Calcium titanosilicate

SPHENE. Thismineral occurs as ayellow, green, gray, or brown calcium titanosilicate, corresponding to formula CaTiSiOj, crystallizing in the monoclinic system. Fracture conchoidal to uneven brittle habit usually wedge-shaped and flattened crystals, also massive and lamellar luster, resinous to adamantine transparent to opaque hardness, 5-5.5 specific gravity. 3.45 3.55... 

As ceramics based on multicomponent oxides, the following systems were taken into consideration calcium titanosilicate [61], strontium bismuth tantalate [62], barium magnesium tantalite [63], sodium cobalt oxide [64], and muUite [65-78]. 

Montmorillonite, silicate, aluminosilicate, titanosilicate, calcium phosphate, zirconium phosphate, metal oxides, and heteropolyacids composites with Nation exhibit in general a modest barrier effect to methanol permeation (F, > 0.1), with a couple of exceptions aCloisite lOA composite [62] with 0.013 < F, < 0.065, and a chitosan-functionalized montmorillonite composite [71] with 0.028 < F < 0.050, in both cases for clay contents between 1 and 10 wt%. 

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