potassium iodide

Gas phase thermochemistry data

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Quantity Value Units Method Reference Comment
ΔfH°gas-125.52kJ/molReviewChase, 1998Data last reviewed in June, 1967
Quantity Value Units Method Reference Comment
S°gas,1 bar258.28J/mol*KReviewChase, 1998Data last reviewed in June, 1967

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) 2500. - 6000.
A 37.40622
B 0.828440
C -0.002031
D 0.000174
E -0.047344
F -136.8683
G 303.0375
H -125.5200
ReferenceChase, 1998
Comment Data last reviewed in June, 1967

Condensed phase thermochemistry data

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Quantity Value Units Method Reference Comment
ΔfH°liquid-312.85kJ/molReviewChase, 1998Data last reviewed in June, 1967
Quantity Value Units Method Reference Comment
S°liquid,1 bar114.10J/mol*KReviewChase, 1998Data last reviewed in June, 1967
Quantity Value Units Method Reference Comment
ΔfH°solid-327.90kJ/molReviewChase, 1998Data last reviewed in June, 1967
Quantity Value Units Method Reference Comment
S°solid106.37J/mol*KReviewChase, 1998Data last reviewed in June, 1967

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) 954. - 2500.
A 72.38320
B -1.627693×10-9
C 1.020901×10-9
D -2.026337×10-10
E -4.120467×10-11
F -334.4271
G 201.6935
H -312.8465
ReferenceChase, 1998
Comment Data last reviewed in June, 1967

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. - 954.
A 73.62376
B -85.43644
C 130.0973
D -48.86619
E -0.502415
F -348.7987
G 212.7614
H -327.9005
ReferenceChase, 1998
Comment Data last reviewed in June, 1967

Phase change data

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Antoine Equation Parameters

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

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Temperature (K) A B C Reference Comment
1018. - 1597.4.402216421.797-136.338Stull, 1947Coefficents calculated by NIST from author's data.

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: John E. Bartmess

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

Iodide + potassium iodide = (Iodide • potassium iodide)

By formula: I- + IK = (I- • IK)

Quantity Value Units Method Reference Comment
ΔrH°163. ± 8.8kJ/molN/ABurdukovskaya, Kudin, et al., 1984gas phase; value altered from reference due to conversion from electron convention to ion convention

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

Electron affinity determinations

EA (eV) Method Reference Comment
0.728 ± 0.010LPESMiller, Leopold, et al., 1986B
0.50 ± 0.10LPESYang, Bloomfield, et al., 1992EA given is Vertical Detachment Energy. Adiabatic EA est as up to 1 eV smaller; B

Ionization energy determinations

IE (eV) Method Reference Comment
7.5 ± 0.4EIEmons, Horlbeck, et al., 1982LBLHLM
7.2 ± 0.1PEPotts and Price, 1977LLK
7.2 ± 0.1PEPotts, Williams, et al., 1974LLK
8.2 ± 0.3EIPlatel, 1965RDSH
7.4PEGoodman, Allen, et al., 1974Vertical value; LLK

Appearance energy determinations

Ion AE (eV) Other Products MethodReferenceComment
I+14.6 ± 0.3KEIPlatel, 1965RDSH
K+8.6 ± 0.3IEIPlatel, 1965RDSH
K+25.14 ± 0.04I(-)PEPotts and Price, 1977Vertical value; LLK

Ion clustering 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: 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

Iodide + potassium iodide = (Iodide • potassium iodide)

By formula: I- + IK = (I- • IK)

Quantity Value Units Method Reference Comment
ΔrH°163. ± 8.8kJ/molN/ABurdukovskaya, Kudin, et al., 1984gas phase; value altered from reference due to conversion from electron convention to ion convention

Constants of diatomic molecules

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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: Klaus P. Huber and Gerhard H. Herzberg

Data collected through January, 1977

Symbols used in the table of constants
SymbolMeaning
State electronic state and / or symmetry symbol
Te minimum electronic energy (cm-1)
ωe vibrational constant – first term (cm-1)
ωexe vibrational constant – second term (cm-1)
ωeye vibrational constant – third term (cm-1)
Be rotational constant in equilibrium position (cm-1)
αe rotational constant – first term (cm-1)
γe rotation-vibration interaction constant (cm-1)
De centrifugal distortion constant (cm-1)
βe rotational constant – first term, centrifugal force (cm-1)
re internuclear distance (Å)
Trans. observed transition(s) corresponding to electronic state
ν00 position of 0-0 band (units noted in table)
Diatomic constants for 39K127I
StateTeωeωexeωeyeBeαeγeDeβereTrans.ν00
Features in the elctron energy loss spectrum Geiger and Pfeiffer, 1968, Rudge, Trajmar, et al., 1976 at ~3.8, 4.7, 5.1 eV correspond to maxima in the absorption spectrum. Peaks at higher energies could indicate that KI absorbs strongly in the VUV region; structure above 19 eV may arise from excitation of a metal 3p electron.
Continuous absorption 1 above 26500 cm-1, maxima at 30800, 38400, 41700 2 cm-1.
↳Muller, 1927; Levi, 1934; Davidovits and Brodhead, 1967
A (0+) (26620) 3           
X 1Σ+ 0 186.53 4 0.574  0.06087473 0.00026776 3.88E-7 2.5934E-8 4E-12 3.047844 5  
↳Honig, Mandel, et al., 1954; Rusk and Gordy, 1962

Notes

1Absorption cross sections Davidovits and Brodhead, 1967. A preliminary measurement of the photodissociation product anisotropy by photofragment spectroscopy at 28800 cm-1 Ormerod, Powers, et al., 1974 indicates strong contributions from perpendicular transitions.
2Photodissociation produces K(4p 2P); similarly, photodissociation at 52600 cm-1 leads to K(5p 2P) Earl and Herm, 1974.
3This is one of five very shallow states (0+, 0-, 1, 1, 2) 8 arising from normal products K (2S1/2) + I (2P3/2). The analysis of K-off-I differential elastic scattering measurements Kaufmann, Lawter, et al., 1974 suggests that only 0+ (De ~ 150 cm-1, re ~ 3.85 Å) is favorably situated for transitions from the ground state. Acordingly, Kaufmann, Kinsey, et al., 1974 have analyzed the fluctuation bands observed in absorption from 19600 to 27000 cm-1 Sommermeyer, 1929, Levi, 1934 and in chemiluminescence 9 from 16300 to 26200 cm-1 Levi, 1934, Kaufmann, Kinsey, et al., 1974, Oldenborg, Gole, et al., 1974 in terms of the A ↔ X transition, assigning vibrational quanutm numbers v" from 2 to 64, and constructing an accurate potential curve for the excited state.
4missing note
5Rotation spectrum 11
6Thermochemical value Brewer and Brackett, 1961; flame photometry Bulewicz, Phillips, et al., 1961 gives 3.49 eV. Earlier spectroscopic estimates were 3.31 eV Levi, 1934 and ≤ 3.47 eV Barrow and Caunt, 1953.
7Adiabatic potential from the photoelectron spectrum Potts, Williams, et al., 1974, not corrected for thermal population of ground state vibrational levels; band maximum (vertical potential) at 7.68 eV.
8A differential scattering experiment investigating the collisional depolarization of polarized K atoms missing citation leads to the conclusion that J,J coupling would provide the most adequate description of these states.
9The actual onset and cutoff wavelengths depend on the experimental conditions: a beam-gas arrangement Oldenborg, Gole, et al., 1974 or flames Levi, 1934, Kaufmann, Kinsey, et al., 1974.
10From the microwave results by use of Dunham's theory.
11Quadrupole hyperfine structure Tiemann, Ali, et al., 1973. The dipole moment μel = 10.82 D Story and Hebert, 1976 was measured by the electric deflection method Story and Hebert, 1976; see also Rodebush, Murray, et al., 1936.
12From D00(KI) + I.P.(K) - I.P.(KI); Potts, Williams, et al., 1974, give 0.37 eV.
13From band maxima of the photoelectron spectrum Potts, Williams, et al., 1974, missing citation.

References

Go To: Top, Gas phase thermochemistry data, Condensed phase thermochemistry data, Phase change data, Reaction thermochemistry data, Gas phase ion energetics data, Ion clustering data, Constants of diatomic molecules, NIST Free Links, 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]

Stull, 1947
Stull, Daniel R., Vapor Pressure of Pure Substances. Organic and Inorganic Compounds, Ind. Eng. Chem., 1947, 39, 4, 517-540, https://doi.org/10.1021/ie50448a022 . [all data]

Burdukovskaya, Kudin, et al., 1984
Burdukovskaya, G.G.; Kudin, L.S.; Butman, M.F.; Krasnov, K.S., Ionic forms in the vapour over potassium iodide, Russ. J. Inorg. Chem., 1984, 29, 3020. [all data]

Miller, Leopold, et al., 1986
Miller, T.M.; Leopold, D.G.; Murray, K.K.; Lineberger, W.C., Electron Affinities of the Alkali Halides and the Structure of their Negative Ions, J. Chem. Phys., 1986, 85, 5, 2368, https://doi.org/10.1063/1.451091 . [all data]

Yang, Bloomfield, et al., 1992
Yang, Y.A.; Bloomfield, L.A.; Jin, C.; Wang, L.S.; Smalley, R.E., Ultraviolet Photoelectron Spectroscopy and Photofragmentation Studies of Excess Electrons in Potassium Iodide Cluster Anions, J. Chem. Phys., 1992, 96, 4, 2453, https://doi.org/10.1063/1.462049 . [all data]

Emons, Horlbeck, et al., 1982
Emons, H.-H.; Horlbeck, W.; Kiessling, D., Massenspektrometrische untersuchung der gasphase uber alkalimetalliodiden, Z. Anorg. Allg. Chem., 1982, 488, 212. [all data]

Potts and Price, 1977
Potts, A.W.; Price, W.C., Photoelectron studies of ionic materials using molecular beam techniques, Phys. Scr., 1977, 16, 191. [all data]

Potts, Williams, et al., 1974
Potts, A.W.; Williams, T.A.; Price, W.C., Photoelectron spectra and electronic structure of diatomic alkali halides, Proc. Roy. Soc. London A, 1974, 341, 147. [all data]

Platel, 1965
Platel, G., Mesures des potentials d'apparition des ions obtenus par impact electronique dans la phase vapeur des iodures alcalins et des melanges LiI-MI, J. Chim. Phys., 1965, 62, 1176. [all data]

Goodman, Allen, et al., 1974
Goodman, T.D.; Allen, J.D., Jr.; Cusachs, L.C.; Schweitzer, G.K., The photoelectron spectra of gaseous alkali halides, J. Electron Spectrosc. Relat. Phenom., 1974, 3, 289. [all data]

Geiger and Pfeiffer, 1968
Geiger, J.; Pfeiffer, H.-C., Untersuchung der Anregung innerer Elektronen von Alkalihalogenidmolekulen im Energieverlustspektrum von 25 keV-Elektronen, Z. Phys., 1968, 208, 105. [all data]

Rudge, Trajmar, et al., 1976
Rudge, M.R.H.; Trajmar, S.; Williams, W., Electron scattering by highly polar molecules. I. KI, Phys. Rev. A: Gen. Phys., 1976, 13, 2074. [all data]

Muller, 1927
Muller, L.A., 4. absorptionsspektren der alkalihalogenide in wasseriger losung und im dampf, Ann. Phys. (Leipzig), 1927, 82, 39. [all data]

Levi, 1934
Levi, Dissertation, Berlin, 1934, 0. [all data]

Davidovits and Brodhead, 1967
Davidovits, P.; Brodhead, D.C., Ultraviolet absorption cross sections for the alkali halide vapors, J. Chem. Phys., 1967, 46, 2968. [all data]

Honig, Mandel, et al., 1954
Honig, A.; Mandel, M.; Stitch, M.L.; Townes, C.H., Microwave spectra of the alkali halides, Phys. Rev., 1954, 96, 629. [all data]

Rusk and Gordy, 1962
Rusk, J.R.; Gordy, W., Millimeter wave molecular beam spectroscopy: alkali bromides and iodides, Phys. Rev., 1962, 127, 817. [all data]

Ormerod, Powers, et al., 1974
Ormerod, R.C.; Powers, T.R.; Rose, T.L., Molecular-beam photodissociation studies of alkali iodides, J. Chem. Phys., 1974, 60, 5109. [all data]

Earl and Herm, 1974
Earl, B.L.; Herm, R.R., Photodissociation of NaBr, Nal, and Kl vapors and collisional quenching of Na* (32P), K* (42P), and K* (52P) by foreign gases, J. Chem. Phys., 1974, 60, 4568. [all data]

Kaufmann, Lawter, et al., 1974
Kaufmann, K.J.; Lawter, J.R.; Kinsey, J.L., Differential elastic scattering of potassium atoms by atomic iodine at thermal energies, J. Chem. Phys., 1974, 60, 4016. [all data]

Kaufmann, Kinsey, et al., 1974
Kaufmann, K.J.; Kinsey, J.L.; Palmer, H.B.; Tewarson, A., Potassium iodide chemiluminescence in diffusion flames and the Kl upper-state potential, J. Chem. Phys., 1974, 60, 4023. [all data]

Sommermeyer, 1929
Sommermeyer, K., Ein neues spektrum der gasformigen alkalihalogenide und seine deutung, Z. Phys., 1929, 56, 548. [all data]

Oldenborg, Gole, et al., 1974
Oldenborg, R.C.; Gole, J.L.; Zare, R.N., Chemiluminescent spectra of alkali-halogen reactions, J. Chem. Phys., 1974, 60, 4032. [all data]

Brewer and Brackett, 1961
Brewer, L.; Brackett, E., The dissociation energies of gaseous alkali halides, Chem. Rev., 1961, 61, 425. [all data]

Bulewicz, Phillips, et al., 1961
Bulewicz, E.M.; Phillips, L.F.; Sugden, T.M., Determination of dissociation constants and heats of formation of simple molecules by flame photometry. Part 8. Stabilities of the gaseous diatomic halides of certain metals, Trans. Faraday Soc., 1961, 57, 921. [all data]

Barrow and Caunt, 1953
Barrow, R.F.; Caunt, A.D., The ultra-violet absorption spectra of some gaseous alkali-metal halides and the dissociation energy of fluorine, Proc. R. Soc. London A, 1953, 219, 120. [all data]

Tiemann, Ali, et al., 1973
Tiemann, E.; Ali, H.El.; Hoeft, J.; Torring, T., Hyperfeinstruktur von KJ, Z. Naturforsch. A, 1973, 28, 1058. [all data]

Story and Hebert, 1976
Story, T.L., Jr.; Hebert, A.J., Dipole moments of KI, RbBr, RbI, CsBr, and CsI by the electric deflection method, J. Chem. Phys., 1976, 64, 855. [all data]

Rodebush, Murray, et al., 1936
Rodebush, W.H.; Murray, L.A., Jr.; Bixler, M.E., The dipole moments of the alkali halides, J. Chem. Phys., 1936, 4, 372. [all data]

Notes

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