The gas-phase reaction between MoO3-x and H2S in a reducing atmosphere at elevated temperatures (800 degrees to 950 degrees C) has been used to synthesize targe quantities of an almost pure nested inorganic fullerene (IF) phase of MoS2. A uniform IF phase with a relatively narrow size distribution was obtained. The synthesis of Ifs appears to require, in addition to careful control over the growth conditions, a specific turbulent flow regime. The x-ray spectra of the different samples show that, as the average size of the IF decreases, the van der Waals gap along the c axis increases, largely because of the strain involved in folding of the lamella. Large quantities of quite uniform nanotubes were obtained under modified preparation conditions.