Apatite Thermochemistry: the Simple Salt Approximation

Drouet has recently comprehensively reviewed the thermochemistry of phosphate apatites, M10(PO4)6X2. On the basis of the data assembled, he has established an optimized additive set of data values based upon the component ions, M2+, P2O5, or PO43–, and halide or OH– ions, which yield phosphoapatite...

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Main Author: Glasser, Leslie
Format: Journal Article
Published: American Chemical Society 2019
Online Access:http://hdl.handle.net/20.500.11937/76416
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author Glasser, Leslie
author_facet Glasser, Leslie
author_sort Glasser, Leslie
building Curtin Institutional Repository
collection Online Access
description Drouet has recently comprehensively reviewed the thermochemistry of phosphate apatites, M10(PO4)6X2. On the basis of the data assembled, he has established an optimized additive set of data values based upon the component ions, M2+, P2O5, or PO43–, and halide or OH– ions, which yield phosphoapatite enthalpy and Gibbs energy values generally within 1% of their experimental values. In this paper, we introduce and compare the Simple Salt Approximation (SSA) for generation of the same thermodynamic values by addition of values for the component salts of the apatite. SSA is widely applicable to ionic systems so that familiarity with this procedure is worthwhile. Drouet’s additive values focused on phosphoapatites yield better results (at 1%) than does the more general SSA (at ∼3%), but the SSA provides an alternative to data prediction when the Drouet additive factors are not available. In addition, we here use the SSA to generate approximate entropy values and estimate the Debye temperature of phosphoapatites under ambient conditions, yielding insight into the extent of activation of their vibrational modes.
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spelling curtin-20.500.11937-764162019-10-03T07:48:48Z Apatite Thermochemistry: the Simple Salt Approximation Glasser, Leslie Drouet has recently comprehensively reviewed the thermochemistry of phosphate apatites, M10(PO4)6X2. On the basis of the data assembled, he has established an optimized additive set of data values based upon the component ions, M2+, P2O5, or PO43–, and halide or OH– ions, which yield phosphoapatite enthalpy and Gibbs energy values generally within 1% of their experimental values. In this paper, we introduce and compare the Simple Salt Approximation (SSA) for generation of the same thermodynamic values by addition of values for the component salts of the apatite. SSA is widely applicable to ionic systems so that familiarity with this procedure is worthwhile. Drouet’s additive values focused on phosphoapatites yield better results (at 1%) than does the more general SSA (at ∼3%), but the SSA provides an alternative to data prediction when the Drouet additive factors are not available. In addition, we here use the SSA to generate approximate entropy values and estimate the Debye temperature of phosphoapatites under ambient conditions, yielding insight into the extent of activation of their vibrational modes. 2019 Journal Article http://hdl.handle.net/20.500.11937/76416 10.1021/acs.inorgchem.9b02343 American Chemical Society restricted
spellingShingle Glasser, Leslie
Apatite Thermochemistry: the Simple Salt Approximation
title Apatite Thermochemistry: the Simple Salt Approximation
title_full Apatite Thermochemistry: the Simple Salt Approximation
title_fullStr Apatite Thermochemistry: the Simple Salt Approximation
title_full_unstemmed Apatite Thermochemistry: the Simple Salt Approximation
title_short Apatite Thermochemistry: the Simple Salt Approximation
title_sort apatite thermochemistry: the simple salt approximation
url http://hdl.handle.net/20.500.11937/76416