KRS-5 (Thallium Bromo Iodide)
Soft crystal transmitting from mid- to far-infrared
Long-Wave IR Crystal
KRS-5 is a soft infrared-transmitting crystal offering extremely broad transmission from the mid- to far-infrared. It is primarily used in FTIR spectroscopy and specialised IR optics. Due to its toxicity and mechanical softness, KRS-5 requires careful handling and encapsulation.
Is this material right for your application?
Use When:
Avoid When:
Consider Alternatives:
Extremely broad mid- to far-IR transmission is required
FTIR spectroscopy spans wide wavelength ranges
Optical flexibility outweighs mechanical strength
Toxic material handling protocols are in place
Components can be encapsulated
Toxic materials cannot be safely handled
Mechanical strength or hardness is required
Environmental exposure is unavoidable
Regulatory constraints limit material choice
KRS-6 – improved durability
ZnSe – safer handling and better robustness
Germanium (Ge) – LWIR optics without toxicity
Key Properties
Optical
Extremely broad mid- to far-IR transmission
High refractive index
Mechanical
Very soft material
Environmental
Toxic
Requires encapsulation
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Frequently asked questions about Barium Fluoride specifications and use-cases
FAQ
Q1. What wavelength range is KRS-5 used for?
KRS-5 transmits from ~0.6 µm to ~40 µm.
Q2. Is KRS-5 suitable for infrared optics?
Yes. It is commonly used for IR spectroscopy windows and components.
Q3. Is KRS-5 hygroscopic?
Yes. KRS-5 is hygroscopic and must be protected from moisture.
Q4. What are common alternatives to KRS-5?
KRS-6, ZnSe, and CsI.
Very soft material and easily scratched
Contains thallium; controlled handling is required
Not suitable for humid or harsh environments