NEW ONE-DIMENSIONAL CHANNEL STRUCTURES IN THE REDUCED Li-Ti-O SYSTEM. By J. Akimoto*, Y. Gotoh, and Y. Oosawa, National Institute of Materials and Chemical Research, Higashi, Tsukuba, Ibaraki 305, Japan.

The investigation of the reduced Li-Ti-O system has allowed new mixed-valence Ti³⁺/Ti⁴⁺ compounds, LiTi²O⁴ and LiTi₄O₈, to be isolated. Single crystals of these compounds were synthesized by a reaction of lithium metal and titanium dioxide at 1473 K in sealed iron vessels. The crystal structures were determined by single-crystal X-ray diffraction method.

The framework of these compounds is built up from double-rutile-type TiO₆ chains which are connected to each other by corner sharing. LiTi₂O₄ has the orthorhombic ramsdellite-type structure, and is a high-temperature form of the spinel-type LiTi₂O₄. LiTi₄O₈ is an intergrowth phase of rutile and ramsdellite, which consists of [1x1] and [1x2]-type tunnel structures. Lithium atoms are occupied in the ramsdellite-type tunnel space in both compounds. The crystal data of these compounds are given in the following table:

LiTi₂O₄ orthorhombic Pbnm

a = 5.0356(6), b = 9.6377(8), c = 2.9484(7) Å

LiTi₄O₈ monoclinic C2/m

a = 14.1198(11), b = 2.9486(11), c = 4.9373(13) Å

[[beta]] = 92.693(14)deg.