  Fluoridoargentates(II) represent a fascinating class of silver(II) compounds
that exhibit structural and magnetic similarities to cuprate superconductors.
However, their synthesis is challenging, leaving their properties largely
unexplored. In this study, mechanochemistry is introduced as a new technique
for the synthesis of fluoridoargentates(II), which avoids the use of anhydrous
HF or heating, and employs simple equipment. Furthermore, by ball milling of
commercially available precursors, AgF and AgF2, we obtained the first two
examples of binary mixed-valent silver(I,II) phases, AgI2AgIIF4 and AgIAgIIF3.
While the AgI2AgIIF4 phase was obtained at room temperature, the AgIAgIIF3
phase is metastable and required milling under cryogenic conditions. Using
synchrotron powder X-ray diffraction, it was found that AgI2AgIIF4 crystallizes
in the P21/c space group and is isostructural to beta-K2AgF4. Here,
double-bridged [AgF6]4- octahedra form chains that propagate along the
a-crystallographic direction, giving a quasi-1D canted antiferromagnetic
character, as shown by magnetic susceptibility. The AgIAgIIF phase adopts the
P-1 space group, is isostructural to AgCuF3 and shows features of a
one-dimensional antiferromagnet. It is expected that this facile synthetic
approach will enable the expansion of silver(II) chemistry and accelerate the
search for a silver analogue to cuprate superconductors.
