STRUCTURE AND PHYSICAL-PROPERTIES OF YSE1.83

YSe1.83 was synthesized by vapor transport technique and its crystal s tructure was determined. The structure was isostructure of LaTe2-x, wh ich was layered structure consisting of two-atom thick layers of YSe w ith distorted NaCl-type structure and one-atom thick layer of Se. The substructure of YSe1.83 was tetragonal with space group of P4/nmm and a=4.011(2) and c=8.261(3) Angstrom with final R/R(w)=6.4/6.9%. The sup erstructure with a(super)=2a, b(super)=6b and c(super)=2c was found. T he measurements of electronic and magnetic properties of this compound indicate that it is an electronic insulator and diamagnet.