Hydrothermal Synthesis of Sodium Lithium Titanates and Their Crystal Structures

Abstract

New crystals, Na₂Li₂Ti₆O₁₄, Li₂Na_4-2Ti₂O₇, and Li₂Na_4-2Ti₆O₁₄ were synthesized by the hydrothermal reaction of titanium dioxide with sodium hydroxide and lithium hydroxide. The process of formation and the region of synthesis were discussed; and their crystal structures were determined.
Na₂Li₂Ti₆O₁₄ is isomorphous with K₂Li₂Ti₆O₁₄ and orthorhombic, with following cell dimensions: a= 16.38 Å, b=5.76 Å, c= 11.30 Å and Z=4. LixNa₂_Ti30, is also isomorphous with Na₂Ti307 and monoclinic, with following cell dimensions: a=8.55 Å, b=3.78 Å, c=9.11 Å, 8= 101.5° and Z= 2.
Li₂Na_4-2Ti₆O₁₄ is orthorhombic, with space group P21nzn and with following unit cell dimensions: a=37.28 Å, b=9.32 Å, c=2.90 Å, Z=4. The structure of this crystal is outlined below: six octahedra of TiO, are joined by edges, lengthening zigzag in the direction of b-axis and form layers. A unit cell is composed of four layers which are at right angles to a-axis; and among these layers alkali-metal atoms are located.