Boron dihydride
- Formula: BH2
- Molecular weight: 12.827
- CAS Registry Number: 14452-64-3
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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.
| Quantity | Value | Units | Method | Reference | Comment |
|---|---|---|---|---|---|
| ΔfH°gas | 48.000 | kcal/mol | Review | Chase, 1998 | Data last reviewed in December, 1964 |
| Quantity | Value | Units | Method | Reference | Comment |
| S°gas,1 bar | 43.066 | cal/mol*K | Review | Chase, 1998 | Data last reviewed in December, 1964 |
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 (cal/mol*K)
H° = standard enthalpy (kcal/mol)
S° = standard entropy (cal/mol*K)
t = temperature (K) / 1000.
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| Temperature (K) | 298. to 1300. | 1300. to 6000. |
|---|---|---|
| A | 6.684052 | 13.37650 |
| B | 6.976721 | 0.780297 |
| C | -1.531891 | -0.147469 |
| D | -0.157588 | 0.009687 |
| E | -0.043815 | -2.337410 |
| F | 45.56379 | 39.20079 |
| G | 48.89849 | 53.22610 |
| H | 48.00000 | 48.00000 |
| Reference | Chase, 1998 | Chase, 1998 |
| Comment | Data last reviewed in December, 1964 | Data last reviewed in December, 1964 |
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
HB- + = H2B
| Quantity | Value | Units | Method | Reference | Comment |
|---|---|---|---|---|---|
| ΔrH° | 389.3 ± 6.6 | kcal/mol | D-EA | Reid, 1993 | gas phase |
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:
B - John E. Bartmess
RDSH - Henry M. Rosenstock, Keith Draxl, Bruce W. Steiner, and John T. Herron
View reactions leading to H2B+ (ion structure unspecified)
Ionization energy determinations
| IE (eV) | Method | Reference | Comment |
|---|---|---|---|
| 9.8 ± 0.2 | EI | Fehlner and Koski, 1964 | RDSH |
De-protonation reactions
HB- + = H2B
| Quantity | Value | Units | Method | Reference | Comment |
|---|---|---|---|---|---|
| ΔrH° | 389.3 ± 6.6 | kcal/mol | D-EA | Reid, 1993 | gas phase; B |
Vibrational and/or electronic energy levels
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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: Marilyn E. Jacox
State: A
| Energy (cm-1) |
Med. | Transition | λmin (nm) |
λmax (nm) |
References | ||
|---|---|---|---|---|---|---|---|
| To = 4194.1 | gas | A-X | 640 | 870 | Herzberg and Johns, 1967 | ||
| Vib. sym. |
No. | Approximate type of mode |
cm-1 | Med. | Method | References | |
|---|---|---|---|---|---|---|---|
| a1 | 2 | Bend | 953.6 | gas | AB | Herzberg and Johns, 1967 | |
Additional references: Jacox, 1994, page 17
Notes
| o | Energy separation between the v = 0 levels of the excited and electronic ground states. |
References
Go To: Top, Gas phase thermochemistry data, Reaction thermochemistry data, Gas phase ion energetics data, Vibrational and/or electronic energy levels, 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]
Reid, 1993
Reid, C.J.,
Electron Affinities of BH, B2, BC, and BN molecules determined using Charge Inversion Spectrometry,
Int. J. Mass Spectrom. Ion Proc., 1993, 127, 147, https://doi.org/10.1016/0168-1176(93)87087-9
. [all data]
Fehlner and Koski, 1964
Fehlner, T.P.; Koski, W.S.,
Direct detection of the borane molecule and the boryl radical by mass spectrometry,
J. Am. Chem. Soc., 1964, 86, 2733. [all data]
Herzberg and Johns, 1967
Herzberg, G.; Johns, J.W.C.,
The Spectrum and Structure of the Free BHFormula Radical,
Proc. Roy. Soc. (London) A298, 1967, 298, 1453, 142, https://doi.org/10.1098/rspa.1967.0096
. [all data]
Jacox, 1994
Jacox, M.E.,
Vibrational and electronic energy levels of polyatomic transient molecules, American Chemical Society, Washington, DC, 1994, 464. [all data]
Notes
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- Symbols used in this document:
S°gas,1 bar Entropy of gas at standard conditions (1 bar) 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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