Year: 2026
Type: article
Abstract: ABSTRACT Synthesis of Sr 12 Al 14 O 33 , an isostructural compound to the mineral mayenite (Ca 12 Al 14 O 33 ), was explored through polymeric steric entrapment using Sr(NO 3 ) 2 and/or SrCl 2 6H 2 O as the Sr source. When Sr(NO 3 ) 2 was used as the Sr source, the Sr 12 Al 14 O 33 structure was not formed. When SrCl 2 6H 2 O was used as the Sr source and fired at 1075 for 22 h, a four‐phase mixture with Sr 12 Al 14 O 32 Cl 2 as the majority phase, was achieved suggesting that the larger Cl − anion is needed to template the cage framework structure. However, when firing for 48 h at 1075, the amount of Sr 12 Al 14 O 32 Cl 2 decreased, suggesting the phase is metastable or the phase equilibrium has not been reached. When using a mixture of (12 – x )Sr(NO 3 ) 2 : x SrCl 2 6H 2 O: Al(NO 3 ) 3 9H 2 O where x = 1 and firing at 900 or 1075 only Sr 3 Al 2 O 6 and SrAl 2 O 4 formed, however, with higher amounts of SrCl 2 6H 2 O, Sr 3 Al 2 O 5 Cl 2 appeared along with Sr 3 Al 2 O 6 and SrAl 2 O 4 and Sr 12 Al 14 O 32 Cl 2 was not detected. Further evidence to support the instability of the Sr 12 Al 14 O 32 Cl 2 compound can be seen in how, in samples stored at ambient conditions for longer amounts of time, SrCO 3 started to form and the amount of SrAl 2 O 4 increased, while Sr 12 Al 14 O 32 Cl 2 and Sr 3 Al 2 O 5 Cl 2 both decreased. In situ X‐ray diffraction data are presented showing a complicated pathway when using SrCl 2 6H 2 O and Al(NO 3 ) 3 9H 2 O precursors in a 12:14 ratio. Upon heating Sr 3 Al 2 O 5 Cl 2 starts to form above 620 and remains through 1100, only at this highest temperature does a minor amount of Sr 12 Al 14 O 32 Cl 2 begin to form.
DOI: 10.1111/jace.71288
Institution: University of Tennessee at Knoxville
Language: English
Subfield: Inorganic Chemistry
Field: Chemistry
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $4,070
OpenAlex ID: W7220979730