Synthesis and Characterisation of 5, 5'‐Bistetrazolate Salts with Alkali Metal, Ammonium and Imidazolium Cations

We report on the synthesis and characterisation of the alkali metal 5, 5'‐bistetrazolate (BT 2– ) salts Li 2 BT ( 1 ), Na 2 BT ( 2 ), K 2 BT ( 3 ), Rb 2 BT ( 4 ) and Cs 2 BT ( 5 ) as well as the mono ammonium ( 9 ) and the mono ( 10 ) and bis(1‐ethyl‐3‐methylimidazolium) ( 11 ) salts of 5, 5'‐bistetrazole. The crystal structures of the hydrates of the alkali metal salts ( 1h – 4h ) and hydrate free ( 9 ) to ( 11 ) are presented. Additionally we present structures of the monocaesium 5, 5'‐bistetrazolate ( 6 ) and alternative modifications of the known salts barium ( 7h ) and diammonium ( 8 ) 5, 5'‐bistetrazolate. Among the presented compounds are the first reversibly melting 5, 5'‐bistetrazolate salts ( 10 , 11 ) and also the first ionic liquid on the basis of 5, 5'‐bistetrazole ( 11 ). All substances were investigated by NMR and IR spectroscopy, elemental analysis and combined TGA/DSC measurements. Corresponding to our main motive, the evaluation of the coordination behaviour of 5, 5'‐bistetrazole, we give a short summary of the metal 5, 5'‐bistetrazole salts structurally characterised so far.