کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
1313954 | 1499326 | 2015 | 8 صفحه PDF | دانلود رایگان |

• Structural characterization indicates substantial disorder of anionic lattice.
• 3–4 Times smaller grain size than that of parent AgF and AgCl.
• Surprisingly low melting point and small entropy change at melting.
• 3 Times larger charge carrier density than those of pristine AgF and AgCl.
• However, ionic conductivity lower than that of AgF.
Several types of mixed-anion fluoride–chloride phases of silver(I) (with stoichiometries close to AgF0.5Cl0.5 and AgF0.75Cl0.25) have been synthesized for the first time in reactions between AgF (or AgF2, respectively) and AgCl. The products crystallize in the rock salt unit cell, similarly to the pristine AgF and AgCl phases. The members of the Ag(F1−xClx) series exhibit an almost linear relationship of the cubic cell vector with the composition parameter, x, which indicates that AgF and AgCl form a solid solution with a disordered anionic sublattice. The AgF0.5Cl0.5 phase exhibits quite a low melting point of 307 °C (as compared with 435 °C for AgF and 455 °C for AgCl), and small entropy change at melting, some 10 J (mol K)−1 (as compared to 23.6 J (mol K)−1 for AgF, and 18.1 J (mol K)−1 for AgCl), indicative of high disorder and large absolute entropy of AgF0.5Cl0.5 solid. Despite that, the Ag(F1−xClx) phases show smaller specific electric conductance than the end members of the series, AgCl and AgF. Parent AgF turns out to have rather high specific conductance of 3 × 10−2 mS cm−1 at a room temperature and rather small activation energy for conductivity (29.2 kJ mol−1) which suggest the presence of high concentration of defects and substantial electron doping to the conduction band.
AgF1−xClx phases showing substantial disorder of anionic sublattice have been prepared and characterized for the first time.Figure optionsDownload as PowerPoint slide
Journal: Journal of Fluorine Chemistry - Volume 174, June 2015, Pages 22–29