Synthesis and crystal structure of [UO2CrO4(C5NH5COO)2(H2O)]·2H2O

Crystals of UO2CrO4(C5NH5COO)2(H2O)] · 2H2O are synthesized and their structure is studied by X-ray diffraction. The compound crystallizes in the triclinic crystal system. The unit cell parameters are as follows: a = 7.0834(10) Å, b = 10.6358(14) Å, c = 12.9539(17) Å, α = 75.096(2)°, β = 74.490(2)°, and γ = 80.657(2)°; V = 904.1(2) Å3, space group P\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ \bar 1 $$\end{document}, Z = 2, and R = 0.026. The structure is built of [UO2CrO4(C5NH5COO)2(H2O)]2 centrosymmetric dimers, which are linked into a framework by a system of hydrogen bonds involving inner-sphere and outer-sphere water molecules. The coordination number of the U(VI) atom is seven, and the coordination polyhedron is a pentagonal bipyramid with the oxygen atoms of the uranyl group, two chromate groups, two molecules of isonicotinic acid, and a water molecule at the vertices. The crystal chemical formula of the [UO2CrO4(C5NH5COO)2(H2O)]2 dimer is represented as AB2M31, where AB2M31, where A = UO22+, B2 = CrO42−, and M1 = = C5NH4COOH and H2O.