<?xml version='1.0' encoding='utf-8'?>
<oai_dc:dc xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:oai_dc="http://www.openarchives.org/OAI/2.0/oai_dc/" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.openarchives.org/OAI/2.0/oai_dc/ http://www.openarchives.org/OAI/2.0/oai_dc.xsd">
  <dc:contributor>R. A. Robie</dc:contributor>
  <dc:contributor>J.A. Kittrick</dc:contributor>
  <dc:creator>B. S. Hemingway</dc:creator>
  <dc:date>1978</dc:date>
  <dc:description>&lt;p&gt;Solution calorimetric measurements compared with solubility determinations from the literature for the same samples of gibbsite have provided a direct thermochemical cycle through which the Gibbs free energy of formation of [Al(OH)&lt;sub&gt;4 aq&lt;/sub&gt;&lt;sup&gt;−&lt;/sup&gt;] can be determined. The Gibbs free energy of formation of [Al(OH)&lt;sub&gt;4 aq&lt;/sub&gt;&lt;sup&gt;−&lt;/sup&gt;] at 298.15 K is −1305 ± 1 kJ/mol. These heat-of-solution results show no significant difference in the thermodynamic properties of gibbsite particles in the range from 50 to 0.05 μm.&lt;/p&gt;&lt;p&gt;The Gibbs free energies of formation at 298.15 K and 1 bar pressure of diaspore, boehmite and bayerite are −9210 ± 5.0, −918.4 ± 2.1 and −1153 ± 2 kJ/mol based upon the Gibbs free energy of [A1(OH)&lt;sub&gt;4 aq&lt;/sub&gt;&lt;sup&gt;−&lt;/sup&gt;] calculated in this paper and the acceptance of −1582.2 ± 1.3 and −1154.9 ± 1.2 kJ/mol for the Gibbs free energy of formation of corundum and gibbsite, respectively.&lt;/p&gt;&lt;p&gt;Values for the Gibbs free energy formation of [Al(OH)&lt;sub&gt;2 aq&lt;/sub&gt;&lt;sup&gt;+&lt;/sup&gt;] and [AlO&lt;sub&gt;2 aq&lt;/sub&gt;&lt;sup&gt;−&lt;/sup&gt;] were also calculated as −914.2 ± 2.1 and −830.9 ± 2.1 kJ/mol, respectively. The use of [AlC&lt;sub&gt;2 aq&lt;/sub&gt;&lt;sup&gt;−&lt;/sup&gt;] as a chemical species is discouraged.&lt;/p&gt;&lt;p&gt;A revised Gibbs free energy of formation for [H&lt;sub&gt;4&lt;/sub&gt;SiO&lt;sub&gt;4aq&lt;/sub&gt;&lt;sup&gt;0&lt;/sup&gt;] was recalculated from calorimetric data yielding a value of −1307.5 ± 1.7 kJ/mol which is in good agreement with the results obtained from several solubility studies.&lt;/p&gt;&lt;p&gt;Smoothed values for the thermodynamic functions&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;i&gt;C&lt;/i&gt;&lt;sub&gt;&lt;i&gt;P&lt;/i&gt;&lt;/sub&gt;&lt;sup&gt;0&lt;/sup&gt;, (&lt;span class="math"&gt;&lt;span id="MathJax-Element-1-Frame" class="MathJax_SVG" data-mathml="&lt;math xmlns=&amp;quot;http://www.w3.org/1998/Math/MathML&amp;quot;&gt;&lt;mtext&gt;H&lt;/mtext&gt;&lt;msub&gt;&lt;mi&gt;&lt;/mi&gt;&lt;mn&gt;T&lt;/mn&gt;&lt;/msub&gt;&lt;msup&gt;&lt;mi&gt;&lt;/mi&gt;&lt;mn&gt;0&lt;/mn&gt;&lt;/msup&gt;&lt;mtext&gt;- H&lt;/mtext&gt;&lt;msub&gt;&lt;mi&gt;&lt;/mi&gt;&lt;mn&gt;298&lt;/mn&gt;&lt;/msub&gt;&lt;msup&gt;&lt;mi&gt;&lt;/mi&gt;&lt;mn&gt;0&lt;/mn&gt;&lt;/msup&gt;&lt;mtext&gt;)&lt;/mtext&gt;&lt;mtext&gt;T&lt;/mtext&gt;&lt;/math&gt;"&gt;&lt;span class="MJX_Assistive_MathML"&gt;HT0- H2980)T&lt;/span&gt;&lt;/span&gt;&lt;/span&gt;,&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;span class="math"&gt;&lt;span id="MathJax-Element-2-Frame" class="MathJax_SVG" data-mathml="&lt;math xmlns=&amp;quot;http://www.w3.org/1998/Math/MathML&amp;quot;&gt;&lt;mtext&gt;(&lt;/mtext&gt;&lt;mtext&gt;G&lt;/mtext&gt;&lt;msub&gt;&lt;mi&gt;&lt;/mi&gt;&lt;mn&gt;T&lt;/mn&gt;&lt;/msub&gt;&lt;msup&gt;&lt;mi&gt;&lt;/mi&gt;&lt;mn&gt;0&lt;/mn&gt;&lt;/msup&gt;&lt;mtext&gt;- H&lt;/mtext&gt;&lt;msub&gt;&lt;mi&gt;&lt;/mi&gt;&lt;mn&gt;298&lt;/mn&gt;&lt;/msub&gt;&lt;msup&gt;&lt;mi&gt;&lt;/mi&gt;&lt;mn&gt;0&lt;/mn&gt;&lt;/msup&gt;&lt;mtext&gt;)&lt;/mtext&gt;&lt;mtext&gt;T&lt;/mtext&gt;&lt;/math&gt;"&gt;&lt;span class="MJX_Assistive_MathML"&gt;(GT0- H2980)T&lt;/span&gt;&lt;/span&gt;&lt;/span&gt;,&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;i&gt;S&lt;/i&gt;&lt;sub&gt;&lt;i&gt;T&lt;/i&gt;&lt;/sub&gt;&lt;sup&gt;0&lt;/sup&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;-&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;i&gt;S&lt;/i&gt;&lt;sub&gt;0&lt;/sub&gt;&lt;sup&gt;0&lt;/sup&gt;,&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;span class="math"&gt;&lt;span id="MathJax-Element-3-Frame" class="MathJax_SVG" data-mathml="&lt;math xmlns=&amp;quot;http://www.w3.org/1998/Math/MathML&amp;quot;&gt;&lt;mtext&gt;&amp;amp;#x394;H&lt;/mtext&gt;&lt;msub&gt;&lt;mi&gt;&lt;/mi&gt;&lt;mn&gt;&amp;amp;#x192;,298&lt;/mn&gt;&lt;/msub&gt;&lt;msup&gt;&lt;mi&gt;&lt;/mi&gt;&lt;mn&gt;0&lt;/mn&gt;&lt;/msup&gt;&lt;/math&gt;"&gt;ƒ&lt;span class="MJX_Assistive_MathML"&gt;ΔHƒ,2980&lt;/span&gt;&lt;/span&gt;&lt;/span&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;kaolinite are listed at integral temperatures between 298.15 and 800 K. The heat capacity of kaolinite at temperatures between 250 and 800 K may be calculated from the following equation:&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;i&gt;C&lt;/i&gt;&lt;sub&gt;&lt;i&gt;P&lt;/i&gt;&lt;/sub&gt;&lt;sup&gt;0&lt;/sup&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;= 1430.26 − 0.78850&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;i&gt;T&lt;/i&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;+ 3.0340 × 10&lt;sup&gt;−4&lt;/sup&gt;&lt;i&gt;T&lt;/i&gt;&lt;sup&gt;2&lt;/sup&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;−1.85158 × 10&lt;sup&gt;−4&lt;/sup&gt;&lt;i&gt;T&lt;/i&gt;&lt;sup&gt;2&lt;/sup&gt;&lt;span class="math"&gt;&lt;span id="MathJax-Element-4-Frame" class="MathJax_SVG" data-mathml="&lt;math xmlns=&amp;quot;http://www.w3.org/1998/Math/MathML&amp;quot;&gt;&lt;mtext&gt;1&lt;/mtext&gt;&lt;mtext&gt;2&lt;/mtext&gt;&lt;mtext&gt;+ 8.3341 &amp;amp;#xD7; 10&lt;/mtext&gt;&lt;msup&gt;&lt;mi&gt;&lt;/mi&gt;&lt;mn&gt;6&lt;/mn&gt;&lt;/msup&gt;&lt;mtext&gt;T&lt;/mtext&gt;&lt;msup&gt;&lt;mi&gt;&lt;/mi&gt;&lt;mn&gt;&amp;amp;#x2212;2&lt;/mn&gt;&lt;/msup&gt;&lt;/math&gt;"&gt;&lt;span class="MJX_Assistive_MathML"&gt;12+ 8.3341 × 106T−2&lt;/span&gt;&lt;/span&gt;&lt;/span&gt;.&lt;/p&gt;&lt;p&gt;The thermodynamic properties of most of the geologically important Al-bearing phases have been referenced to the same reference state for Al, namely gibbsite.&lt;/p&gt;</dc:description>
  <dc:format>application/pdf</dc:format>
  <dc:identifier>10.1016/0016-7037(78)90024-8</dc:identifier>
  <dc:language>en</dc:language>
  <dc:publisher>Elsevier</dc:publisher>
  <dc:title>Revised values for the Gibbs free energy of formation of [Al(OH)4 aq-], diaspore, boehmite and bayerite at 298.15 K and 1 bar, the thermodynamic properties of kaolinite to 800 K and 1 bar, and the heats of solution of several gibbsite samples</dc:title>
  <dc:type>article</dc:type>
</oai_dc:dc>