Systematic Study on Crystal Structures in Tetragonal RB₂C₂ (R=Rare Earth) Compounds

Abstract

Detailed crystal structures of the tetragonal RB 2 C 2 (R=La, Ce, Pr, Nd, Tb, Dy, Ho, Er, Tm and Lu) compounds which include the antiferroquadrupolar ordering materials, DyB 2 C 2 and HoB 2 C 2 , have been investigated by neutron powder diffraction technique. RB 2 C 2 are crystallised in the same LaB 2 C 2 type crystal structure with P 4/ m b m symmetry. The structure of the B–C network which consists of non-regular squares and octagons are nearly the same in the system except slight rotation as rare earth atoms become heavier.