The crystal structures of the La analogs have previously been described in detail, 14 so we will just provide general details and pay more attention to the peculiarities and differences along the lanthanide row. The crystal structures of all compounds consist of finite numbers of the SrPtSb-type building blocksfused Ln-centered Ni6Si6 hexagonal prisms forming equilateral triangular assemblies or multicentered polyanionic clusters 69 extending along the c axis. The size of the prism edge is equal to the c parameter. Since all structures are homologous, the example with n = 6 will be taken for the illustrations and comparisons (Figure ). Representatives with n = 4-6 have been found