Fresnoite: Unusal Titanium Coordination

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Science  09 Jun 1967:
Vol. 156, Issue 3780, pp. 1361-1362
DOI: 10.1126/science.156.3780.1361


The crystal structure of fresnoite, Ba2(TiO)[Si2O7], consists of [Si2O7]6- double groups and titanium-centered square pyramids linked to form flat sheets. Intercalated between these sheets are Ba2+ ions in highly distorted pentagonal antiprisms. The structure of fresnoite is related to that of melilite, (Ca,Na)2(Mg,Al[Si27].