Why kBr does not absorbs ir spectra?

Potassium bromide (KBr) does not absorb infrared (IR) spectra because it is a nonpolar ionic compound. Its ionic bonds do not have a permanent dipole moment, which means there are no vibrational modes that can interact with IR radiation. Additionally, KBr has a wide transparency range in the IR spectrum, allowing it to be used as a window material in IR spectroscopy without interfering with the absorption of other substances being analyzed.