Structural Characterization of the Engineered Scavenger Compound, H-Li2Ti3O7

✍ Scribed by P. Bordet; C. Bougerol Chaillout; I.E. Grey; J.L. Hodeau; O. Isnard

• Publisher: Elsevier Science
• Year: 2000
• Tongue: English
• Weight: 405 KB
• Volume: 152
• Category: Article
• ISSN: 0022-4596
• DOI: 10.1006/jssc.2000.8729

✦ Synopsis

The so-called H phase in the system Li 2 O+TiO 2 was prepared from niobia-doped R-Li 2 Ti 3 O 7 (ramsdellite form) by reheating the quenched metastable R phase to 1000 K. The phase was characterized using transmission electron microscopy (TEM), powder X-ray di4raction (XRD), and powder neutron di4raction (ND). It has trigonal symmetry, space group R3 c, with hexagonal cell parameters a ‫؍‬ 5.0744(1) A s and c ‫؍‬ 69.9405(3) A > at 303 K. The unit cell composition is Li 28.5 Ti 36.5 Nb 1.1 O 90 . Highresolution TEM images were used to establish a starting model for the structure, which was re5ned by the Rietveld method using ND data collected at 1.5 K, to R wp ‫؍‬ 5.8%, R B ‫؍‬ 2.0% (350 re6ections). The structure comprises an ordered intergrowth, parallel to (001) of blocks of corundum-type [Ti 2 O 3 ] 2؉ and LiNbO 3 -type structures. The Li atoms in the centre of the LiNbO 3 -type blocks have triangular coordination as in paraelectric LiNbO 3 . The e4ect of temperature on the structure was studied by Rietveld re5nement of XRD data sets collected between 100 and 1173 K. The relationship to the structure of the 546