Thallium Bromoiodide
- KRS-5
KRS-5 (Thallium Bromoiodide) is a versatile infrared optical material prized for its exceptional transmission range from 0.6 µm to 40 µm, covering the visible through far-infrared regions. It is particularly valued for FTIR spectroscopy, thermal imaging, and ATR (attenuated total reflectance) applications due to its wide spectral coverage and mechanical flexibility compared with other IR crystals.
With a moderate refractive index (~2.37 @ 10 µm) and low dispersion, KRS-5 delivers excellent optical performance in broadband IR systems. It is non-hygroscopic, ensuring long-term stability even in humid environments — a major advantage over hygroscopic materials such as NaCl or KBr.
At Global Optics UK, we supply precision-fabricated KRS-5 windows, prisms, and ATR crystals, available uncoated or with custom anti-reflective or protective coatings. Each component is manufactured to stringent optical and dimensional tolerances, making KRS-5 an excellent choice for spectroscopy, gas analysis, and thermal imaging systems that require broad IR coverage and mechanical durability.
Explore Related Optical Materials:
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FAQ
FAQ
Q: What is KRS-5 used for?
A: KRS-5 is commonly used in FTIR spectroscopy, ATR (attenuated total reflection) crystals, long-wave infrared optics, gas analysis windows, prisms, and broadband IR beam paths. Its extremely wide transmission range (0.6–40 µm) makes it suitable for both mid-IR and far-IR systems.
Q: Why is KRS-5 popular for ATR applications?
A: KRS-5 has a high refractive index (~2.37), which produces a strong evanescent field and increases interaction with samples. This makes it highly effective for chemical, biological, and industrial ATR measurements.
Q: Is KRS-5 moisture resistant?
A: Yes. KRS-5 is only slightly hygroscopic and is far more moisture-resistant than materials such as KBr or NaCl. It performs well under normal laboratory conditions.
Q: Is KRS-5 toxic?
A: KRS-5 contains thallium compounds, which are toxic. Finished components are safe to handle when clean and mounted, but the material must not be touched with bare hands or exposed to acids. Gloves should always be worn during cleaning or assembly.
Q: How mechanically durable is KRS-5?
A: KRS-5 is very soft (Mohs ~1) and scratches easily. It should not be cleaned with abrasives or wiped aggressively. Protective mounting is strongly recommended.
Q: Can KRS-5 withstand high temperatures?
A: KRS-5 is stable up to around 200 °C in dry, controlled environments. However, due to its high thermal expansion and softness, it is sensitive to thermal shock and rapid temperature changes.
Q: What is the transmission range of KRS-5?
A: KRS-5 transmits from approximately 0.6 µm to 40 µm, making it one of the broadest infrared window materials available for FTIR, LWIR, and far-IR applications.
Q: Where can I download the datasheet?
A: The full KRS-5 technical datasheet is available here.