Methyl ammonium aluminum alum
- Formula: CH6AlNO8S2·H24O12
- Molecular weight: 467.355
- CAS Registry Number: 15243-18-2
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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.
Data compiled by: Eugene S. Domalski and Elizabeth D. Hearing
| Quantity | Value | Units | Method | Reference | Comment |
|---|---|---|---|---|---|
| S°solid,1 bar | 182.6 | cal/mol*K | N/A | Ashworth and Steeple, 1968 |
Constant pressure heat capacity of solid
| Cp,solid (cal/mol*K) | Temperature (K) | Reference | Comment |
|---|---|---|---|
| 188.2 | 300. | Ashworth and Steeple, 1968 | T = 5 to 300 K. |
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 by: Eugene S. Domalski and Elizabeth D. Hearing
Temperature of phase transition
| Ttrs (K) | Initial Phase | Final Phase | Reference | Comment |
|---|---|---|---|---|
| 176.18 | crystaline, II | crystaline, I | Ashworth and Steeple, 1968 | S = 9.70 J/mol*K 90 K Anomaly: Schottky type anomaly between 65 and 120 K, maximum at 90 K, entropy estimated to be between 6 and 9 J/mol*K. 176 K Anomaly: Due to free rotation of methylammonium group (CH3NH3); observed entropy change at 176.18 K is 9.70 J/mol*K. |
References
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Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.
Ashworth and Steeple, 1968
Ashworth, T.; Steeple, H.,
The continuous heating method of calorimetry and its application to the study of low temperature specific heat anomalies in methyl-ammonium alum,
Cryogenics, 1968, 8, 225-234. [all data]
Notes
Go To: Top, Condensed phase thermochemistry data, Phase change data, References
- Symbols used in this document:
Cp,solid Constant pressure heat capacity of solid S°solid,1 bar Entropy of solid at standard conditions (1 bar) Ttrs Temperature of phase transition - Data from NIST Standard Reference Database 69: NIST Chemistry WebBook
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