Cesium Iodide (CAS No. 7789-17-5)
Cesium iodide is a soft material with extremely strong hygroscopic properties. Its scintillation crystals are widely used in indirect X-ray imaging detectors, such as those employed in CT scanning systems. It is also utilized in the construction of electromagnetic shower detectors for the CLEO II experiment, which studies electron–positron annihilation at center-of-mass energies around 10 GeV. In addition, cesium iodide is used in beam splitters for far-infrared spectrophotometers and as transmission windows for IR applications.
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Cesium iodide Chemical Properties
| Melting point | 626 °C (lit.) |
| Boiling point | 1280 °C |
| density | 4.51 g/mL at 25 °C (lit.) |
| refractive index | 1.7876 |
| Fp | 1280°C |
| storage temp. | Keep in dark place,Inert atmosphere,Room temperature |
| solubility | soluble in ethanol, methanol, acetone |
| form | beads |
| Specific Gravity | 4.51 |
| color | White |
| PH | pH(50g/l, 25℃) : 5.0～9.0 |
| Water Solubility | 74 g/100 mL (20 ºC) |
| Sensitive | Hygroscopic |
| Merck | 142014 |
| Exposure limits | ACGIH: TWA 0.01 ppm |
| Dielectric constant | 5.6（Ambient） |
| Stability: | Stable. Deliquescent. |
| Major Application | cleaning products |
| cosmetics |
| flavors and fragrances |
| food and beverages |
| personal care |
| InChI | 1S/Cs.HI/h;1H/q+1;/p-1 |
| InChIKey | XQPRBTXUXXVTKB-UHFFFAOYSA-M |
| SMILES | [I-].[Cs+] |
| CAS DataBase Reference | 7789-17-5(CAS DataBase Reference) |
| NIST Chemistry Reference | Cesium iodide(7789-17-5) |
| EPA Substance Registry System | Cesium iodide (CsI) (7789-17-5) |
Safety Information
| Hazard Codes | Xn,Xi |
| Risk Statements | 36/37/38-42/43-43 |
| Safety Statements | 22-36/37-45 |
| RIDADR | UN 3077 9 / PGIII |
| WGK Germany | 2 |
| RTECS | FL0350000 |
| F | 8 |
| TSCA | TSCA listed |
| HazardClass | 9 |
| HS Code | 28276000 |
| Storage Class | 13 - Non Combustible Solids |
| Hazard Classifications | Aquatic Acute 1 |
| Repr. 2 |
| Toxicity | LD50 i.p. in rats: 1.4 g/kg (Cochran) |
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Product Applications of Cesium Iodide (CAS No. 7789-17-5)
Cesium iodide (CsI) is an ionic compound widely used as a scintillator material in applications such as X-ray image intensifier tubes, photocathodes, and display devices. It is also employed in scintillation (Geiger) counters for measuring external radiation levels, and serves as a “getter” to remove residual air molecules in vacuum tubes.
Due to its relatively high density and atomic number, CsI provides strong γ-ray stopping power. For scintillation counting, it can be used in its pure form or doped with sodium or thallium.
In addition, CsI exhibits good resistance to thermal and mechanical shock, and its physical properties remain stable regardless of the activator used. Compared with NaI(Tl), it is softer, more plastic, and does not cleave, giving it excellent durability. These characteristics make it particularly suitable for well logging, space research, and other demanding environments involving severe shock conditions.
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