<?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:creator>D. Kirk Nordstrom</dc:creator>
  <dc:date>2022</dc:date>
  <dc:description>&lt;div class="abstract-content"&gt;&lt;div class="abstract" data-abstract-type="normal"&gt;&lt;p&gt;Thermodynamic data are constrained by the interrelated thermodynamic equations in addition to the observational measurements and their uncertainties. The consequence is a network of thermodynamic properties that can be evaluated for their internal consistency. In this study, three fluoride minerals that can cause high fluoride concentrations in groundwaters are evaluated for their solubilities and their internal thermodynamic consistency with calorimetric, isopiestic and electrochemical measurements: fluorite, CaF&lt;span class="sub"&gt;2&lt;/span&gt;, cryolite, Na&lt;span class="sub"&gt;3&lt;/span&gt;AlF&lt;span class="sub"&gt;6&lt;/span&gt;, and villiaumite, NaF. This evaluation involves the three solids and 13 aqueous species, the free ions of Ca&lt;span class="sup"&gt;2+&lt;/span&gt;, Na&lt;span class="sup"&gt;+&lt;/span&gt;, Al&lt;span class="sup"&gt;3+&lt;/span&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;and F&lt;span class="sup"&gt;–&lt;/span&gt;, and the hydroxido and fluorido complexes of Al&lt;span class="sup"&gt;3+&lt;/span&gt;, and the CaF&lt;span class="sup"&gt;+&lt;/span&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;ion pair. For the fluorite–cryolite–villiaumite–aqueous species network, the number of components is minimal, and the solubility studies are mostly of high quality. Re-evaluations of original data using&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;span class="italic"&gt;PHREEQC&lt;/span&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;helps to broaden the quantitative evaluation of thermodynamic properties and to resolve apparent discrepancies. A check on this thermodynamic network shows that through a careful appraisal of the literature, a highly consistent set of values can be derived. The resultant infinite-dilution solubility-product constants at 25°C and 1 bar are: for fluorite solubility, log&lt;span class="italic"&gt;K&lt;/span&gt;&lt;span class="sub"&gt;sp&lt;/span&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;= –10.57 ± 0.08; for cryolite solubility, log&lt;span class="italic"&gt;K&lt;/span&gt;&lt;span class="sub"&gt;sp&lt;/span&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;= –33.9 ± 0.2; and for villiaumite solubility, log&lt;span class="italic"&gt;K&lt;/span&gt;&lt;span class="sub"&gt;sp&lt;/span&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;= –0.4981 ± 0.003.&lt;/p&gt;&lt;/div&gt;&lt;/div&gt;</dc:description>
  <dc:format>application/pdf</dc:format>
  <dc:identifier>10.1180/mgm.2022.40</dc:identifier>
  <dc:language>en</dc:language>
  <dc:publisher>Cambridge University Press</dc:publisher>
  <dc:title>Evaluation for internal consistency in the thermodynamic network involving fluorite, cryolite and villiaumite solubilities and aqueous species at 25°C and 1 bar</dc:title>
  <dc:type>article</dc:type>
</oai_dc:dc>