Fig. 1: Comparison of crystal structures between (HaaOH)BF4 and (Haa)BF4 at 293 K.

Asymmetric units of a (HaaOH)BF4 and b (Haa)BF4. c Packing view along the c-axis of (HaaOH)BF4.The anions and cations are ordered. The dotted lines represent hydrogen bonding interactions. d Packing view along the c-axis of (Haa)BF4. The anions and cations are orientationally disordered. Parts of hydrogen atoms are omitted for clarity.