Caesium Iodide ( CsI ), Cesium Iodide - Properties and Applications


Caesium Iodide (CsI) is hygroscopic and readily dissolves in water. This property means that it needs to be kept away from water and also makes it difficult to polish.

Key Properties

Property Value
Density (g/cm3) 4.51
Melting Point (°C) 621
Young’s Modulus (GPa) 5.30
Dielectric Constant at 25 °C at 106 Hz 5.65
Co-Efficient of Thermal Expansion (m/m/°C at 20 °C) 39.1 x 10-6


Caesium Iodide is used to make cell windows and prisms for infrared application up to 50 µm.

It is also used in beam splitters for Fourier Transform Infra-Red (FTIR) devices. And in scintillators where it may or may not be doped with Thallium.


Tell Us What You Think

Do you have a review, update or anything you would like to add to this article?

Leave your feedback
Your comment type

While we only use edited and approved content for Azthena answers, it may on occasions provide incorrect responses. Please confirm any data provided with the related suppliers or authors. We do not provide medical advice, if you search for medical information you must always consult a medical professional before acting on any information provided.

Your questions, but not your email details will be shared with OpenAI and retained for 30 days in accordance with their privacy principles.

Please do not ask questions that use sensitive or confidential information.

Read the full Terms & Conditions.