Citation: Tschauner, O.; Kiefer, B.; Liu, H.; Sinogeikin, S.; Somayazulu, M.; Luo, S.-N. (2008). Possible structural polymorphism in Al-bearing magnesiumsilicate post-perovskite Sample: 2X1 Note: atom sites modified after communication with author. American Mineralogist, 93, pp. 533-539.