. 2021 Apr 22;125(17):9050–9059. doi: 10.1021/acs.jpcc.1c00356

Table 2. ²⁹Si NMR Peak Intensities of Si Atoms with Varying Numbers of Al Neighbors in the Zeolite Lattice and the Framework Al Content, c(FAl), Derived Thereof.

	I²/I³/I⁴^a²⁹Si NMR	Si/Al^b	I²/I³/I⁴^c	c(FAl)^d (mmol/g)
USY	13/35/47	5.4	16/31/37	2.6
AHFSY	17/53/30	4.6	17/49/24	3.4

Ratio of NMR intensities Iⁿ (%) of Qⁿ silicon atoms with Si(OSi)_4–n(OAl)_n coordination (I¹ = 100 – I² – I³ – I⁴).

Calculated from Si/Al = ∑Iⁿ/∑nIⁿ.⁴¹

For random Al distribution in lattice without Al–O–Al pairs and Al/Si ratio p: Inline graphic .

From Si/Al, assuming u.c. composition Si_192–nAl_nO₃₈₄H_n.

Table 2. 29Si NMR Peak Intensities of Si Atoms with Varying Numbers of Al Neighbors in the Zeolite Lattice and the Framework Al Content, c(FAl), Derived Thereof.