potassium

• Formula: K
• Molecular weight: 39.0983
• IUPAC Standard InChI: InChI=1S/K Copy

  
• IUPAC Standard InChIKey: ZLMJMSJWJFRBEC-UHFFFAOYSA-N Copy
• CAS Registry Number: 7440-09-7
• 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.
• Information on this page:
  • Gas phase thermochemistry data
  • Phase change data
  • Reaction thermochemistry data
  • Gas phase ion energetics data
  • References
  • Notes
• Other data available:
  • Condensed phase thermochemistry data
  • Ion clustering data
• Data at other public NIST sites:
  • NIST Atomic Spectra Database - Lines Holdings (on physics web site)
  • 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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• NIST / TRC Web Thermo Tables, professional edition (thermophysical and thermochemical data)

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Gas phase thermochemistry data

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Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.

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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Phase change data

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Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.

Data compiled as indicated in comments:
TRC - Thermodynamics Research Center, NIST Boulder Laboratories, Chris Muzny director

Antoine Equation Parameters

log₁₀(P) = A − (B / (T + C))
    P = vapor pressure (atm)
    T = temperature (K)

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Reaction thermochemistry data

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Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.

Data compiled by: Michael M. Meot-Ner (Mautner) and Sharon G. Lias

Note: Please consider using the reaction search for this species. This page allows searching of all reactions involving this species. A general reaction search form is also available. Future versions of this site may rely on reaction search pages in place of the enumerated reaction displays seen below.

Individual Reactions

( • 10) +  = ( • 11)

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

( • 11) +  = ( • 12)

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

( • 12) +  = ( • 13)

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

( • 13) +  = ( • 14)

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

( • 14) +  = ( • 15)

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

( • 15) +  = ( • 16)

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

( • 16) +  = ( • 17)

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

( • 17) +  = ( • 18)

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

( • 18) +  = ( • 19)

By formula: (K⁺ • 18K) + K = (K⁺ • 19K)

( • 19) +  = ( • 20)

By formula: (K⁺ • 19K) + K = (K⁺ • 20K)

( • 20) +  = ( • 21)

By formula: (K⁺ • 20K) + K = (K⁺ • 21K)

( • 21) +  = ( • 22)

By formula: (K⁺ • 21K) + K = (K⁺ • 22K)

( • 22) +  = ( • 23)

By formula: (K⁺ • 22K) + K = (K⁺ • 23K)

( • 23) +  = ( • 24)

By formula: (K⁺ • 23K) + K = (K⁺ • 24K)

( • 9) +  = ( • 10)

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

( • 2) +  = ( • 3)

By formula: (K⁺ • 2K) + K = (K⁺ • 3K)

( • 3) +  = ( • 4)

By formula: (K⁺ • 3K) + K = (K⁺ • 4K)

( • 4) +  = ( • 5)

By formula: (K⁺ • 4K) + K = (K⁺ • 5K)

( • 5) +  = ( • 6)

By formula: (K⁺ • 5K) + K = (K⁺ • 6K)

( • 6) +  = ( • 7)

By formula: (K⁺ • 6K) + K = (K⁺ • 7K)

( • 7) +  = ( • 8)

By formula: (K⁺ • 7K) + K = (K⁺ • 8K)

( • 8) +  = ( • 9)

By formula: (K⁺ • 8K) + K = (K⁺ • 9K)

Gas phase ion energetics data

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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
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
RDSH - Henry M. Rosenstock, Keith Draxl, Bruce W. Steiner, and John T. Herron

View reactions leading to K⁺ (ion structure unspecified)

Ionization energy determinations

References

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Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.

Cox, Wagman, et al., 1984
Cox, J.D.; Wagman, D.D.; Medvedev, V.A., CODATA Key Values for Thermodynamics, Hemisphere Publishing Corp., New York, 1984, 1. [all data]

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

Honig and Kramer, 1969
Honig, R.E.; Kramer, D.A., Vapor pressure data for the solid and liquid elements, RCA Rev., 1969, 1969, 285. [all data]

Fiock and Rodebush, 1926
Fiock, E.F.; Rodebush, W.H., The Vapor Pressures and Thermal Properties of Potassium and Some Alkali Halides, J. Am. Chem. Soc., 1926, 48, 10, 2522-2528, https://doi.org/10.1021/ja01421a006 . [all data]

Brechignac, Cahuzac, et al., 1990
Brechignac, C.; Cahuzac, P.; Carlier, F.; De Frutos, M.; Leyniger, J., Cohesive Energies of (K)n+ 5<n<200 from Photoevaporation Experiments, J. Chem. Phys., 1990, 93, 10, 7449, https://doi.org/10.1063/1.459418 . [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]

Kelly, 1987
Kelly, R.L., Atomic and ionic spectrum lines of hydrogen through kryton, J. Phys. Chem. Ref. Data, 1987, 16. [all data]

Sugar and Corliss, 1985
Sugar, J.; Corliss, C., Atomic energy levels of the iron period elements: Potassium through nickel, J. Phys. Chem. Ref. Data, 1985, 14. [all data]

Farber, Srivastava, et al., 1982
Farber, M.; Srivastava, R.D.; Moyer, J.W., Mass spectrometric determination of the thermodynamics of potassium hydroxide and minor potassium-containing species required in magnetohydrodynamic power systems, J. Chem. Thermodyn., 1982, 14, 1103. [all data]

Zmbov, Wu, et al., 1977
Zmbov, K.F.; Wu, C.H.; Ihle, H.R., A mass spectrometric study of heteronuclear diatomic alkali metal molecules. Dissociation energies ionization potentials of NaLi, KLi, NaK, J. Chem. Phys., 1977, 67, 4603. [all data]

Simmons, Lowden, et al., 1977
Simmons, L.L.; Lowden, L.F.; Ehlert, T.C., A mass spectrometric study of K₂CO₃ and K₂O, J. Phys. Chem., 1977, 81, 706. [all data]

Williams and Potts, 1976
Williams, T.A.; Potts, A.W., Complexities in the HeI photoelectron spectra of alkali metal vapours, J. Electron Spectrosc. Relat. Phenom., 1976, 8, 331. [all data]

Moore, 1970
Moore, C.E., Ionization potentials and ionization limits derived from the analyses of optical spectra, Natl. Stand. Ref. Data Ser., (U.S. Natl. Bur. Stand.), 1970, 34, 1. [all data]

Notes

Go To: Top, Gas phase thermochemistry data, Phase change data, Reaction 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)
  Tboil	Boiling point
  Ttriple	Triple point temperature
  ΔfH°gas	Enthalpy of formation of gas at standard conditions
  ΔrH°	Enthalpy of reaction at standard conditions

• Data from NIST Standard Reference Database 69: NIST Chemistry WebBook
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