Host-guest structural architectures in hydrous alkaline (Li, K) uranyl chromates and dichromates

•Single crystals of new (Cr2O7)2- and/or (CrO4)2- containing uranyl compounds with K and Li were prepared by two various synthesis routes•Uranyl chromate-dichromate compound with K demonstrates unique host-guest structural architecture•Structure can be described as incorporation of [(UO2)(CrO4)4]6- clusters into the K2Cr2O7 matrix that induces modification of the latter•Li uranyl chromate architecture is typical for uranyl oxysalts with [Li2(H2O)5]2+ tetramers guest species

Two new (Cr2O7)2 − and/or (CrO4)2 − containing uranyl compounds with K and Li: [K10(Cr2O7)2(H2O)2]|(UO2)(CrO4)4 | (1) and | Li2(H2O)5 |[(UO2)(CrO4)2] (2) were obtained via two various synthesis routes in the K2Cr2O7–CrO3–(UO2)(NO3)2·6H2O–H2O (1) and LiCl–CrO3–(UO2)(NO3)2·6H2O (2) systems. The key feature of the crystal structure of 1 is the formation of hydrous potassium dichromate [K10(Cr2O7)2(H2O)2]6 + 2D units acting as hosts for guest |(UO2)(CrO4)4 |6 − clusters. (Cr2O7)2 − groups are not bonded via common oxygen atoms to (UO2)2 + in 1 which is the first example of such structural architecture in uranyl oxysalts with tetrahedral TO4 (T = Si4 +, As5 +, P5 +, Cr6 +, etc.) anions. In the structure of 2, UrO5 and CrO4 coordination polyhedra share corners to produce [(UO2)(CrO4)2]2 − layers with | Li2(H2O)5 |2 + tetramers guest species in the interlayer.

Graphical abstractTwo new uranyl chromate-dichromate compounds with K and Li with two different host-guest structural architectures.Figure optionsDownload full-size imageDownload as PowerPoint slide