Published 2020-01-01
“…Halilsarpite is isostructural
with walentaite and natrowalentaite, which have structures based on
heteropolyhedral layers of configuration
[<span class="inline-formula"><i>M</i>1(<i>M</i>2)<sub>2</sub></span>(<span class="inline-formula"><i>T</i></span><span class="inline-formula">O<sub>4</sub></span>)<span class="inline-formula"><sub>2</sub></span>(O,OH)<span class="inline-formula"><sub>6</sub></span>] with surface-attached
<span class="inline-formula">As<sup>3+</sup></span><span class="inline-formula">O<sub>3</sub></span> groups and <span class="inline-formula">Ca</span> and <span class="inline-formula">Na</span> cations, and with interlayer hydrated
cations and <span class="inline-formula">H<sub>2</sub>O</span>
molecules. The octahedrally coordinated sites <span class="inline-formula"><i>M</i>1</span> and <span class="inline-formula"><i>M</i>2</span> are occupied by <span class="inline-formula">Fe<sup>3+</sup></span> in walentaite, while <span class="inline-formula"><i>M</i>2 =</span> <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M49" display="inline" overflow="scroll" dspmath="mathml"><mrow class="chem"><msubsup><mi mathvariant="normal">Fe</mi><mn mathvariant="normal">0.67</mn><mrow><mn mathvariant="normal">3</mn><mo>+</mo></mrow></msubsup></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="30pt" height="17pt" class="svg-formula" dspmath="mathimg" md5hash="bf66f2bce39194a30ac0e2b60f8eff65"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="ejm-32-89-2020-ie00009.svg" width="30pt" height="17pt" src="ejm-32-89-2020-ie00009.png"/></svg:svg></span></span><span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M50" display="inline" overflow="scroll" dspmath="mathml"><mrow class="chem"><msubsup><mi mathvariant="normal">W</mi><mn mathvariant="normal">0.33</mn><mrow><mn mathvariant="normal">6</mn><mo>+</mo></mrow></msubsup></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="28pt" height="17pt" class="svg-formula" dspmath="mathimg" md5hash="90c9357d5ebcc468559246da33d0084c"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="ejm-32-89-2020-ie00010.svg" width="28pt" height="17pt" src="ejm-32-89-2020-ie00010.png"/></svg:svg></span></span> in natrowalentaite. …”
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