iron

Formula: Fe
Molecular weight: 55.845
IUPAC Standard InChI: InChI=1S/Fe
IUPAC Standard InChIKey: XEEYBQQBJWHFJM-UHFFFAOYSA-N
CAS Registry Number: 7439-89-6
Chemical structure:
This structure is also available as a 2d Mol file
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Information on this page:
Other data available:
- Reaction thermochemistry data
- Gas phase ion energetics data
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Gas phase thermochemistry data

Go To: Top, Condensed phase thermochemistry data, Ion clustering data, References, Notes

Quantity	Value	Units	Method	Reference	Comment
Δ_fH°_gas	99.300	kcal/mol	Review	Chase, 1998	Data last reviewed in March, 1978
Quantity	Value	Units	Method	Reference	Comment
S°_{gas,1 bar}	43.138	cal/mol*K	Review	Chase, 1998	Data last reviewed in March, 1978

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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Temperature (K)	3133.345 to 6000.
A	2.698980
B	1.670581
C	-0.265369
D	0.029243
E	1.359771
F	101.2280
G	49.32101
H	99.30010
Reference	Chase, 1998
Comment	Data last reviewed in March, 1978

Condensed phase thermochemistry data

Go To: Top, Gas phase thermochemistry data, Ion clustering data, References, Notes

Quantity	Value	Units	Method	Reference	Comment
Δ_fH°_liquid	2.964	kcal/mol	Review	Chase, 1998	Data last reviewed in March, 1978
Quantity	Value	Units	Method	Reference	Comment
S°_{liquid,1 bar}	8.308	cal/mol*K	Review	Chase, 1998	Data last reviewed in March, 1978

Liquid Phase Heat Capacity (Shomate Equation)

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Temperature (K)	1809. to 3133.345
A	11.00000
B	-4.504460×10^-9
C	1.456680×10^-9
D	-1.587071×10^-10
E	-1.970870×10^-9
F	-2.582560
G	17.33770
H	2.962481
Reference	Chase, 1998
Comment	Data last reviewed in March, 1978

Solid Phase Heat Capacity (Shomate Equation)

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Temperature (K)	298. to 700.	700. to 1042.	1042. to 1100.	1100. to 1809.	298. to 1809.
A	4.404561	-13806.80	-77.88860	-185.6450	5.730041
B	5.889821	32963.60	6.914140	219.7420	1.999941
C	-2.130430	-29343.50	0.000000	-91.71090	0.000066
D	2.309920	9245.320	0.000000	13.64280	-0.000021
E	-0.003022	954.3690	98.46150	57.87211	-0.000001
F	-1.570990	5754.940	178.2560	166.7360	0.064060
G	10.16130	-20880.50	57.80990	-133.4530	14.83350
H	0.000000	0.000000	0.000000	0.000000	1.861381
Reference	Chase, 1998	Chase, 1998	Chase, 1998	Chase, 1998	Chase, 1998
Comment	α-δ phase; Data last reviewed in March, 1978	α-δ phase; Data last reviewed in March, 1978	α-δ phase; Data last reviewed in March, 1978	α-δ phase; Data last reviewed in March, 1978	γ phase; Data last reviewed in March, 1978

Ion clustering data

Go To: Top, Gas phase thermochemistry data, Condensed phase thermochemistry data, References, Notes

Data compiled as indicated in comments:
M - Michael M. Meot-Ner (Mautner) and Sharon G. Lias
B - John E. Bartmess

Note: Please consider using the reaction search for this species. This page allows searching of all reactions involving this species. Searches may be limited to ion clustering reactions. A general reaction search form is also available.

Clustering reactions

+ iron = ( • iron )

By formula: Fe⁺ + Fe = (Fe⁺ • Fe)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	62.	kcal/mol	CID	Loh, Lian, et al., 1988	gas phase; M
Δ_rH°	62.4	kcal/mol	PDiss	Tecklenberg, Bricker, et al., 1988	gas phase; Δ_rH>; M

Enthalpy of reaction

Δ_rH° (kcal/mol)	T (K)	Method	Reference	Comment
64.1		CID	Armentrout and Kickel, 1994	gas phase; guided ion beam CID; M

( • iron ) + iron = ( • 2 iron )

By formula: (Fe⁺ • Fe) + Fe = (Fe⁺ • 2Fe)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	55.6	kcal/mol	PDiss	Tecklenberg, Bricker, et al., 1988	gas phase; Δ_rH<; M

Enthalpy of reaction

Δ_rH° (kcal/mol)	T (K)	Method	Reference	Comment
40.4		CID	Armentrout and Kickel, 1994	gas phase; guided ion beam CID; M

( • 2 iron ) + iron = ( • 3 iron )

By formula: (Fe⁺ • 2Fe) + Fe = (Fe⁺ • 3Fe)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	41.5	kcal/mol	CID	Loh, Lian, et al., 1988	gas phase; M

Enthalpy of reaction

Δ_rH° (kcal/mol)	T (K)	Method	Reference	Comment
51.6		CID	Armentrout and Kickel, 1994	gas phase; guided ion beam CID; M

( • 3 iron ) + iron = ( • 4 iron )

By formula: (Fe⁺ • 3Fe) + Fe = (Fe⁺ • 4Fe)

Enthalpy of reaction

Δ_rH° (kcal/mol)	T (K)	Method	Reference	Comment
62.1		CID	Armentrout and Kickel, 1994	gas phase; guided ion beam CID; M

( • 4 iron ) + iron = ( • 5 iron )

By formula: (Fe⁺ • 4Fe) + Fe = (Fe⁺ • 5Fe)

Enthalpy of reaction

Δ_rH° (kcal/mol)	T (K)	Method	Reference	Comment
75.3		CID	Armentrout and Kickel, 1994	gas phase; guided ion beam CID; M

( • 5 iron ) + iron = ( • 6 iron )

By formula: (Fe⁺ • 5Fe) + Fe = (Fe⁺ • 6Fe)

Enthalpy of reaction

Δ_rH° (kcal/mol)	T (K)	Method	Reference	Comment
76.5		CID	Armentrout and Kickel, 1994	gas phase; guided ion beam CID; M

( • 6 iron ) + iron = ( • 7 iron )

By formula: (Fe⁺ • 6Fe) + Fe = (Fe⁺ • 7Fe)

Enthalpy of reaction

Δ_rH° (kcal/mol)	T (K)	Method	Reference	Comment
60.2		CID	Armentrout and Kickel, 1994	gas phase; guided ion beam CID; M

( • 7 iron ) + iron = ( • 8 iron )

By formula: (Fe⁺ • 7Fe) + Fe = (Fe⁺ • 8Fe)

Enthalpy of reaction

Δ_rH° (kcal/mol)	T (K)	Method	Reference	Comment
67.2		CID	Armentrout and Kickel, 1994	gas phase; guided ion beam CID; M

( • 8 iron ) + iron = ( • 9 iron )

By formula: (Fe⁺ • 8Fe) + Fe = (Fe⁺ • 9Fe)

Enthalpy of reaction

Δ_rH° (kcal/mol)	T (K)	Method	Reference	Comment
67.9		CID	Armentrout and Kickel, 1994	gas phase; guided ion beam CID; M

( • 9 iron ) + iron = ( • 10 iron )

By formula: (Fe⁺ • 9Fe) + Fe = (Fe⁺ • 10Fe)

Enthalpy of reaction

Δ_rH° (kcal/mol)	T (K)	Method	Reference	Comment
73.6		CID	Armentrout and Kickel, 1994	gas phase; guided ion beam CID; M

( • 10 iron ) + iron = ( • 11 iron )

By formula: (Fe⁺ • 10Fe) + Fe = (Fe⁺ • 11Fe)

Enthalpy of reaction

Δ_rH° (kcal/mol)	T (K)	Method	Reference	Comment
79.8		CID	Armentrout and Kickel, 1994	gas phase; guided ion beam CID; M

( • 11 iron ) + iron = ( • 12 iron )

By formula: (Fe⁺ • 11Fe) + Fe = (Fe⁺ • 12Fe)

Enthalpy of reaction

Δ_rH° (kcal/mol)	T (K)	Method	Reference	Comment
97.5		CID	Armentrout and Kickel, 1994	gas phase; guided ion beam CID; M

( • 12 iron ) + iron = ( • 13 iron )

By formula: (Fe⁺ • 12Fe) + Fe = (Fe⁺ • 13Fe)

Enthalpy of reaction

Δ_rH° (kcal/mol)	T (K)	Method	Reference	Comment
67.2		CID	Armentrout and Kickel, 1994	gas phase; guided ion beam CID; M

( • 13 iron ) + iron = ( • 14 iron )

By formula: (Fe⁺ • 13Fe) + Fe = (Fe⁺ • 14Fe)

Enthalpy of reaction

Δ_rH° (kcal/mol)	T (K)	Method	Reference	Comment
90.1		CID	Armentrout and Kickel, 1994	gas phase; guided ion beam CID; M

( • 14 iron ) + iron = ( • 15 iron )

By formula: (Fe⁺ • 14Fe) + Fe = (Fe⁺ • 15Fe)

Enthalpy of reaction

Δ_rH° (kcal/mol)	T (K)	Method	Reference	Comment
76.2		CID	Armentrout and Kickel, 1994	gas phase; guided ion beam CID; M

( • 15 iron ) + iron = ( • 16 iron )

By formula: (Fe⁺ • 15Fe) + Fe = (Fe⁺ • 16Fe)

Enthalpy of reaction

Δ_rH° (kcal/mol)	T (K)	Method	Reference	Comment
77.2		CID	Armentrout and Kickel, 1994	gas phase; guided ion beam CID; M

( • 16 iron ) + iron = ( • 17 iron )

By formula: (Fe⁺ • 16Fe) + Fe = (Fe⁺ • 17Fe)

Enthalpy of reaction

Δ_rH° (kcal/mol)	T (K)	Method	Reference	Comment
74.3		CID	Armentrout and Kickel, 1994	gas phase; guided ion beam CID; M

( • 17 iron ) + iron = ( • 18 iron )

By formula: (Fe⁺ • 17Fe) + Fe = (Fe⁺ • 18Fe)

Enthalpy of reaction

Δ_rH° (kcal/mol)	T (K)	Method	Reference	Comment
89.1		CID	Armentrout and Kickel, 1994	gas phase; guided ion beam CID; M

(FeO^- • 4294967295 iron ) + iron = FeO^-

By formula: (FeO^- • 4294967295Fe) + Fe = FeO^-

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	94.3 ± 4.0	kcal/mol	N/A	Drechsler, Boesl, et al., 1997	gas phase; B
Δ_rH°	94.3 ± 7.0	kcal/mol	Ther	Engelking and Lineberger, 1977	gas phase; B

References

Go To: Top, Gas phase thermochemistry data, Condensed phase thermochemistry data, Ion clustering data, 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]

Loh, Lian, et al., 1988
Loh, S.K.; Lian, L.; Hales, D.A.; Armentrout, P.B., Collision - Induced Dissociation Processes of Nb4+ and Fe4+: Fission vs Evaporation, J. Chem. Phys., 1988, 89, 1, 610, https://doi.org/10.1063/1.455455 . [all data]

Tecklenberg, Bricker, et al., 1988
Tecklenberg, R.E.; Bricker, D.L.; Russel, D.H., Laser - Ion Beam Photodissociation Studies of Ionic Cluster Fragments of Iron Carbonyls: Fe(x)(CO)y+ (x = 1 - 3; y = 0 - 6), Organometallics, 1988, 7, 12, 2506, https://doi.org/10.1021/om00102a013 . [all data]

Armentrout and Kickel, 1994
Armentrout, P.B.; Kickel, B.L., Gas Phase Thermochemistry of Transition Metal Ligand Systems: Reassessment of Values and Periodic Trends, in Organometallic Ion Chemistry, B. S. Freiser, ed, 1994. [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]

Notes

Go To: Top, Gas phase thermochemistry data, Condensed phase thermochemistry data, Ion clustering data, References

Symbols used in this document:

S°_{gas,1 bar}	Entropy of gas at standard conditions (1 bar)
S°_{liquid,1 bar}	Entropy of liquid at standard conditions (1 bar)
T	Temperature
Δ_fH°_gas	Enthalpy of formation of gas at standard conditions
Δ_fH°_liquid	Enthalpy of formation of liquid at standard conditions
Δ_rH°	Enthalpy of reaction at standard conditions

Data from NIST Standard Reference Database 69: NIST Chemistry WebBook
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