A chromium-incorporated all-inorganic polyoxoniobate framework material: Good chemical stability and selective ion exchange capability

An all-inorganic three-dimensional (3D) polyoxoniobate (PONb) framework, Na6K4[(Nb6O19)CrIII(H2O)2]2·38H2O (1) has been synthesized via the hydrothermal method. The fundamental building unit of [(Nb6O19)CrIII(H2O)2]210− is connected by K+ ions, forming a 3D framework structure with channels along the b-axis. Compound 1 exhibits good thermal stability, and selectively absorbs Co2+ ions while excluding Ni2+ ions from acetonitrile solutions, PXRD analysis confirms that its framework remains intact after adsorption, indicating its potential as an effective ion-exchange material.