Infrared Spectroscopic Characterization of CIT-6 and a Family of *BEA Zeolites

Table 2

Far-IR peaks for CIT-6 and its derivatives. The notations are as follows: w is weak intensity, m is medium intensity, s is strong intensity, and sh is shoulder.

As-made CIT-6	Calcined	Zn CIT-6	High-𝑇 Si *BEA	Low-𝑇 Si *BEA	Aluminum	Pure Si *BEA	Assignment
	640 sh, m		640 w	638 sh, w		642 w	Double-ring modes [14, 15]
614 m	622 m	614 m	622 m	624 w	622 w	622 m
577 m	577 s	576 s	576 s	574 m	569 m	575 s
526 m	528 m	527 m	527 w	526 m	521 w	524 w
	474 s	473 sh, w	475 s	473 sh, s	472 sh, s	474 s	δ (T–O) [14, 15]
466 s	465 s	463 s	466 s	463 s	463 s	461 s
431 s	427 s	429 s	426 s	429 s		423 vs
	374 w		373 sh, w	373 sh, w		373 w	Pore-opening modes [14, 15]
360 w	357 sh, w	362 w	357 sh, w			355 w
			342 sh, w	347 sh, w	350 sh, m	340 w