CRYSTAL-STRUCTURE AND MAGNETIC-PROPERTIES OF CEV2AL20 AND CECR2AL20

The crystal structures of the compounds CeV2Al20 and CeCr2Al20 have be en studied by time-of-flight neutron diffraction at room temperature. These compounds have the cubic ZrZn22 type of structure characterised by a single rare earth site and four non-rare earth sites. The neutron diffraction data show that these compounds are true ternary compounds in which the Ce atom occupies exclusively only one of these sites. Fr om magnetic measurements it is derived that Ce is tetravalent. (C) 199 8 Elsevier Science S.A.