The effects of substitutions M on the formation, structure and magnetic properties of Sm2Fe15M2C2 (M = V, Cr, Ti, Nb, Zr, Mn and Mo) compounds have been systematically studied using XRD, magnetic and Mossbauer measurements. It has been found that V, Cr, Ti, Nb and Zr can help to form the 2 : 17 carbides, with a certain amount of MC (TiC, NbC or ZrC) carbides present in the Ti, Nb or Zr substituted samples, whereas Mn and Mo cannot help to form the 2: 17 carbides. Magnetic measurements reveal that Cr and Nb substituted carbides have a strong c-axis magnetocrystalline anisotropy with anisotropy fields of 93.5 kOe for M = Cr and 72.5 kOe for M = Nb. Mossbauer studies reveal that Cr occupies mainly the 6c and 18h sites whereas Nb occupies only the 18f site. (C) 1998 Elsevier Science B.V. All rights reserved.