Isopropylammonium Layered Uranyl Chromates: Syntheses and Crystal Structures of [(CH₃)₂CHNH₃]₃[(UO₂)₃(CrO₄)₂O(OH)₃] and[(CH₃)₂CHNH₃]₂[(UO₂)₂(CrO₄)₃(H₂O)]

Abstract

Abstract Two novel isopropylamine‐templated uranyl chromates, [(CH 3 ) 2 CHNH 3 ] 3 [(UO 2 ) 3 (CrO 4 ) 2 O(OH) 3 ] ( 1 ) and [(CH 3 ) 2 CHNH 3 ] 2 [(UO 2 ) 2 (CrO 4 ) 3 (H 2 O)] ( 2 ) were prepared by hydrothermal method at 100 °C. The compounds were characterized by electron microprobe analysis and X‐ray diffraction crystal structure analysis [ 1 : trigonal, P 31 m , a = 9.646(4), c = 8.469(4) Å, V = 682.4(5) Å 3 ; 2 : monoclinic, P 2 1 / c , a = 11.309(3), b = 11.465(3), c = 17.055(5) Å, β = 99.150(6)°, V = 2183.2(11) Å 3 ]. The structure of 1 is based upon trimers of uranyl bipyramids interlinked by CrO 4 tetrahedra to form [(UO 2 ) 3 (CrO 4 ) 2 O(OH) 3 ] 3– layers, whereas, in the structure of 2 , UO 7 and UO 6 (H 2 O) pentagonal bipyramids are linked through CrO 4 tetrahedra into the [(UO 2 ) 2 (CrO 4 ) 3 (H 2 O)] 2– layers. The structures show many similarities to related uranyl selenate compounds, thus providing additional data on similarities and differences between uranyl sulfates, chromates, selenates, and molybdates.