F. Colombo and E. V. Pannunzio Miner (2009): Synthesis and crystal structure refinement by the Rietveld method of antimony-bearing titanite Ca(Ti0.6Al0.2Sb0.2)OSiO4. Powder Diffraction 24, 221-227.
A synthetic analogue, Ca(Ti0.6Al0.2Sb0.2)OSiO4, of antimony-bearing titanite of a composition similar to that found at St. Marcel-Praborna (Italy) was synthesized using ceramic methods and the crystal structure was refined using the Rietveld method. Unit-cell dimensions (in Å) are a = 7.0184(1), b = 8.797(2), c = 6.5586(1), b = 113.700(1)º. The substitution of 40% Ti by (Al+Sb) in octahedra causes a loss of long-range coherency of the off-centered Ti atoms. The space group of Sb-bearing titanite is A2/a, like other cases of M3+-M5+-doped titanites. This study confirms that titanite with up to 0.2 Sb atom per formula unit can exist, and that the substitution scheme is 2 Ti4+ ↔ Al3+ + Sb5+.
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