Mechanochemistry of fluoride solids: from mechanical activation to mechanically stimulated synthesis

Abstract

This lecture text is focused on the comparatively young field of mechanochemistry of fluoride solids, considering both their mechanical activation and their mechanochemical synthesis. Beside a literature survey, the mechanochemical synthesis of binary fluorides MF2, MF3, of complex fluorides MMgF4, of solid solutions MaxMb1−xF2 or M1−xLnxF2+x (Ln: Y, Eu) and of fluorine-containing coordination polymers is presented. Owing to their interesting potential applications in the field of fluoride ion conductivity or luminescence properties when doped, most of the given examples are alkaline earth metal compounds. A short historical survey, remarks on peculiarities and consequences of mechanical activation as well as the necessary technical equipment for mechanochemical reactions precede the section. Graphic abstract

Mechanochemical Synthesis and Fluoride Ion Conductivity Studies in SrSnF4 Polymorphs

“…It can also be seen that the mechanical activation reduced the preparation temperature from 773 K (solid-state reaction) to 573 K, and furthermore, the later method avoids complex synthesis procedures such as copper tube-based evacuation and heat treatment at higher temperatures. Mechanical milling has been recently found as one of the efficient techniques employed for the preparation of fast fluoride ion-conducting materials. , The present work is attempting to study the influence of mechanical milling and soft annealing toward the crystallizing of SrSnF 4 in two polymorphs. Various reports are known on the development of PbSnF 4 and BaSnF 4 materials in different forms and their applications on room-temperature FIBs. ,, However, the structural and transport details of the isostructural system SrSnF 4 are not known probably due to its low ionic conductivity value in comparison to the other MSnF 4 (M: Pb and Ba) materials.…”

“…Mechanical milling has been recently found as one of the efficient techniques employed for the preparation of fast fluoride ion-conducting materials. 15,16 The present work is attempting to study the influence of mechanical milling and soft annealing toward the crystallizing of SrSnF 4 in two polymorphs. Various reports are known on the development of PbSnF 4 and BaSnF 4 materials in different forms and their applications on room-temperature FIBs.…”