hafnium
- Formula: Hf
- Molecular weight: 178.49
- IUPAC Standard InChI: InChI=1S/Hf
- IUPAC Standard InChIKey: VBJZVLUMGGDVMO-UHFFFAOYSA-N
- CAS Registry Number: 7440-58-6
- Chemical structure:
This structure is also available as a 2d Mol file - Permanent link for this species. Use this link for bookmarking this species for future reference.
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- Data at other public NIST sites:
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- NIST Atomic Spectra Database - Levels Holdings (on physics web site)
- NIST Atomic Spectra Database - Ground states and ionization energies (on physics web site)
- Gas Phase Kinetics Database
- X-ray Photoelectron Spectroscopy Database, version 5.0
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Gas phase thermochemistry data
Go To: Top, Condensed phase thermochemistry data, Gas phase ion energetics data, References, Notes
Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.
| Quantity | Value | Units | Method | Reference | Comment |
|---|---|---|---|---|---|
| ΔfH°gas | 618.40 | kJ/mol | Review | Chase, 1998 | Data last reviewed in March, 1979 |
| Quantity | Value | Units | Method | Reference | Comment |
| S°gas,1 bar | 186.90 | J/mol*K | Review | Chase, 1998 | Data last reviewed in March, 1979 |
Gas Phase Heat Capacity (Shomate Equation)
Cp° = 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
Cp = heat capacity (J/mol*K)
H° = standard enthalpy (kJ/mol)
S° = standard entropy (J/mol*K)
t = temperature (K) / 1000.
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| Temperature (K) | 4963.793 to 6000. |
|---|---|
| A | 53.43135 |
| B | -14.43208 |
| C | 3.215568 |
| D | -0.181469 |
| E | -20.49164 |
| F | 567.3881 |
| G | 217.1521 |
| H | 618.3952 |
| Reference | Chase, 1998 |
| Comment | Data last reviewed in March, 1979 |
Condensed phase thermochemistry data
Go To: Top, Gas phase thermochemistry data, Gas phase ion energetics data, References, Notes
Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.
| Quantity | Value | Units | Method | Reference | Comment |
|---|---|---|---|---|---|
| ΔfH°liquid | 46.21 | kJ/mol | Review | Chase, 1998 | Data last reviewed in March, 1979 |
| Quantity | Value | Units | Method | Reference | Comment |
| S°liquid,1 bar | 71.94 | J/mol*K | Review | Chase, 1998 | Data last reviewed in March, 1979 |
Liquid Phase Heat Capacity (Shomate Equation)
Cp° = 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
Cp = heat capacity (J/mol*K)
H° = standard enthalpy (kJ/mol)
S° = standard entropy (J/mol*K)
t = temperature (K) / 1000.
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| Temperature (K) | 2500. to 4963.793 |
|---|---|
| A | 37.65604 |
| B | -1.195850×10-7 |
| C | 2.633457×10-8 |
| D | -1.977226×10-9 |
| E | -1.780309×10-7 |
| F | 15.45084 |
| G | 90.56477 |
| H | 46.20893 |
| Reference | Chase, 1998 |
| Comment | Data last reviewed in March, 1979 |
Solid Phase Heat Capacity (Shomate Equation)
Cp° = 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
Cp = heat capacity (J/mol*K)
H° = standard enthalpy (kJ/mol)
S° = standard entropy (J/mol*K)
t = temperature (K) / 1000.
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| Temperature (K) | 298. to 2500. | 298. to 2500. |
|---|---|---|
| A | 22.71033 | 14.99366 |
| B | 10.86443 | 9.234131 |
| C | -1.901809 | -0.000539 |
| D | 0.306368 | 0.000106 |
| E | -0.007587 | 0.000024 |
| F | -7.264303 | 13.82318 |
| G | 67.84356 | 76.50360 |
| H | 0.000000 | 18.68604 |
| Reference | Chase, 1998 | Chase, 1998 |
| Comment | α phase; Data last reviewed in March, 1979 | β phase; Data last reviewed in March, 1979 |
Gas phase ion energetics data
Go To: Top, Gas phase thermochemistry data, Condensed phase thermochemistry data, References, Notes
Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.
Data evaluated as indicated in comments:
L - Sharon G. Lias
Data compiled as indicated in comments:
LL - Sharon G. Lias and Joel F. Liebman
LLK - Sharon G. Lias, Rhoda D. Levin, and Sherif A. Kafafi
| Quantity | Value | Units | Method | Reference | Comment |
|---|---|---|---|---|---|
| IE (evaluated) | 6.82507 ± 0.00004 | eV | N/A | N/A | L |
Ionization energy determinations
| IE (eV) | Method | Reference | Comment |
|---|---|---|---|
| 6.82507 | EVAL | Lide, 1992 | LL |
| 6.82507 ± 0.00004 | LS | Callender, Hackett, et al., 1988 | LL |
| 6.65 ± 0.10 | EI | Rauh and Ackermann, 1979 | LLK |
| 6.7 ± 0.1 | EI | Rauh and Ackermann, 1974 | LLK |
References
Go To: Top, Gas phase thermochemistry data, Condensed phase thermochemistry data, Gas phase ion energetics data, Notes
Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.
Chase, 1998
Chase, M.W., Jr.,
NIST-JANAF Themochemical Tables, Fourth Edition,
J. Phys. Chem. Ref. Data, Monograph 9, 1998, 1-1951. [all data]
Lide, 1992
Lide, D.R. (Editor),
Ionization potentials of atoms and atomic ions
in Handbook of Chem. and Phys., 1992, 10-211. [all data]
Callender, Hackett, et al., 1988
Callender, C.L.; Hackett, P.A.; Rayner, D.M.,
First ionization potential of hafnium by double-resonance field-ionization spectroscopy,
J. Opt. Soc. Am. B, 1988, 5, 1341. [all data]
Rauh and Ackermann, 1979
Rauh, E.G.; Ackermann, R.J.,
The first ionization potentials of the transition metals,
J. Chem. Phys., 1979, 70, 1004. [all data]
Rauh and Ackermann, 1974
Rauh, E.G.; Ackermann, R.J.,
First ionization potentials of some refractory oxide vapors,
J. Chem. Phys., 1974, 60, 1396. [all data]
Notes
Go To: Top, Gas phase thermochemistry data, Condensed phase thermochemistry data, Gas phase ion energetics data, References
- Symbols used in this document:
IE (evaluated) Recommended ionization energy S°gas,1 bar Entropy of gas at standard conditions (1 bar) S°liquid,1 bar Entropy of liquid at standard conditions (1 bar) ΔfH°gas Enthalpy of formation of gas at standard conditions ΔfH°liquid Enthalpy of formation of liquid at standard conditions - Data from NIST Standard Reference Database 69: NIST Chemistry WebBook
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