EVIDENCE FOR THE FIRST MISFIT LAYER OXIDE TL-0.41(SR0.9O)(1.12)COO2

A misfit layer oxide Tl-0.41(Sr0.9O)(1.12)CoO2 has been synthesized, a nd its structural model established by ED and HREM. The cell parameter s of the two subsystems have been refined from XRPD data. The subsyste m S-1 (a = 4.9498(5) Angstrom, b(1) = 5.0222(6) Angstrom, c = 11.658(1 ) Angstrom, beta = 97.755(7)degrees) characterizes the strontium-defic ient rock-salt layers [(Sr(0.9)rectangle 0.1)O](infinity), whereas the subsystem S-2 (a = 4.9498(5) Angstrom, b(2) = 2.807(2) Angstrom, c = 11.656(1) Angstrom, beta = 97.755(7)degrees) corresponds to the octahe dral [CoO2](infinity) layers that exhibit the CdI2 structure. The thal lium atoms are located between the two kinds of layers, with a distord ed tetrahedral coordination, ensuring the cohesion of the structure.