We have prepared 14 new AA'BB'O-6 perovskites which possess a rock salt ordering of the B-site cations and a layered ordering of the A-site cations. The compositions obtained are NaLnMnWO(6); (Ln = Ce, Pr, Sm, Gd. Dy, and Ho) and NaLnMgWO(6) (Ln = Ce. Pr, Sm, Eu, Gd, Tb, Dy, and Ho). The samples were structurally characterized by powder X-ray diffraction which has revealed metrically tetragonal lattice parameters for compositions with Ln = Ce. Pr and monoclinic symmetry for compositions with smaller lanthanides. Magnetic susceptibility vs. temperature measurements have found that all six NaLnMnWO(6) compounds undergo anti ferromagnetic ordering at temperatures between 10 and 13 K. Several compounds show signs of a second magnetic phase transition. One sample, NaPrMnWO6, appears to pass through at least three magnetic phase transitions within a narrow temperature range. All eight NaLnMgWO(6) compounds remain paramagnetic down to 2 K revealing that the ordering of the Ln(3+) cations in the NaLnMnWO(6) compounds is induced by the ordering of the Mn2+ sub-lattice. (C) 2009 Elsevier Inc. All rights reserved.