Ethylenediammonium hexasulfide has been synthesized from ethylenediamine, sulfur, and gaseous H2S in aqueous solution. X-ray investigations on single crystals revealed its structure. The monoclinic unit cell contains eight formula units, the space group is Cc. The sulfur atoms form unbranched zig-zag chains S62- in all-trans-conformation.

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Water-swollen K-and Na- vermiculites in flakes, 1 to 2 mm in size, were equilibrated with aqueous solutions of K+ and Na+ (and Cl-) ions, at 26, 60 and 90 °C. The shape of the isotherms and the types of vermiculites involved revealed the existence of two groups of cation exchange sites corresponding to the alternate interlayer spaces. These two site groups are responsible for two cation exchange reactions. The equivalent fractions of the two groups are equal or unequal, according to the working conditions. Unequal equivalent fractions correspond to a metastable electronic structure of the layers. Complex isotherms are broken up into two simple isotherms. The exchange standard thermodynamic functions were calculated. A structural interpretation was proposed.