Crystallographic data of new ternary Sm5Ge4-type Gd2Sc3Ce4 and R2Sc3Si4 compounds (R=Sm, Gd-Tm)

Investigations made by powder X-ray diffraction on eight new ternary Gd2Sc3 Ge4 and R2Sc3Si4 compounds (R=Gd-Tm) are reported. The following compounds were observed to crystallize in the orthorhombic Sm5Ge4-type structure (spa ce group Pnma): Gd2Sc3Ge4 (a=0.7211(2) nm, b=1.4050(6) nm, c=0.7453(3) nm), Sm2Sc3Si4 (a=0.7094(1) nm, b=1.3992(4) nm, c=0.7402(2) nm), Gd2Sc3Si4 (a=0 .7092(2) nm, b=1.4012(4) nm, c=0.7412(2) nm), Tb2Sc3Si4 (a=0.7078(1) nm, b= 1.3982(3) nm, c=0.7395(2) nm), Dy2Sc3Si4 (a=0.7060(1) nm, b=1.3951(4) nm, c =0.7380(2) nm), Ho2Sc3Si4 (a=0.7042(1) nm, b=1.3921(4) nm, c=0.7362(2) nm), Er2Sc3Si4 (a=0.7028(1) nm, b=1.3894(4) nm, c=0.7343(2) nm) and Tm2Sc3Si4 ( a=0.7011(2) nm, b=1.3852(5) nm, c=0.7324(2) nm). (C) 1998 Elsevier Science S.A. All rights reserved.