Citation: Sokolova, E.; Hawthorne, F. C.; Abdu, Y. A. (2013). From structure topology to chemical composition. XV. Titanium silicates: revision of the crystal structure and chemical formula of schullerite, Na2Ba2Mg2Ti2(Si2O7)2O2F2, from the Eifel volcanic region, Germany. The Canadian Mineralogist, 51, pp. 715-772.