KRS-5

https://doi.org/10.1351/goldbook.08630
Eutectic (42 %TlBr,58%TlI) mixture of thallium bromide and thallium iodide transparent to infrared radiation used as window in infrared spectroscopy.
Note:
KRS-5 transmits well down to 200 cm−1. It is practically insoluble in water but its refractive index is rather high (approximately 2.35). It is rather plastic and deforms with time, and it is poisonous.
Source:
PAC, 2021, 93, 647. (Glossary of methods and terms used in analytical spectroscopy (IUPAC Recommendations 2019)) on page 752 [Terms] [Paper]
Citation: 'KRS-5' in IUPAC Compendium of Chemical Terminology, 5th ed. International Union of Pure and Applied Chemistry; 2025. Online version 5.0.0, 2025. https://doi.org/10.1351/goldbook.08630 RIS BibTex EndNote
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