Synthesis, Characteristics and Standard Molar Enthalpies of Formation of MZn2HPO4PO4 (M=Na+, K+)

• 来源期刊: 中国化学（英文版）
• 年，卷（期）: 2008,（7）
• 页码范围: 1210-1214
• 页数: 5页
• 语种: 英文

摘要

MZn2HPO4PO4(M=Na+,K+) double salts were synthesized by a solid-state reaction at low temperature and a hydrothermal method, respectively, and characterized by XRD, FT-IR, TG and SEM. Thermochemical study was performed by an isoperibol solution calorimeter. According to Hess's law, a new thermochemical cycle was de-signed. The results show that the obtained products are layered compounds with an isostructure of triclinic system.The decomposition temperatures are 415 and 430℃ by TG, respectively. With the dissolution enthalpies and other standard chemical data, the standard molar formation enthalpies of the MZn2HPO4PO4(M=Na+,K+) were worked out as follows: △fH(○)m[NaZn2HPO4PO4,s]=(-3042.38±0.31) kJ·mol-1 and △fH(○)m[KZn2HPO4PO4,s] = (-3093.46±0.27) kJ·mol-1.