“…[13] All compounds were also characterized by chemical analysis, [14][15] and analytical results are presented in Table 1. Analyses indicated that impurities of Ho, Dy, Yb, La, Tm, Er, Pr, Sm, Te, Ca, Mg, Mn, Pb, and Ag were present at levels of between 10 -3 and 10 -4 at.-%.…”