From a new trigonal cadmium hexacyanoferrate to a Cd Prussian Blue analogue: single‐crystal to single‐crystal transformation and C2H2/CO2 separation capability.

A newly synthesized coordination polymer, [Cd(DMSO)(H2O)]3[Fe(CN)6]2 (CdHCF‐T), based on Cd2+ and Fe(CN)63− ions was prepared in a DMSO/H2O mixed solution and crystalized in the trigonal space group P‐31c. This novel 3D structure presented an interesting single‐crystal to single‐crystal transformation when the coordinated DMSO molecules were replaced by H2O, forming a well‐known Cd Prussian Blue analogue (Cd‐PBA). This occurrence is a rare phenomenon in transition metal hexacyanometallates and may provide a new strategy for obtaining new structures and overcoming the difficulty of growing single crystals of Prussian Blue analogues. Subsequent gas sorption and separation investigations based on the obtained Cd‐PBA were also carried out to evaluate its C2H2/CO2 separation capability. [ABSTRACT FROM AUTHOR]