To design materials for energy, electronic and ionic mobility are key features. The chemical bonding involving transition metal or rare-earth ions with more electronegative elements is the common thread. Imagining novel compounds and networks by associating at least two anions with different electronegativity in order to create competitive bonds around metallic ions allow us tuning physical and chemical properties and generating new one’s. It represents also a growing challenge in the field of inorganic synthesis routes, the knowledge of motley structures and finally the transport (electronic+ ionic) properties.

In this journey, we will explore the interest to mix fluorine with  less electronegative anions in order to create unusual transport properties ¹. Original synthesis routes involving fluorine and at least one additional anion will be presented and discussed with its diversity. Crystal structures will be analyzed and solved considering anionic order and disorder². Finally the physical and chemical properties will be correlated to the composition and structural features, illustrating the fantastic playground offered by mixing anions in inorganic compounds containing fluorine ^1,2.