8.71 ± 0.10	EI	Hildenbrand, 1975	LLK
8. ± 1.	EI	Balducci, DeMaria, et al., 1971	LLK

Constants of diatomic molecules

Go To: Top, Gas phase thermochemistry data, Gas phase ion energetics data, References, Notes

Data compiled by: Klaus P. Huber and Gerhard H. Herzberg

Data collected through June, 1977

Symbols used in the table of constants
Symbol	Meaning
State	electronic state and / or symmetry symbol
T_e	minimum electronic energy (cm^-1)
ω_e	vibrational constant – first term (cm^-1)
ω_ex_e	vibrational constant – second term (cm^-1)
ω_ey_e	vibrational constant – third term (cm^-1)
B_e	rotational constant in equilibrium position (cm^-1)
α_e	rotational constant – first term (cm^-1)
γ_e	rotation-vibration interaction constant (cm^-1)
D_e	centrifugal distortion constant (cm^-1)
β_e	rotational constant – first term, centrifugal force (cm^-1)
r_e	internuclear distance (Å)
Trans.	observed transition(s) corresponding to electronic state
ν₀₀	position of 0-0 band (units noted in table)

Diatomic constants for ⁽⁵⁶⁾Fe¹⁶O
State	T_e	ω_e	ω_ex_e	ω_ey_e	B_e	α_e	γ_e	D_e	β_e	r_e	Trans.	ν₀₀
										R	41480 H
↳missing citation; Bass, Kuebler, et al., 1964; missing citation
c	26441	[545] H									c → A 1 R	22326 H
c	↳Rosen, 1945; Malet and Rosen, 1945; West and Broida, 1975
c'	23569	[535] H 2									c' → A 1 R	19449 H
c'	↳West and Broida, 1975
b	21962	[667] H			[0.471₇] 3					[1.695]	b 4 ↔ A 1 R	17908 H
	↳Rosen, 1945; missing citation; missing citation; Callear and Norrish, 1960; Bass, Kuebler, et al., 1964; Barrow and Senior, 1969; West and Broida, 1975
	(21865)	[(661)] H									b 4 ↔ A 4 1 R	17808 H
	↳Rosen, 1945; missing citation; missing citation; Callear and Norrish, 1960; Bass, Kuebler, et al., 1964; Barrow and Senior, 1969; West and Broida, 1975
State	T_e	ω_e	ω_ex_e	ω_ey_e	B_e	α_e	γ_e	D_e	β_e	r_e	Trans.	ν₀₀
a	21245	820 H	1		[0.497] 5					[1.65₁]	a 6 ↔ A 1 R	17267 H
a	↳Rosen, 1945; missing citation; missing citation; Callear and Norrish, 1960; Bass, Kuebler, et al., 1964; West and Broida, 1975
B (⁵Π)	14404	650 7 H	5 8								B → A 1 R	10340 H
	↳Bass and Benedict, 1952; West and Broida, 1975
											B → X R	14245 H
	↳Malet and Rosen, 1945; Bass and Benedict, 1952; West and Broida, 1975
A ⁵Σ⁺	3948 9	880.53 3 Z	4.63		0.5127₁ 3	0.0037₆		[6.₆E-7]		1.6259		3905 10
A ⁵Σ⁺	↳Malet and Rosen, 1945; West and Broida, 1975; Engelking and Lineberger, 1977
State	T_e	ω_e	ω_ex_e	ω_ey_e	B_e	α_e	γ_e	D_e	β_e	r_e	Trans.	ν₀₀
X ⁵Δ	0 9	965 7								(1.57) 11	12

Notes

The similarity of the vibrational constants suggests a common lower state for the five systems. Uncertain.

Fragments of an emission system, 18500 - 20000 cm^-1.

From the rotational analysis Barrow and Senior, 1969 of four bands of the short-wavelength component of b-A. They appear to be the Ω'= Ω" = 0 subbands of a quintet or septet Σ-Σ transition. An earlier analysis by Dhumwad and Narasimham, 1967 is incorrect.

Lifetime τ ~ 500 ns West and Broida, 1975.

Rotational analysis using tunable-laser excited fluorescence spectroscopy West and Broida, 1975.

Lifetime τ ~ 450 ns West and Broida, 1975.

From a re-analysis of B → X by Engelking and Lineberger, 1977. The FeO^- photoelectron spectrum Engelking and Lineberger, 1977 gives a ground state frequency of 970 ± 60 cm^-1

Large number of emission bands, 7100 - 15000 cm^-1; tentative vibrational analysis.

Symmetries assigned Engelking and Lineberger, 1977 on the basis of ab initio calculations Bagus and Preston, 1973.

From 0-0 band assignments for B → X Engelking and Lineberger, 1977 and B → A Bass and Benedict, 1952, West and Broida, 1975. From the FeO^- photoelectron spectrum Engelking and Lineberger, 1977 obtain 3990 ± 100 cm^-1.

Estimated Engelking and Lineberger, 1977 from relative vibrational intensities in the photoelectron spectrum of FeO^-.

The IR transition strength measured at 880 cm^-1 von Rosenberg and Wray, 1972, Fissan and Sulzmann, 1972 requires reinterpretation in view of the recent reassignment of the low-lying states Engelking and Lineberger, 1977.

Thermochemica1 value (mass-spectrom.) Cheetam and Barrow, 1967, Balducci, DeMaria, et al., 1971, Hildenbrand, 1975. See also Brewer and Mastick, 1951, Lagerqvist and Huldt, 1953.

Electron impact appearance potential Hildenbrand, 1975.

From D₀⁰(FeO) and the electron affinities of FeO and O.

From the laser photoelectron spectrum of FeO^- Engelking and Lineberger, 1977.

References

Go To: Top, Gas phase thermochemistry data, Gas phase ion energetics data, Constants of diatomic molecules, Notes

Chase, 1998
Chase, M.W., Jr., NIST-JANAF Themochemical Tables, Fourth Edition, J. Phys. Chem. Ref. Data, Monograph 9, 1998, 1-1951. [all data]

Hunter and Lias, 1998
Hunter, E.P.; Lias, S.G., Evaluated Gas Phase Basicities and Proton Affinities of Molecules: An Update, J. Phys. Chem. Ref. Data, 1998, 27, 3, 413-656, https://doi.org/10.1063/1.556018 . [all data]

Drechsler, Boesl, et al., 1997
Drechsler, G.; Boesl, U.; Bassmann, C.; Schlag, E.W., Mass selected anion-zero kinetic energy photoelectron spectroscopy (anion-ZEKE): Ground and low excited states of FeO, J. Chem. Phys., 1997, 107, 7, 2284-2291, https://doi.org/10.1063/1.474622 . [all data]

Engelking and Lineberger, 1977
Engelking, P.C.; Lineberger, W.C., Laser photoelecton spectrometry of FeO-: Electron affinity, electronic state separations, and ground state vibrations of iron oxide, and a new ground state assignment, J. Chem. Phys., 1977, 66, 5054. [all data]

Wu, Desai, et al., 1996
Wu, H.; Desai, R.; Wang, L.-S., Observation and Photoelectron Spectroscopic Study of Novel Mono- and Di-iron Oxide Molecules: FeOy- (y=1-4) and Fe2Oy- (y=1-5), J. Am. Chem. Soc., 1996, 118, 22, 5296, https://doi.org/10.1021/ja954153b . [all data]

Anderson, Lykke, et al., 1987
Anderson, T.; Lykke, K.R.; Neumark, D.M.; Lineberger, W.C., Autodetachment Study of the Electronic Spectroscopy of FeO^-, J. Chem. Phys., 1987, 86, 4, 1858, https://doi.org/10.1063/1.452137 . [all data]

Armentrout, Halle, et al., 1982
Armentrout, P.B.; Halle, L.F.; Beauchamp, J.L., Reaction of Cr⁺, Mn⁺, Fe⁺, Co⁺, and Ni⁺ with O₂ and N₂O. Examination of the translational energy dependence of the cross sections of endothermic reactions, J. Chem. Phys., 1982, 76, 2449. [all data]

Hildenbrand, 1975
Hildenbrand, D.L., Thermochemistry of molecular FeO, FeO⁺ and FeO₂, Chem. Phys. Lett., 1975, 34, 352. [all data]

Balducci, DeMaria, et al., 1971
Balducci, G.; DeMaria, G.; Guido, M.; Piacente, V., Dissociation energy of FeO, J. Chem. Phys., 1971, 55, 2596. [all data]

Bass, Kuebler, et al., 1964
Bass, A.M.; Kuebler, N.A.; Nelson, L.S., Observation of FeO in absorption by flash heating and kinetic spectroscopy, J. Chem. Phys., 1964, 40, 3121. [all data]

Rosen, 1945
Rosen, B., Spectra of diatomic oxides by the method of exploded wire, Nature (London), 1945, 156, 570. [all data]

Malet and Rosen, 1945
Malet, L.; Rosen, B., Contribution a l'etude du spectre de FeO, Bull. Soc. R. Sci. Liege, 1945, 14, 377. [all data]

West and Broida, 1975
West, J.B.; Broida, H.P., Chemiluminescence and photoluminescence of diatomic iron oxide, J. Chem. Phys., 1975, 62, 2566. [all data]

Callear and Norrish, 1960
Callear, A.B.; Norrish, R.G.W., The behaviour of additives in explosions and the mechanism of antiknock, Proc. R. Soc. London A, 1960, 259, 304-324. [all data]

Barrow and Senior, 1969
Barrow, R.F.; Senior, M., Ground state of gaeous FeO, Nature (London), 1969, 223, 1359. [all data]

Bass and Benedict, 1952
Bass, A.M.; Benedict, W.S., A new infrared band system of FeO, Astrophys. J., 1952, 116, 652. [all data]

Dhumwad and Narasimham, 1967
Dhumwad, R.K.; Narasimham, N.A., Rotational analysis of some of the bands of the orange system of FeO, Proc. Indian Acad. Sci. Sect. A, 1967, 64, 283. [all data]

Bagus and Preston, 1973
Bagus, P.S.; Preston, H.J.T., Lowest ⁵Σ⁺ state of FeO: an ab initio investigation, J. Chem. Phys., 1973, 59, 2986. [all data]

von Rosenberg and Wray, 1972
von Rosenberg, C.W., Jr.; Wray, K.L., Shock tube studies on Fe(CO)₅+O₂: 11μ FeO emission and kinetics, J. Quant. Spectrosc. Radiat. Transfer, 1972, 12, 531. [all data]

Fissan and Sulzmann, 1972
Fissan, H.; Sulzmann, K.G.P., Absorption coefficients for the infrared vibration-rotation spectrum of FeO, J. Quant. Spectrosc. Radiat. Transfer, 1972, 12, 979. [all data]

Cheetam and Barrow, 1967
Cheetam, C.J.; Barrow, R.F., Adv. High Temp. Chem., 1967, 1, 7. [all data]

Brewer and Mastick, 1951
Brewer, L.; Mastick, D.F., The stability of gaseous diatomic oxides, J. Chem. Phys., 1951, 19, 834. [all data]

Lagerqvist and Huldt, 1953
Lagerqvist, A.; Huldt, L., Die Dissoziationsenergien der gasformigen Oxyde CrO und FeO, Z. Naturforsch. A, 1953, 8, 493. [all data]

Notes

Go To: Top, Gas phase thermochemistry data, Gas phase ion energetics data, Constants of diatomic molecules, References

Symbols used in this document:

EA Electron affinity

S°_{gas,1 bar} Entropy of gas at standard conditions (1 bar)

Δ_fH°_gas Enthalpy of formation of gas at standard conditions
Data from NIST Standard Reference Database 69: NIST Chemistry WebBook
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EA	Electron affinity
S°_{gas,1 bar}	Entropy of gas at standard conditions (1 bar)
Δ_fH°_gas	Enthalpy of formation of gas at standard conditions