To deepen the study on heptacoordinate transition metal coordination complexes, a novel seven-coordinated coordination compound [Cd(SCZ)(3)center dot H2O](HTNR)(2)(H2O)(2) (1, SCZ = semicarbazide, H2TNR = styphnic acid) was synthesized and characterized by elemental analysis and FTIR spectroscopy. Single-crystal X-ray diffraction analysis revealed that 1 crystallizes in the triclinic space group P-1. The thermal decomposition mechanism of 1 was studied by differential scanning calorimetry (DSC). The non-isothermal kinetics parameters were calculated by the Kissinger'smethod and Ozawa-Doyle's method, respectively. Sensitivity tests revealed that 1 is insensitive to mechanical stimuli. The heat of combustion was measured by oxygen bomb calorimetry and the enthalpy of formation was calculated.