Abstract:119Sn and 57Fe Mossbauer spectra of franckeite from D;ichang, Guangxi province, have been studied at zoom temperature. The relevant Mossbauer pa- rameters are given. The measured 119Sn spectrum shows that all the tin ions in the sample are Sn0' (no Sn2+ in it).The Sn spectrum consists of two com- ponent spectra, which were assignedto Sn4+ in pseudotetralronal (T layer) and pseudohexagonal (H layer) structures of the mineral, respectively. Both the coordination numbers are six. The Sn4+ in T layer occupies the octahedral site with greater distortion, and thus has a greater QS value. The Sn'*-—S bond has greater ionicity and less covalency.The 57Fe spectrum shows that all the iron ions in the sample are Fe2+ (no Fe3+ in it).The 57Fe spectrum also consists of two component spectra, which were assigned to high-spin Fe2+ (with stranger ionicity) in T layer and low-spin Fe2+ (with stronger cova- lency) in H layer, respectively. The site populations of the Sn4+ and Fe2+ were obtained from percent areas of the component spectra. The positive and ne- gative valency charges in the chemical formula of the sample are 27.99 and 28.02, respectively, which leach a equilibrium of charges. Based on the results of single crystal X-say diffraction, Mossbauer and chemical analyses of this sample, the crystal chemical formula of Dachang franckeite can be written as 〔(Pb0.732Sb3+0.086Sn4+0.083Fe2+0.078Ag0.021) 1.000S]·0.366(Sn4+0.459Sb3+0.440Fe2+0.10)1.000S2]. It is proved that excess opposite electric charges connect the T layer with the H layer.