THE LAYERED BORATES BA3M(BO3)3 (M=DY, HO, Y, ER, TM, YB, LU, AND SC)

A new family of borates of formulation Ba3M(BO3)3 (M = Dy, Ho, Y, Er, Tm, Yb, Lu, and Sc) has been synthesized. The structure of the Sc deri vative has been determined by single-crystal X-ray methods. It crystal lizes in space group P6(3)cm with six formula units in a cell of dimen sions a = 9.227(2), c = 17.135(3) angstrom, and V = 1227.2(5) angstrom 3. The structure contains layers of triangular planar BO3 groups that are interleaved by 9-coordinate Ba atoms and 6-coordinate Sc atoms. An alysis of powder X-ray diffraction data indicates that the analogues c ontaining the M atoms listed above are isostructural to the Sc derivat ive. Analysis of photoluminescence and powder X-ray data for the solid solution Ba3Y1-xEux(BO3)3 reveals the maximum size of the M atom that can be incorporated into the structure. Thermal and melting character istics for each of the M derivatives are also described.