CRYSTAL-STRUCTURE OF 3R-TA1.08S2

Single crystal of nonstoichiometric Ta1+xS2 with 3R-type structure has been obtained by chemical vapor transport method with NH4CI as transp ort agent. Single crystal of 3R-T1+xS2 grew as thin platelet with meta llic luster. The X-ray Laue photograph has shown that the sample obtai ned has trigonal symmetry with (3) over bar ml Laue group. The structu re has been refined with 3R-type model with R3m space group. The latti ce constants refined are a=3.3169(3), c=18.0141(13)Angstrom and cia is 3x1.810. It has been found that a small excess of Ta atom (x=0.08(1)) is statistically distributed in the interstitial site located between TaS2 sandwiches of 3R-TaS2,. (C) 1998 Elsevier Science S.A.