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
  • Condensed phase thermochemistry data
  • Phase change data
  • Reaction thermochemistry data
  • Gas phase ion energetics data
  • References
  • Notes
• Other data available:
  • 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

Go To: Top, Condensed phase thermochemistry data, Phase change data, Reaction 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.

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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Condensed 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.

Liquid 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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Solid 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

Go To: Top, Gas phase thermochemistry data, Condensed phase thermochemistry data, Phase change data, Reaction 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
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

Go To: Top, Gas phase thermochemistry data, Condensed phase thermochemistry data, Phase change data, Reaction 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.

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, Condensed 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)
  S°liquid,1 bar	Entropy of liquid at standard conditions (1 bar)
  S°solid	Entropy of solid at standard conditions
  S°solid,1 bar	Entropy of solid at standard conditions (1 bar)
  Tboil	Boiling point
  Ttriple	Triple point temperature
  ΔfH°gas	Enthalpy of formation of gas at standard conditions
  ΔfH°liquid	Enthalpy of formation of liquid at standard conditions
  ΔrH°	Enthalpy of reaction at standard conditions

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