Syntheses and properties of a family of new compounds RE3Sb3Co2O14 (RE=La, Pr, Nd, Sm-Ho) with an ordered pyrochlore structure

La3Sb3Co2O14 crystallizes in a pyrochlore related structure with an ordered distribution of cations, giving rise to two sets of ideal 2D Kagome lattices formed by La3+ or Sb5+ respectively. This rhombohedral pyrochlore is a tolerant structure for stable compounds composed by many light rare-earth and d-transition elements. Substituting Zn2+ or Mg2+ for Co2+ will provide a series of compounds useful for studying magnetic interactions in the rare-earth Kagome lattices.