Crystal structures of two new misfit compounds, [SrGd 0.5 S 1.5 ] 1.16 NbS 2 and [Sr(Fe,Nb) 0.5 S 1.5 ] 1.13 NbS 2 , were determined through the composite approach, i.e., by refining each subpart (Q, H-parts, and the common part) of these composite materials, separately. The Q-part is a three-atom-thick layer, with the NaCl-type structure, where external SrS planes enclose the inner GdS or (Fe,Nb)S plane; the structural difference between these two compounds lies in the central layer within the Q-part: Gd and S atoms are in special positions (octahedral coordination), while Fe and S atoms are statistically distributed on split ( Â 4) positions (tetrahedral coordination) around a central unique site (=special position occupied by Nb). The Hpart is a sandwich of sulfur planes enclosing the inner Nb plane as observed for the structure of the binary compound NbS 2 itself. The Sr-Gd derivative shows a paramagnetic behavior in the whole studied temperature range (2-300 K). On the other hand, antiferromagnetic interactions occur in the Sr-Fe derivative; the complex magnetic behavior of this compound is related to the statistical distribution of Fe atoms which leads to frustration of the magnetic interactions. At room temperature, experimental values obtained from M. ossbauer spectrum correspond to Fe 3+ in tetrahedral sulfur environment: isomer shift d ¼ 0:32 mm s À1 , and quadrupole splitting DE ¼ 0:48 mm s À1 .