Modulated phases of LiTISO_4

Creators Kasano Hironobu

Creators Tsuchiyama Shirou

Creators Kawamura Yukihiko

Creators Mashiyama Hiroyuki

The structurally modulated phases in LiTlSO_4 single crystal are investigated by means of X-ray diffraction. The crystal structure of Phase I in LiTlSO_4 was decided to be isomorphous to that of Phase I (normal phase, space group Pmcn, Z = 4) in LiRbSO_4 and LiNH_4SO_4 by X-ray structural analysis at 320 K. It was found that the satellite reflections with the modulation wavenumber q ~ 0･3a^* appeared in Phase II'(298-267 K) on a cooling run. In Phases II(267-250 K) and III (below 250 K), the modulation wavenumbers were assigned as q = 1/4a^* and q = 1/6a^* + 1/2b^*, respectively. The unit cell volumes of Phases II and III were four times and six times larger than that of Phase I, respectively. It was also found that Phase II did not appear on a heating run from Phase III. The ratio b/a of the basic unit cell size was 1･732 in Phase III as if it were a hexagonal system.

[ISSN]0015-0193

[NCID]AA00644949

info:doi/10.1080/00150199808015029

[isVersionOf] [URI]http://www.tandf.co.uk/journals/titles/00150193.asp