The BaAl_4 structure and its derivatives from the R-Zn-Ga systems

摘要

Seven new ternary RZn_(1+x)Ga_(3-x) (R = Ce, Pr, Nd, Sm, Ho and Er) and Ce_5Zn_2Ga_(17) phases are synthesized for the first time. Their crystal structures are solved on basis of X-ray powder diffraction data. The above mentioned compounds belong to the BaAl_4 (space group I4/mmm) and Rb_5Hg_(19) (space group I4/m) structure types. Details of the structure of the Ce_5Zn_2Ga_(17) compound and relationship with RZn_(2-x)Ga_(2+x) (BaAl_4 type) and R_3Zn_(8-x)Ga_(3+x) (La_3Al_(11) type) are briefly discussed.