Bertoldi, C., Benisek, A., Cemic, L. and Dachs, E.
(2001)
*The heat capacity of two natural chlorite group minerals derived from differential scanning calorimetry*
Physics and Chemistry of Minerals, 28
(5).
pp. 332-336.
DOI 10.1007/s002690100157.

## Abstract

The heat capacity of natural chamosite (X-Fe = 0.889) and clinochlore (X-Fe = 0.116) were measured by differential scanning calorimetry (DSC). The samples were characterised by X-ray diffraction, microprobe analysis and Mossbauer spectroscopy. DSC measurements between 143 and 623 K were made following the procedure of Bosenick et al. (1996). The fitted data for natural chamosite (CA) in J mol-l K-L give: C-p.CA = 1224.3-10.685 x 10(3) x T-0.5 - 6.4389 x 10(6) x T-2 + 8.0279 x 10(8) x T-3 and for the natural clinochlore (CE): C-p.CE 1200.5-10.908 X 10(3) x T-0.5 -5.6941 x 10(6) x T-2 + 7.1166 x 10(8) x T-3. The corrected C-p-polynomial for pure end-member chamosite (Fe5Al)[Si3AlO10](OH)(8) is C-p.CAcor = 1248.3-11.116 X 10(3) x T-0.5 - 5.1623 x 10(6) x T-2 + 7.1867 x 10(8) x T-3 and the corrected C-p-polynomial for pure end-member clinochlore (Mg5Al)[Si3AlO10](OH)(8) is C-p.CEcor = 1191.3-10.665 x 10(3) x T-0.5 -6.5136 X 10(6) X T-2 + 7.7206 x 10(8) x T-3. The corrected C-p-polynomial for clinochlore is in excellent agreement with that in the internally consistent data sets of Berman (1988) and Holland and Powell (1998). The derived C-p-polynomial for chamosite (Cp.CAcor) leads to a 4.4% higher heat capacity, at 300 K, compared to that estimated by Holland and Powell (1998) based on a summation method. The corrected C-p-polynomial (C-p.CAcor) is, however, in excellent agreement with the computed C-p-polynomial given by Saccocia and Seyfried (1993), thus supporting the reliability of Berman and Brown's (1985) estimation method of heat capacities.

Document Type: | Article |
---|---|

Keywords: | chlorite group minerals heat capacity differential scanning calorimetry (DSC) consistent thermodynamic data system na2o-k2o-cao-mgo-feo-fe2o3-al2o3-sio2-tio2-h2o-co2 origin rocks |

Research affiliation: | Kiel University |

DOI etc.: | 10.1007/s002690100157 |

ISSN: | 0342-1791 |

Date Deposited: | 02 Feb 2012 07:24 |

Last Modified: | 08 Oct 2012 10:39 |

URI: | http://eprints.uni-kiel.de/id/eprint/16272 |

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