Department of Crystallography, Saint-Petersburg State University, St. Petersburg, University emb. 7/9, 199034, Russia.
Inorg Chem. 2013 Apr 15;52(8):4729-35. doi: 10.1021/ic400341q. Epub 2013 Mar 27.
Six different dichromate-based uranyl compounds were obtained. Their structures belong to four principally different but related structure types with different dimensionality of basic structural units. The units in Cs2(UO2)(Cr2O7)(NO3)2 (1) and (C6H11N2)2(UO2)(Cr2O7)2(H2O) (2) are unique, and these are the first “pure” uranyl-dichromates known to date. The compounds Rb2(UO2)(CrO4)(Cr2O7) (3), (C2NH8)2(UO2)(CrO4)(Cr2O7) (4), (C2NH8)2(UO2)(CrO4)2(Cr2O7)(H2O)2 (5), and (C3NH10)2(UO2)(CrO4)2(Cr2O7)(H2O)2 (6) are novel representatives of a rather small group of inorganic compounds containing both isolated CrO4 tetrahedra and dichromate Cr2O7 groups. The structures of 5 and 6 contain compositionally identical but topologically different ∞(2)(UO2)(CrO4)2(Cr2O7) sheets (thus corresponding to different geometrical isomers), which have not been reported previously in inorganic compounds. All novel phases have been prepared with an excess of CrO3. “Pure” dichromates are formed at pH < 1.5 and with prior hydrothermal treatment of uranyl-chromate solution, whereas mixed chromate-dichromates are formed at higher pH > 2 values.
合成了六种不同的重铬酸铀酰化合物。它们的结构属于四种主要不同但相关的结构类型，具有不同维度的基本结构单元。Cs2(UO2)(Cr2O7)(NO3)2 (1) 和 (C6H11N2)2(UO2)(Cr2O7)2(H2O) (2) 中的单元是独特的，这是迄今为止已知的第一批“纯”重铬酸铀酰化合物。化合物 Rb2(UO2)(CrO4)(Cr2O7) (3)、(C2NH8)2(UO2)(CrO4)(Cr2O7) (4)、(C2NH8)2(UO2)(CrO4)2(Cr2O7)(H2O)2 (5) 和 (C3NH10)2(UO2)(CrO4)2(Cr2O7)(H2O)2 (6) 是含有孤立的 CrO4 四面体和重铬酸根 Cr2O7 基团的无机化合物的一个相当小的群体的新型代表。5 和 6 的结构包含组成相同但拓扑不同的 ∞(2)(UO2)(CrO4)2(Cr2O7) 片层（因此对应于不同的几何异构体），这在无机化合物中以前没有报道过。所有新型相都是在 CrO3 过量的情况下制备的。“纯”重铬酸盐在 pH < 1.5 和对铀铬酸盐溶液进行预先水热处理的条件下形成，而在 pH > 2 的较高值下形成混合的铬酸盐-重铬酸盐。
