Caesium iodide

<h2 id="synthesis-and-structure">Synthesis and structure</h2>

<p>Bulk caesium iodide crystals have the cubic CsCl crystal structure, but the structure type of nanometer-thin CsI films depends on the substrate material – it is CsCl for <a href="/facts/Mica/ag4cdnsb">mica</a> and NaCl for LiF, NaBr and NaCl substrates.<a class="footnote-ref" id="fnref:2" href="#fn:2"><sup>2</sup></a>
</p><p>Caesium iodide atomic chains can be grown inside double-wall <a href="/facts/Carbon_nanotube/atuDPPaG">carbon nanotubes</a>. In such chains I atoms appear brighter than Cs atoms in electron micrographs despite having a smaller mass. This difference was explained by the charge difference between Cs atoms (positive), inner nanotube walls (negative) and I atoms (negative). As a result, Cs atoms are attracted to the walls and vibrate more strongly than I atoms, which are pushed toward the nanotube axis.<a class="footnote-ref" id="fnref:3" href="#fn:3"><sup>3</sup></a>
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<h2 id="properties">Properties</h2>
Solubility of Csl in water<a class="footnote-ref" id="fnref:4" href="#fn:4"><sup>4</sup></a><table><tbody><tr><th>Т (°C)</th><th>0</th><th>10</th><th>20</th><th>25</th><th>30</th><th>40</th><th>50</th><th>60</th><th>70</th><th>80</th><th>90</th><th>100</th></tr><tr><td>S (wt%)</td><td>30.9</td><td>37.2</td><td>43.2</td><td>45.9</td><td>48.6</td><td>53.3</td><td>57.3</td><td>60.7</td><td>63.6</td><td>65.9</td><td>67.7</td><td>69.2</td></tr></tbody></table>
<h2 id="applications">Applications</h2>
<p>An important application of caesium iodide <a href="/facts/Crystals/e2R2mk3E">crystals</a>, which are <a href="/facts/Scintillator/vhxA1Ufo">scintillators</a>, is electromagnetic <a href="/facts/Calorimeter_(particle_physics)/FCA2evfS">calorimetry</a> in experimental <a href="/facts/Particle_physics/YgIuyj2t">particle physics</a>. Pure CsI is a fast and dense scintillating material with relatively low light yield that increases significantly with cooling,<a class="footnote-ref" id="fnref:5" href="#fn:5"><sup>5</sup></a> and a fairly small <a href="/facts/Moli%C3%A8re_radius/I4oobbsz">Molière radius</a> is 3.5 cm. It exhibits two main emission components: one in the near <a href="/facts/Ultraviolet/kncBUqn5">ultraviolet</a> region at the <a href="/facts/Wavelength/kcJU0ymz">wavelength</a> of 310 <a href="/facts/Nanometer/a98sjHyu">nm</a> and one at 460 nm. The drawbacks of CsI are a high <a href="/facts/Temperature_gradient/YhWj21zy">temperature gradient</a> and a slight <a href="/facts/Hygroscopicity/1NBGewXv">hygroscopicity</a>.
</p><p>Caesium iodide is used as a beamsplitter in <a href="/facts/Fourier_transform_spectroscopy/qFSjz3Xe">Fourier transform infrared</a> (FTIR) spectrometers. It has a wider transmission range than the more common <a href="/facts/Potassium_bromide/mGWPW1zd">potassium bromide</a> beamsplitters, working range into the far infrared. However, optical-quality CsI crystals are very soft and hard to cleave or polish. They should also be coated (typically with germanium) and stored in a desiccator, to minimize interaction with atmospheric water vapors.<a class="footnote-ref" id="fnref:6" href="#fn:6"><sup>6</sup></a>
</p><p>In addition to image intensifier input phosphors, caesium iodide is often also used in medicine as the scintillating material in <a href="/facts/Flat_panel_detector/CtxzbvGM">flat panel x-ray detectors</a>.<a class="footnote-ref" id="fnref:7" href="#fn:7"><sup>7</sup></a>
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<h2 id="cited-sources">Cited sources</h2>
<ul><li>Haynes, William M., ed. (2011). <i><a href="/facts/CRC_Handbook_of_Chemistry_and_Physics/qjxzC2Cu">CRC Handbook of Chemistry and Physics</a></i> (92nd ed.). Boca Raton, Florida: <a href="/facts/CRC_Press/duTuH4hz">CRC Press</a>. <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 1-4398-5511-0.</li></ul>

<h2 id="references">References</h2>

<ol>
<li id="fn:1"><p>Kowalski, M. P.; Fritz, G. G.; Cruddace, R. G.; Unzicker, A. E.; Swanson, N. (1986). "Quantum efficiency of cesium iodide photocathodes at soft x-ray and extreme ultraviolet wavelengths". Applied Optics. 25 (14): 2440. Bibcode:1986ApOpt..25.2440K. doi:10.1364/AO.25.002440. PMID 18231513. <a href="/wiki/Bibcode_(identifier)" target="_blank">/wiki/Bibcode_(identifier)</a> <a href="#fnref:1" class="footnote-back-ref">↩</a></p></li>
<li id="fn:2"><p>Schulz, L. G. (1951). "Polymorphism of cesium and thallium halides". Acta Crystallographica. 4 (6): 487–489. Bibcode:1951AcCry...4..487S. doi:10.1107/S0365110X51001641. <a href="/wiki/Bibcode_(identifier)" target="_blank">/wiki/Bibcode_(identifier)</a> <a href="#fnref:2" class="footnote-back-ref">↩</a></p></li>
<li id="fn:3"><p>Senga, Ryosuke; Komsa, Hannu-Pekka; Liu, Zheng; Hirose-Takai, Kaori; Krasheninnikov, Arkady V.; Suenaga, Kazu (2014). "Atomic structure and dynamic behaviour of truly one-dimensional ionic chains inside carbon nanotubes". Nature Materials. 13 (11): 1050–4. Bibcode:2014NatMa..13.1050S. doi:10.1038/nmat4069. PMID 25218060. <a href="/wiki/Bibcode_(identifier)" target="_blank">/wiki/Bibcode_(identifier)</a> <a href="#fnref:3" class="footnote-back-ref">↩</a></p></li>
<li id="fn:4"><p>Haynes, p. 5.191 <a href="#fnref:4" class="footnote-back-ref">↩</a></p></li>
<li id="fn:5"><p>Mikhailik, V.; Kapustyanyk, V.; Tsybulskyi, V.; Rudyk, V.; Kraus, H. (2015). "Luminescence and scintillation properties of CsI: A potential cryogenic scintillator". Physica Status Solidi B. 252 (4): 804–810. arXiv:1411.6246. Bibcode:2015PSSBR.252..804M. doi:10.1002/pssb.201451464. S2CID 118668972. <a href="/wiki/ArXiv_(identifier)" target="_blank">/wiki/ArXiv_(identifier)</a> <a href="#fnref:5" class="footnote-back-ref">↩</a></p></li>
<li id="fn:6"><p>Sun, Da-Wen (2009). Infrared Spectroscopy for Food Quality Analysis and Control. Academic Press. pp. 158–. ISBN 978-0-08-092087-0. <a href="978-0-08-092087-0" target="_blank">978-0-08-092087-0</a> <a href="#fnref:6" class="footnote-back-ref">↩</a></p></li>
<li id="fn:7"><p>Lança, Luís; Silva, Augusto (2012). "Digital Radiography Detectors: A Technical Overview" (PDF). Digital Imaging Systems for Plain Radiography. Springer. doi:10.1007/978-1-4614-5067-2_2. hdl:10400.21/1932. ISBN 978-1-4614-5066-5. Archived from the original (PDF) on 2019-01-28. Retrieved 2017-08-28. <a href="978-1-4614-5066-5" target="_blank">978-1-4614-5066-5</a> <a href="#fnref:7" class="footnote-back-ref">↩</a></p></li>
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Caesium iodide open-in-new

Caesium iodide