Methylene, difluoro-
- Formula: CF2
- Molecular weight: 50.0075
- IUPAC Standard InChIKey: LTVOKYUPTHZZQH-UHFFFAOYSA-N
- CAS Registry Number: 2154-59-8
- Chemical structure:
This structure is also available as a 2d Mol file or as a computed 3d SD file
The 3d structure may be viewed using Java or Javascript. - Other names: Calcium difluoride; Difluoromethylene
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Gas phase thermochemistry data
Go To: Top, 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 compiled as indicated in comments:
ALS - Hussein Y. Afeefy, Joel F. Liebman, and Stephen E. Stein
Quantity | Value | Units | Method | Reference | Comment |
---|---|---|---|---|---|
ΔfH°gas | -43.499 | kcal/mol | Review | Chase, 1998 | Data last reviewed in June, 1970 |
ΔfH°gas | -41.1 ± 2.0 | kcal/mol | Eqk | Ehlert, 1969 | ALS |
Quantity | Value | Units | Method | Reference | Comment |
S°gas,1 bar | 57.560 | cal/mol*K | Review | Chase, 1998 | Data last reviewed in June, 1970 |
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 600. | 600. to 6000. |
---|---|---|
A | 2.109410 | 14.18440 |
B | 29.96300 | -0.553818 |
C | -30.94981 | 0.212839 |
D | 12.02940 | -0.013355 |
E | 0.062082 | -0.828763 |
F | -45.00280 | -50.09931 |
G | 52.79830 | 71.28511 |
H | -43.50000 | -43.50000 |
Reference | Chase, 1998 | Chase, 1998 |
Comment | Data last reviewed in June, 1970 | Data last reviewed in June, 1970 |
Reaction thermochemistry data
Go To: Top, Gas 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 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
By formula: (CF3- • 4294967295CF2) + CF2 = CF3-
Quantity | Value | Units | Method | Reference | Comment |
---|---|---|---|---|---|
ΔrH° | 49.8 ± 2.4 | kcal/mol | N/A | Deyerl, Alconcel, et al., 2001 | gas phase; Adiabatic EA, from vibrational structure of spectrum |
ΔrH° | 50.9 ± 2.9 | kcal/mol | N/A | Bartmess, Scott, et al., 1979 | gas phase; Paulino and Squires, 1991 suggests that this acidity may be too weak by ca. 5 kcal/mol. However, G2 calcn(JEB) give ΔHacid=379.9, ΔGacid=372.0; value altered from reference due to change in acidity scale |
ΔrH° | 55.9 ± 2.7 | kcal/mol | CIDT | Paulino and Squires, 1991 | gas phase; Neutral heat is based on a fluoroform acidity that may be too weak by up to 5 kcal/mol |
(CAS Reg. No. 53959-80-1 • 4294967295) + = CAS Reg. No. 53959-80-1
By formula: (CAS Reg. No. 53959-80-1 • 4294967295CF2) + CF2 = CAS Reg. No. 53959-80-1
Quantity | Value | Units | Method | Reference | Comment |
---|---|---|---|---|---|
ΔrH° | <8.00 | kcal/mol | CIDT | Paulino and Squires, 1991, 2 | gas phase; Probably CF2..Cl-, non-covalent. |
References
Go To: Top, Gas phase thermochemistry data, Reaction thermochemistry 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]
Ehlert, 1969
Ehlert, T.C.,
Bonding in C1 and C2 fluroides,
J. Phys. Chem., 1969, 73, 949-953. [all data]
Deyerl, Alconcel, et al., 2001
Deyerl, H.J.; Alconcel, L.S.; Continetti, R.E.,
Photodetachment imaging studies of the electron affinity of CF3,
J. Phys. Chem. A, 2001, 105, 3, 552-557, https://doi.org/10.1021/jp003137k
. [all data]
Bartmess, Scott, et al., 1979
Bartmess, J.E.; Scott, J.A.; McIver, R.T., Jr.,
The gas phase acidity scale from methanol to phenol,
J. Am. Chem. Soc., 1979, 101, 6047. [all data]
Paulino and Squires, 1991
Paulino, J.A.; Squires, R.R.,
Carbene Thermochemistry from Collision-Induced Dissociation Threshold Energy Measurements - The Heats of Formation of X1A1 CF2 and X1A1 CCl2,
J. Am. Chem. Soc., 1991, 113, 15, 5573, https://doi.org/10.1021/ja00015a009
. [all data]
Paulino and Squires, 1991, 2
Paulino, J.A.; Squires, R.R.,
Carbene Anion Complexes - Unusual Structural and Thermochemical Features of alpha-Halocarbanions in the Gas Phase,
J. Am. Chem. Soc., 1991, 113, 5, 1845, https://doi.org/10.1021/ja00005a067
. [all data]
Notes
Go To: Top, Gas phase thermochemistry data, Reaction thermochemistry data, References
- 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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