Using of zeolite LOS for preparation of sulfur pigments

Zeolite losod prepared with tetrabutylammonium hydroxide was applied as matrix for sulfur anion-radicals thermally generated from precursors (elemental sulfur and alkalis or alkaline oligosulfides). We hoped that large los   cages could favor formation and stabilization of big radicals (e.g. red S4-). The products with maintained LOS structure, however, always showed light green or blue coloration (due to S3- and S2- radicals) and bigger radicals never were detected (EPR). It is likely that the sulfur radicals in the products occupy rather eri cages in LOS structure, whereas the large los cages do not accommodate any radicals, because several of them could stay there and subsequently recombine to ordinary oligosulfides. Some reduction of los cage size by means of Cs or K cations resulted in a degradation of LOS structure. Introduction of sulfur compounds already during the losod crystallization disturbed formation of LOS structure.