cyclopentadienide anion
- Formula: C5H5-
- Molecular weight: 65.0937
- IUPAC Standard InChI: InChI=1S/C5H5/c1-2-4-5-3-1/h1-5H/q-1
- IUPAC Standard InChIKey: SINKOGOPEQSHQD-UHFFFAOYSA-N
- CAS Registry Number: 12127-83-2
- 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. - Permanent link for this species. Use this link for bookmarking this species for future reference.
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Reaction thermochemistry data
Go To: Top, Gas phase ion energetics data, Ion clustering 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:
B - John E. Bartmess
M - 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
+
=
| Quantity | Value | Units | Method | Reference | Comment |
|---|---|---|---|---|---|
| ΔrH° | 353.9 ± 2.2 | kcal/mol | G+TS | Bartmess, Scott, et al., 1979 | gas phase; value altered from reference due to change in acidity scale; B |
| ΔrH° | 354.9 ± 2.9 | kcal/mol | G+TS | Cumming and Kebarle, 1978 | gas phase; B |
| ΔrH° | 357.2 ± 2.0 | kcal/mol | D-EA | Engelking and Lineberger, 1977 | gas phase; B |
| Quantity | Value | Units | Method | Reference | Comment |
| ΔrG° | 347.7 ± 2.0 | kcal/mol | IMRE | Bartmess, Scott, et al., 1979 | gas phase; value altered from reference due to change in acidity scale; B |
| ΔrG° | 348.7 ± 2.0 | kcal/mol | IMRE | Cumming and Kebarle, 1978 | gas phase; B |
+
= (
•
)
By formula: C5H5- + C5H6 = (C5H5- • C5H6)
| Quantity | Value | Units | Method | Reference | Comment |
|---|---|---|---|---|---|
| ΔrH° | <8.60 | kcal/mol | IMRB | Meot-ner, 1988 | gas phase; B,M |
| Quantity | Value | Units | Method | Reference | Comment |
| ΔrS° | 20. | cal/mol*K | N/A | Meot-ner, 1988 | gas phase; Entropy change calculated or estimated, DG<, ΔrH<; M |
| Quantity | Value | Units | Method | Reference | Comment |
| ΔrG° | <2.6 ± 1.0 | kcal/mol | IMRB | Meot-ner, 1988 | gas phase; B |
Free energy of reaction
| ΔrG° (kcal/mol) | T (K) | Method | Reference | Comment |
|---|---|---|---|---|
| 3.6 | 250. | PHPMS | Meot-ner, 1988 | gas phase; Entropy change calculated or estimated, DG<, ΔrH<; M |
( • 2C2D3N) + C2D3N = (
• 3C2D3N)
By formula: (C5H5- • 2C2D3N) + C2D3N = (C5H5- • 3C2D3N)
| Quantity | Value | Units | Method | Reference | Comment |
|---|---|---|---|---|---|
| ΔrH° | 10.2 | kcal/mol | PHPMS | Meot-ner, 1988 | gas phase; Entropy change calculated or estimated, ΔrH<, CD3CN; M |
| Quantity | Value | Units | Method | Reference | Comment |
| ΔrS° | 22. | cal/mol*K | N/A | Meot-ner, 1988 | gas phase; Entropy change calculated or estimated, ΔrH<, CD3CN; M |
Free energy of reaction
| ΔrG° (kcal/mol) | T (K) | Method | Reference | Comment |
|---|---|---|---|---|
| 5.1 | 232. | PHPMS | Meot-ner, 1988 | gas phase; Entropy change calculated or estimated, ΔrH<, CD3CN; M |
+
= (
•
)
By formula: C5H5- + H2O = (C5H5- • H2O)
| Quantity | Value | Units | Method | Reference | Comment |
|---|---|---|---|---|---|
| ΔrH° | 11.0 ± 1.0 | kcal/mol | TDAs | Meot-ner, 1988 | gas phase; B,M |
| Quantity | Value | Units | Method | Reference | Comment |
| ΔrS° | 16.1 | cal/mol*K | PHPMS | Meot-ner, 1988 | gas phase; M |
| Quantity | Value | Units | Method | Reference | Comment |
| ΔrG° | 6.2 ± 1.0 | kcal/mol | TDAs | Meot-ner, 1988 | gas phase; B |
+
= (
•
)
By formula: C5H5- + C7H8O = (C5H5- • C7H8O)
| Quantity | Value | Units | Method | Reference | Comment |
|---|---|---|---|---|---|
| ΔrH° | 19.2 ± 1.0 | kcal/mol | TDAs | Meot-ner, 1988 | gas phase; B,M |
| Quantity | Value | Units | Method | Reference | Comment |
| ΔrS° | 29.8 | cal/mol*K | PHPMS | Meot-ner, 1988 | gas phase; M |
| Quantity | Value | Units | Method | Reference | Comment |
| ΔrG° | 10.3 ± 1.0 | kcal/mol | TDAs | Meot-ner, 1988 | gas phase; B |
+
= (
•
)
By formula: C5H5- + C2H3F3O = (C5H5- • C2H3F3O)
| Quantity | Value | Units | Method | Reference | Comment |
|---|---|---|---|---|---|
| ΔrH° | 20.6 ± 1.0 | kcal/mol | TDAs | Meot-ner, 1988 | gas phase; B,M |
| Quantity | Value | Units | Method | Reference | Comment |
| ΔrS° | 24.3 | cal/mol*K | PHPMS | Meot-ner, 1988 | gas phase; M |
| Quantity | Value | Units | Method | Reference | Comment |
| ΔrG° | 13.3 ± 1.0 | kcal/mol | TDAs | Meot-ner, 1988 | gas phase; B |
+
= (
•
)
By formula: C5H5- + C3H6O = (C5H5- • C3H6O)
| Quantity | Value | Units | Method | Reference | Comment |
|---|---|---|---|---|---|
| ΔrH° | 13.5 ± 1.0 | kcal/mol | TDAs | Meot-ner, 1988 | gas phase; B,M |
| Quantity | Value | Units | Method | Reference | Comment |
| ΔrS° | 21.8 | cal/mol*K | PHPMS | Meot-ner, 1988 | gas phase; M |
| Quantity | Value | Units | Method | Reference | Comment |
| ΔrG° | 7.0 ± 1.0 | kcal/mol | TDAs | Meot-ner, 1988 | gas phase; B |
+
= (
•
)
By formula: C5H5- + C4H10O = (C5H5- • C4H10O)
| Quantity | Value | Units | Method | Reference | Comment |
|---|---|---|---|---|---|
| ΔrH° | 17.0 ± 1.0 | kcal/mol | TDAs | Meot-ner, 1988 | gas phase; B,M |
| Quantity | Value | Units | Method | Reference | Comment |
| ΔrS° | 32.0 | cal/mol*K | PHPMS | Meot-ner, 1988 | gas phase; M |
| Quantity | Value | Units | Method | Reference | Comment |
| ΔrG° | 7.4 ± 1.0 | kcal/mol | TDAs | Meot-ner, 1988 | gas phase; B |
( • C2D3N) + C2D3N = (
• 2C2D3N)
By formula: (C5H5- • C2D3N) + C2D3N = (C5H5- • 2C2D3N)
| Quantity | Value | Units | Method | Reference | Comment |
|---|---|---|---|---|---|
| ΔrH° | 13.1 | kcal/mol | PHPMS | Meot-ner, 1988 | gas phase; CD3CN; M |
| Quantity | Value | Units | Method | Reference | Comment |
| ΔrS° | 22.8 | cal/mol*K | PHPMS | Meot-ner, 1988 | gas phase; CD3CN; M |
+
= (
•
)
By formula: C5H5- + CH4O = (C5H5- • CH4O)
| Quantity | Value | Units | Method | Reference | Comment |
|---|---|---|---|---|---|
| ΔrH° | 13.2 ± 1.0 | kcal/mol | TDAs | Meot-ner, 1988 | gas phase; B |
| Quantity | Value | Units | Method | Reference | Comment |
| ΔrG° | 6.9 ± 1.0 | kcal/mol | TDAs | Meot-ner, 1988 | gas phase; B |
+
= (
•
)
By formula: C5H5- + C2H3N = (C5H5- • C2H3N)
| Quantity | Value | Units | Method | Reference | Comment |
|---|---|---|---|---|---|
| ΔrH° | 15.5 ± 1.0 | kcal/mol | TDAs | Meot-ner, 1988 | gas phase; B |
| Quantity | Value | Units | Method | Reference | Comment |
| ΔrG° | 8.7 ± 1.0 | kcal/mol | TDAs | Meot-ner, 1988 | gas phase; B |
( •
) +
= (
• 2
)
By formula: (C5H5- • H2O) + H2O = (C5H5- • 2H2O)
| Quantity | Value | Units | Method | Reference | Comment |
|---|---|---|---|---|---|
| ΔrH° | 10.0 | kcal/mol | PHPMS | Meot-ner, 1988 | gas phase; M |
| Quantity | Value | Units | Method | Reference | Comment |
| ΔrS° | 17.4 | cal/mol*K | PHPMS | Meot-ner, 1988 | gas phase; M |
( •
) +
= (
• 2
)
By formula: (C5H5- • C3H6O) + C3H6O = (C5H5- • 2C3H6O)
| Quantity | Value | Units | Method | Reference | Comment |
|---|---|---|---|---|---|
| ΔrH° | 9.8 | kcal/mol | PHPMS | Meot-ner, 1988 | gas phase; M |
| Quantity | Value | Units | Method | Reference | Comment |
| ΔrS° | 16.4 | cal/mol*K | PHPMS | Meot-ner, 1988 | gas phase; M |
By formula: C5H5- + C2D3N = (C5H5- • C2D3N)
| Quantity | Value | Units | Method | Reference | Comment |
|---|---|---|---|---|---|
| ΔrH° | 15.5 | kcal/mol | PHPMS | Meot-ner, 1988 | gas phase; M |
| Quantity | Value | Units | Method | Reference | Comment |
| ΔrS° | 22.8 | cal/mol*K | PHPMS | Meot-ner, 1988 | gas phase; M |
By formula: C5H5- + CCoO = C6H5CoO-
| Quantity | Value | Units | Method | Reference | Comment |
|---|---|---|---|---|---|
| ΔrH° | 10.20 ± 0.80 | kcal/mol | N/A | Sunderlin and Squires, 1999 | gas phase; B |
+
= C5H5Co-
By formula: C5H5- + Co = C5H5Co-
| Quantity | Value | Units | Method | Reference | Comment |
|---|---|---|---|---|---|
| ΔrH° | 7.00 ± 0.60 | kcal/mol | N/A | Sunderlin and Squires, 1999 | gas phase; B |
Gas phase ion energetics data
Go To: Top, Reaction thermochemistry data, Ion clustering 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
Protonation reactions
+
=
| Quantity | Value | Units | Method | Reference | Comment |
|---|---|---|---|---|---|
| ΔrH° | 353.9 ± 2.2 | kcal/mol | G+TS | Bartmess, Scott, et al., 1979 | gas phase; value altered from reference due to change in acidity scale |
| ΔrH° | 354.9 ± 2.9 | kcal/mol | G+TS | Cumming and Kebarle, 1978 | gas phase |
| ΔrH° | 357.2 ± 2.0 | kcal/mol | D-EA | Engelking and Lineberger, 1977 | gas phase |
| Quantity | Value | Units | Method | Reference | Comment |
| ΔrG° | 347.7 ± 2.0 | kcal/mol | IMRE | Bartmess, Scott, et al., 1979 | gas phase; value altered from reference due to change in acidity scale |
| ΔrG° | 348.7 ± 2.0 | kcal/mol | IMRE | Cumming and Kebarle, 1978 | gas phase |
Ion clustering data
Go To: Top, 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.
Data compiled as indicated in comments:
B - John E. Bartmess
M - 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. Searches may be limited to ion clustering reactions. A general reaction search form is also available.
Clustering reactions
By formula: C5H5- + CCoO = C6H5CoO-
| Quantity | Value | Units | Method | Reference | Comment |
|---|---|---|---|---|---|
| ΔrH° | 10.20 ± 0.80 | kcal/mol | N/A | Sunderlin and Squires, 1999 | gas phase; B |
+
= (
•
)
By formula: C5H5- + CH4O = (C5H5- • CH4O)
| Quantity | Value | Units | Method | Reference | Comment |
|---|---|---|---|---|---|
| ΔrH° | 13.2 ± 1.0 | kcal/mol | TDAs | Meot-ner, 1988 | gas phase; B |
| Quantity | Value | Units | Method | Reference | Comment |
| ΔrG° | 6.9 ± 1.0 | kcal/mol | TDAs | Meot-ner, 1988 | gas phase; B |
By formula: C5H5- + C2D3N = (C5H5- • C2D3N)
| Quantity | Value | Units | Method | Reference | Comment |
|---|---|---|---|---|---|
| ΔrH° | 15.5 | kcal/mol | PHPMS | Meot-ner, 1988 | gas phase; M |
| Quantity | Value | Units | Method | Reference | Comment |
| ΔrS° | 22.8 | cal/mol*K | PHPMS | Meot-ner, 1988 | gas phase; M |
( • C2D3N) + C2D3N = (
• 2C2D3N)
By formula: (C5H5- • C2D3N) + C2D3N = (C5H5- • 2C2D3N)
| Quantity | Value | Units | Method | Reference | Comment |
|---|---|---|---|---|---|
| ΔrH° | 13.1 | kcal/mol | PHPMS | Meot-ner, 1988 | gas phase; CD3CN; M |
| Quantity | Value | Units | Method | Reference | Comment |
| ΔrS° | 22.8 | cal/mol*K | PHPMS | Meot-ner, 1988 | gas phase; CD3CN; M |
( • 2C2D3N) + C2D3N = (
• 3C2D3N)
By formula: (C5H5- • 2C2D3N) + C2D3N = (C5H5- • 3C2D3N)
| Quantity | Value | Units | Method | Reference | Comment |
|---|---|---|---|---|---|
| ΔrH° | 10.2 | kcal/mol | PHPMS | Meot-ner, 1988 | gas phase; Entropy change calculated or estimated, ΔrH<, CD3CN; M |
| Quantity | Value | Units | Method | Reference | Comment |
| ΔrS° | 22. | cal/mol*K | N/A | Meot-ner, 1988 | gas phase; Entropy change calculated or estimated, ΔrH<, CD3CN; M |
Free energy of reaction
| ΔrG° (kcal/mol) | T (K) | Method | Reference | Comment |
|---|---|---|---|---|
| 5.1 | 232. | PHPMS | Meot-ner, 1988 | gas phase; Entropy change calculated or estimated, ΔrH<, CD3CN; M |
+
= (
•
)
By formula: C5H5- + C2H3F3O = (C5H5- • C2H3F3O)
| Quantity | Value | Units | Method | Reference | Comment |
|---|---|---|---|---|---|
| ΔrH° | 20.6 ± 1.0 | kcal/mol | TDAs | Meot-ner, 1988 | gas phase; B,M |
| Quantity | Value | Units | Method | Reference | Comment |
| ΔrS° | 24.3 | cal/mol*K | PHPMS | Meot-ner, 1988 | gas phase; M |
| Quantity | Value | Units | Method | Reference | Comment |
| ΔrG° | 13.3 ± 1.0 | kcal/mol | TDAs | Meot-ner, 1988 | gas phase; B |
+
= (
•
)
By formula: C5H5- + C2H3N = (C5H5- • C2H3N)
| Quantity | Value | Units | Method | Reference | Comment |
|---|---|---|---|---|---|
| ΔrH° | 15.5 ± 1.0 | kcal/mol | TDAs | Meot-ner, 1988 | gas phase; B |
| Quantity | Value | Units | Method | Reference | Comment |
| ΔrG° | 8.7 ± 1.0 | kcal/mol | TDAs | Meot-ner, 1988 | gas phase; B |
+
= (
•
)
By formula: C5H5- + C3H6O = (C5H5- • C3H6O)
| Quantity | Value | Units | Method | Reference | Comment |
|---|---|---|---|---|---|
| ΔrH° | 13.5 ± 1.0 | kcal/mol | TDAs | Meot-ner, 1988 | gas phase; B,M |
| Quantity | Value | Units | Method | Reference | Comment |
| ΔrS° | 21.8 | cal/mol*K | PHPMS | Meot-ner, 1988 | gas phase; M |
| Quantity | Value | Units | Method | Reference | Comment |
| ΔrG° | 7.0 ± 1.0 | kcal/mol | TDAs | Meot-ner, 1988 | gas phase; B |
( •
) +
= (
• 2
)
By formula: (C5H5- • C3H6O) + C3H6O = (C5H5- • 2C3H6O)
| Quantity | Value | Units | Method | Reference | Comment |
|---|---|---|---|---|---|
| ΔrH° | 9.8 | kcal/mol | PHPMS | Meot-ner, 1988 | gas phase; M |
| Quantity | Value | Units | Method | Reference | Comment |
| ΔrS° | 16.4 | cal/mol*K | PHPMS | Meot-ner, 1988 | gas phase; M |
+
= (
•
)
By formula: C5H5- + C4H10O = (C5H5- • C4H10O)
| Quantity | Value | Units | Method | Reference | Comment |
|---|---|---|---|---|---|
| ΔrH° | 17.0 ± 1.0 | kcal/mol | TDAs | Meot-ner, 1988 | gas phase; B,M |
| Quantity | Value | Units | Method | Reference | Comment |
| ΔrS° | 32.0 | cal/mol*K | PHPMS | Meot-ner, 1988 | gas phase; M |
| Quantity | Value | Units | Method | Reference | Comment |
| ΔrG° | 7.4 ± 1.0 | kcal/mol | TDAs | Meot-ner, 1988 | gas phase; B |
+
= (
•
)
By formula: C5H5- + C5H6 = (C5H5- • C5H6)
| Quantity | Value | Units | Method | Reference | Comment |
|---|---|---|---|---|---|
| ΔrH° | <8.60 | kcal/mol | IMRB | Meot-ner, 1988 | gas phase; B,M |
| Quantity | Value | Units | Method | Reference | Comment |
| ΔrS° | 20. | cal/mol*K | N/A | Meot-ner, 1988 | gas phase; Entropy change calculated or estimated, DG<, ΔrH<; M |
| Quantity | Value | Units | Method | Reference | Comment |
| ΔrG° | <2.6 ± 1.0 | kcal/mol | IMRB | Meot-ner, 1988 | gas phase; B |
Free energy of reaction
| ΔrG° (kcal/mol) | T (K) | Method | Reference | Comment |
|---|---|---|---|---|
| 3.6 | 250. | PHPMS | Meot-ner, 1988 | gas phase; Entropy change calculated or estimated, DG<, ΔrH<; M |
+
= (
•
)
By formula: C5H5- + C7H8O = (C5H5- • C7H8O)
| Quantity | Value | Units | Method | Reference | Comment |
|---|---|---|---|---|---|
| ΔrH° | 19.2 ± 1.0 | kcal/mol | TDAs | Meot-ner, 1988 | gas phase; B,M |
| Quantity | Value | Units | Method | Reference | Comment |
| ΔrS° | 29.8 | cal/mol*K | PHPMS | Meot-ner, 1988 | gas phase; M |
| Quantity | Value | Units | Method | Reference | Comment |
| ΔrG° | 10.3 ± 1.0 | kcal/mol | TDAs | Meot-ner, 1988 | gas phase; B |
+
= C5H5Co-
By formula: C5H5- + Co = C5H5Co-
| Quantity | Value | Units | Method | Reference | Comment |
|---|---|---|---|---|---|
| ΔrH° | 7.00 ± 0.60 | kcal/mol | N/A | Sunderlin and Squires, 1999 | gas phase; B |
+
= (
•
)
By formula: C5H5- + H2O = (C5H5- • H2O)
| Quantity | Value | Units | Method | Reference | Comment |
|---|---|---|---|---|---|
| ΔrH° | 11.0 ± 1.0 | kcal/mol | TDAs | Meot-ner, 1988 | gas phase; B,M |
| Quantity | Value | Units | Method | Reference | Comment |
| ΔrS° | 16.1 | cal/mol*K | PHPMS | Meot-ner, 1988 | gas phase; M |
| Quantity | Value | Units | Method | Reference | Comment |
| ΔrG° | 6.2 ± 1.0 | kcal/mol | TDAs | Meot-ner, 1988 | gas phase; B |
( •
) +
= (
• 2
)
By formula: (C5H5- • H2O) + H2O = (C5H5- • 2H2O)
| Quantity | Value | Units | Method | Reference | Comment |
|---|---|---|---|---|---|
| ΔrH° | 10.0 | kcal/mol | PHPMS | Meot-ner, 1988 | gas phase; M |
| Quantity | Value | Units | Method | Reference | Comment |
| ΔrS° | 17.4 | cal/mol*K | PHPMS | Meot-ner, 1988 | gas phase; M |
References
Go To: Top, Reaction thermochemistry data, Gas phase ion energetics data, Ion clustering data, Notes
Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.
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]
Cumming and Kebarle, 1978
Cumming, J.B.; Kebarle, P.,
Summary of gas phase measurements involving acids AH. Entropy changes in proton transfer reactions involving negative ions. Bond dissociation energies D(A-H) and electron affinities EA(A),
Can. J. Chem., 1978, 56, 1. [all data]
Engelking and Lineberger, 1977
Engelking, P.C.; Lineberger, W.C.,
Laser photoelectron spectrometry of C5H5-: A determination of the electron affinity and Jahn-Teller coupling in cyclopentadienyl,
J. Chem. Phys., 1977, 67, 1412. [all data]
Meot-ner, 1988
Meot-ner, M.,
The Ionic Hydrogen Bond and Solvation. 7. Interaction Energies of Carbanions with Solvent Molecules,
J. Am. Chem. Soc., 1988, 110, 12, 3858, https://doi.org/10.1021/ja00220a022
. [all data]
Sunderlin and Squires, 1999
Sunderlin, L.S.; Squires, R.R.,
Bond strengths in cyclopentadienyl metal carbonyl anions,
Int. J. Mass Spectrom., 1999, 183, 149-161, https://doi.org/10.1016/S1387-3806(98)14230-6
. [all data]
Notes
Go To: Top, Reaction thermochemistry data, Gas phase ion energetics data, Ion clustering data, References
- Symbols used in this document:
T Temperature ΔrG° Free energy of reaction at standard conditions ΔrH° Enthalpy of reaction at standard conditions ΔrS° Entropy of reaction at standard conditions - Data from NIST Standard Reference Database 69: NIST Chemistry WebBook
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