Molecular Intercalation of Ammonia into Zirconium Disulfide

The intercalation and deintercalation of NH3 into ZrS2 has been investigated by evolved gas analysis, thermogravimetric analysis, differential scanning calorimetry, vapor pressure measurements, SQID magnetometry, and X-ray powder diffraction. Ammonia intercalation of ZrS2, in contrast to other transition metal disulfides (TS2), is predominately a molecular insertion reaction. Only a small amount of NH+4 (<1%) is present in the intercalate, which may be required for intercalation to occur. The small degree of charge transfer can be understood qualitatively within the rigid-band model. The equilibrium intercalate, (NH3)0.92ZrS2, can be indexed to a 3R, stage-1 structure having an occupied layer expansion (3.17 ?) in good agreement with other NH3–TS2 intercalation compounds. The guest–guest and guest–host interactions that stabilize the intercalate apparently involve H2N–H···NH3 and H2N–H···S hydrogen bonding, respectively. Based on this study, ammoniated ZrS2 offers an excellent model system for probing the structure and properties of molecular guest species in lamellar materials.