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<div class="moz-cite-prefix">Dear Fabio!</div>
<div class="moz-cite-prefix"><br>
</div>
<div class="moz-cite-prefix">On 2021-08-10 01:17, Fabio Ramos Dias
de Andrade wrote:<br>
</div>
<blockquote type="cite"
cite="mid:CAG2u+AbfKyRZCdZ4mLaoTPVj7u0Snbfg5XSmh5Witzx5L5ORMA@mail.gmail.com">
<div>what is the meaning of 'At', in a formula such as </div>
<div><br>
</div>
<div>Reference code: 96-900-6365<br>
</div>
</blockquote>
<p>The reference code (aka database ID) does not seem to belong to
any of our curated or related databases (COD, PCOD, TCOD, AMCSD).</p>
<p>For the experimental databases (COD, AMCSD), the IDs are 7-digit
numbers, but you quote nine digits. We can not trace back that
data. Please either provide the COD ID for the data you are
working with, or the database designator from which you reference
code was taken; only then the data provenance can be established.<br>
</p>
<blockquote type="cite"
cite="mid:CAG2u+AbfKyRZCdZ4mLaoTPVj7u0Snbfg5XSmh5Witzx5L5ORMA@mail.gmail.com">
<div>Mineral name: Laumontite<br>
Compound name: Laumontite<br>
Common name: Laumontite<br>
Chemical formula: Si16.00Al8.00O48.00Ca4.00<b>At23.08</b>H37.60<br>
</div>
<div><br>
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</blockquote>
<p>Usually, "At" in CIFs means Astatine, or Astatium [1]. It is
strange however to see this element in such abundances in an X-ray
experimental structure, since all isotopes of AT are unstable, and
the most stable has half-life of just 8.3 hours [1]. It would be
difficult (although not impossible) to obtain crystals containing
At for long enough to measure their structure. For zeolites, of
course, At could be a "guest" component that was diffused rapidly
(as a solute or in gaseous form) into the structure and the
measured on a synchrotron or on a neutron source.</p>
<p>Another possibility could be that "At" is mistyped "Al", although
this is unlikely since Al is already present in the formula.</p>
<p>In any case you should refer to the original publication that
reported the structure – you should find there exact description
of the sample and its preparation.</p>
<p>Hope this helps!<br>
</p>
<p>Refs.:</p>
<p>[1] <a class="moz-txt-link-freetext" href="https://www.webelements.com/astatine/">https://www.webelements.com/astatine/</a> [2021-08-10
10:07:00+03:00]<br>
</p>
<pre class="moz-signature" cols="72">--
Dr. Saulius Gražulis
Vilnius University, Life Science Center, Institute of Biotechnology
Saulėtekio al. 7, LT-10257 Vilnius, Lietuva (Lithuania)
phone (office): (+370-5)-2234353, mobile: (+370-684)-49802, (+370-614)-36366
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