K2Na(I3O8)3: a promising mid-infrared birefringent material with two different structures of octaoxotriiodate(V) groups

An alkali metal polyiodate, K 2 Na(I 3 O 8 ) 3 , has been synthesized via a hydrothermal method using phosphoric acid as the reaction medium. The compound features two distinct octaoxotriiodate(V) polyanions, which adopt divergent structural...