Synthesis and Characterization of Sr12Al14O33

Conference: 2022: 72nd ACA Annual Meeting
Claudia Rawn Poster Author
University of Tennessee, Knoxville
Knoxville TN, TN 
Katherine (Katie) Loughlin Additional Author
University of Tennessee, Knoxville
Knoxville, TN 
Michael Koehler Additional Author
University of Tennessee, Knoxville
Knoxville, TN 
07/31/2022: 5:30 PM - 7:30 PM
Poster Session 
Portland Marriott Downtown Waterfront 
Room: Exhibit Hall 


Ca12Al14O33 has many interesting and potentially exploitable properties that arise from its crystal structure. The compound is known for being a room-temperature inorganic electride, and depending on the processing conditions, it can have near-metallic electrical conductivity. The unit cell is cubic, space group I4 ̅3d (no. 220), with a lattice parameter of ∼12 Å and contains two formula units. The Ca, Al, and majority of the O create a framework of twelve cages per unit cell, within which the remaining two O are occluded. Isostructural compounds with different cation combinations may result in larger cages and enhanced properties. Using wet chemical methods and initially dissolving Al(NO3)3 • 9H2O and SrCl2 • 6H2O in deionized H2O, Sr12Al14O33 has been synthesized, but attempts to eliminate secondary phases have not succeeded. Room temperature and high temperature X-ray diffraction data have been used to track the phase evolution. One consideration based on the synthesis is that Cl-, with a significantly larger ionic radius than O2-, is being occluded; the replacement of the divalent O with monovalent Cl would allow for more cages to be filled. However, the cage occupant is difficult to interrogate due to the low occupancy.