# New Compounds In3Ti2AO10, In6Ti6BO22, And Their Solid Solutions (A: Al, Cr, Mn, Fe, Or Ga; B: Mg, Mn, Co, Ni, Cu, Or Zn): Synthesis And Crystal Structures

Published 1999 · Computer Science

Abstract New compounds, In 3 Ti 2 A O 10 ( A : Al, Cr, Mn, Fe, or Ga) and In 6 Ti 6 B O 22 ( B : Mg, Mn, Co, Ni, Cu, or Zn) were synthesized at and above 1000°C in air through solid-state reactions among the constituent cation oxide powders. They are isostructural with the monoclinic and/or orthorhombic In 3 Ti 2 FeO 10 having a pyrochlore-related crystal structure with a commensurate or incommensurate modulated structure. The high-temperature phase is orthorhombic, and the low-temperature phase is monoclinic. The lattice constants of In 3 Ti 2 A O 10 are as follows: In 3 Ti 2 AlO 10 (1200°C): a (A)=5.833(2), b (A)=3.371(2), and c (A)=12.060(6); In 3 Ti 2 AlO 10 (1100°C): a (A)=5.8368(7), b (A)=3.3721(4), c (A)=6.3402(8), and β (°)=107.87(1); In 3 Ti 2 CrO 10 (1200°C): a (A)=5.9246(8), b (A)=3.3562(5), c (A)=6.3546(9), and β(°)=108.10(1); In 3 Ti 2 GaO 10 (1200°C): a (A)=5.861(2), b (A)=3.385(1), and c (A)=12.094(4); In 3 Ti 2 GaO 10 (1000°C): a (A)=5.8742(9), b (A)=3.3828(5), c (A)=6.353(1), and β(°)=107.87(1). In 3 Ti 2 AlO 10 and In 3 Ti 2 GaO 10 are polymorphic. The lattice constants of In 6 Ti 6 B O 22 are as follows: In 6 Ti 6 MgO 22 (1200°C): a (A)=5.9236(7), b (A)=3.3862(4), c (A)=6.3609(7), and β(°)=108.15(1); In 6 Ti 6 MnO 22 (1200°C): a (A)=5.9361(9), b (A)=3.4031(5), c (A)=6.3435(10), and β(°)=108.26(1); In 6 Ti 6 CoO 22 (1200°C): a (A)=5.9243(5), b (A)=3.3841(3), c (A)=6.3495(6), and β(°)=108.18(1); In 6 Ti 6 NiO 22 (1200°C): a (A)=5.9191(6), b (A)=3.3729(3), c (A)=6.3568(6), and β(°)=108.13(1); In 6 Ti 6 CuO 22 (1000°C): a (A)=5.916(2), b (A)=3.379(1), and c (A)=12.029(4); In 6 Ti 6 ZnO 22 (1200°C): a (A)=5.9223(6), b (A)=3.3830(3), c (A)=6.3576(6), and β(°)=108.16(1). In 6 Ti 6 B O 22 ( B : Mg, Mn, Co, Ni, or Zn) are monoclinic and In 6 Ti 6 CuO 22 is orthorhombic. Solid solutions were synthesized in between In 3 Ti 2 A O 10 ( A : Al, Cr, Mn, Fe, or Ga) and In 6 Ti 6 B O 22 ( B : Mg, Mn, Co, Ni, Cu or Zn), and their lattice constants were determined. Temperature in the parenthesis means synthesis temperature, and all the lattice constants were measured at room temperature. The relationship between the unit cells of In 3 Ti 2 A O 10 , In 6 Ti 6 B O 22 , their solid solutions, and the constituent cation elements of A and B are discussed in terms of their tendency for site preference.