<?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>Sumedha Jayanetti</dc:contributor>
  <dc:contributor>Alan J. Anderson</dc:contributor>
  <dc:contributor>William A. Bassett</dc:contributor>
  <dc:contributor>I.-M. Chou</dc:contributor>
  <dc:creator>Robert A. Mayanovic</dc:creator>
  <dc:date>2002</dc:date>
  <dc:description>&lt;p&gt;&lt;span&gt;We report here on X-ray absorption fine structure (XAFS) measurements used to determine the structure of the Yb&lt;/span&gt;&lt;span&gt;3+&lt;/span&gt;&lt;span&gt;&amp;nbsp;ion in aqueous solutions over a range of temperatures from 25 to 500 &amp;deg;C and pressures up to 270 MPa. Fluorescence Yb&amp;nbsp;&lt;/span&gt;&lt;i&gt;L&lt;/i&gt;&lt;span&gt;3&lt;/span&gt;&lt;span&gt;-edge spectra were collected separately from nitrate (0.006&lt;/span&gt;&lt;i&gt;m&lt;/i&gt;&lt;span&gt;&amp;nbsp;Yb/0.16&lt;/span&gt;&lt;i&gt;m&lt;/i&gt;&lt;span&gt;&amp;nbsp;HNO&lt;/span&gt;&lt;span&gt;3&lt;/span&gt;&lt;span&gt;) and chloride (0.006&amp;nbsp;&lt;/span&gt;&lt;i&gt;m&lt;/i&gt;&lt;span&gt;&amp;nbsp;YbCl&lt;/span&gt;&lt;span&gt;3&lt;/span&gt;&lt;span&gt;/0.017&amp;nbsp;&lt;/span&gt;&lt;i&gt;m&lt;/i&gt;&lt;span&gt;&amp;nbsp;HCl) aqueous solutions within a hydrothermal diamond anvil cell. The Yb&amp;minus;O distance of the Yb&lt;/span&gt;&lt;span&gt;3+&lt;/span&gt;&lt;span&gt;aquo ion in the nitrate solution exhibits a uniform reduction at a rate of 0.02 &amp;Aring;/100 &amp;deg;C, whereas the number of oxygens decreases from 8.3 &amp;plusmn; 0.6 to 4.8 &amp;plusmn; 0.7, in going from 25 to 500 &amp;deg;C. No evidence for nitrate complexes was found from measurements made on this solution. The Yb&lt;/span&gt;&lt;span&gt;3+&lt;/span&gt;&lt;span&gt;&amp;nbsp;is found to persist as an aquo ion up to 150 &amp;deg;C in the chloride aqueous solution. In the 300&amp;minus;500 &amp;deg;C range, chloro complexes are found to occur in the solution, most likely of the type Yb(H&lt;/span&gt;&lt;span&gt;2&lt;/span&gt;&lt;span&gt;O)&lt;/span&gt;&lt;span&gt;&amp;delta;&lt;/span&gt;&lt;span&gt;-&lt;/span&gt;&lt;i&gt;&lt;span&gt;n&lt;/span&gt;&lt;/i&gt;&lt;span&gt;Cl&lt;/span&gt;&lt;i&gt;&lt;span&gt;n&lt;/span&gt;&lt;/i&gt;&lt;span&gt;+3-&lt;/span&gt;&lt;i&gt;&lt;span&gt;n&lt;/span&gt;&lt;/i&gt;&lt;span&gt;&amp;nbsp;(&amp;delta; &amp;asymp; 7). The Yb&amp;minus;Cl distance of the chloro ytterbium(III) complexes is found to decrease uniformly at a rate of about 0.02 &amp;Aring;/100 &amp;deg;C, whereas the number of chlorines increases from 0.5 &amp;plusmn; 0.3 to 1.8 &amp;plusmn; 0.2 in the 300&amp;minus;500 &amp;deg;C temperature range. Conversely, the Yb&amp;minus;O distance undergoes a lower uniform reduction at a rate of 0.007 &amp;Aring;/100 &amp;deg;C, whereas the number of oxygens decreases from 8.3 &amp;plusmn; 0.5 to 5.1 &amp;plusmn; 0.3 in going from 25 to 500 &amp;deg;C in the same solution.&lt;/span&gt;&lt;/p&gt;</dc:description>
  <dc:format>application/pdf</dc:format>
  <dc:identifier>10.1021/jp020140q</dc:identifier>
  <dc:language>en</dc:language>
  <dc:publisher>ACS Publications</dc:publisher>
  <dc:title>The structure of Yb&lt;sup&gt;3+&lt;/sup&gt; aquo ion and chloro complexes in aqueous solutions at up to 500 °C and 270 MPa</dc:title>
  <dc:type>article</dc:type>
</oai_dc:dc>