The orthorhombic polymorph of diammonium trichromate(VI) decaoxide, α–(NH4)2Cr3O10

Casari, Barbara M.; Öberg, Elisabeth; Langer, Vratislav

doi:10.1007/s10870-006-9165-6

Cited by 2 publications

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References 15 publications

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“…These observations can be explained by the fact that Cr 6+ cation is larger than S 6+ and smaller than Se 6+ . It is well-known that the CrO 4 2– ions display the ability to polymerize, which results in the formation of multiple groups such as Cr 2 O 7 2– dimers, Cr 3 O 10 2– trimers, or even Cr 4 O 13 2– tetramers . However, in the majority of uranyl-chromates known to date, chromate ions are not polymerized, which may well be the consequence of the use of A n CrO 4 and A n Cr 2 O 7 , n = 1–2 (A = Na, K, Rb, Cs, Tl, Ca, Mg), as starting reagents in their synthesis.…”

Section: Introductionmentioning

confidence: 99%

Cr(VI) Trioxide as a Starting Material for the Synthesis of Novel Zero-, One-, and Two-Dimensional Uranyl Dichromates and Chromate-Dichromates

et al. 2013

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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)](2–) 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.

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Section: Introductionmentioning

confidence: 99%

Cr(VI) Trioxide as a Starting Material for the Synthesis of Novel Zero-, One-, and Two-Dimensional Uranyl Dichromates and Chromate-Dichromates

et al. 2013

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Effect of solution acidity on the crystallization of polychromates in uranyl-bearing systems: synthesis and crystal structures of Rb₂[(UO₂)(Cr₂O₇)(NO₃)₂] and two new polymorphs of Rb₂Cr₃O₁₀

Nazarchuk

Siidra

Charkin

et al. 2021

Zeitschrift Für Kristallographie - Crystalline Materials

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Three new rubidium polychromates, Rb2[(UO2)(Cr2O7)(NO3)2] (1), γ-Rb2Cr3O10 (2) and δ-Rb2Cr3O10 (3) were prepared by combination of hydrothermal treatment at 220 °C and evaporation of aqueous solutions under ambient conditions. Compound 1 is monoclinic, P 2 1 / c $P{2}_{1}/c$ , a = 13.6542(19), b = 19.698(3), c = 11.6984(17) Å, β = 114.326(2)°, V = 2867.0(7) Å3, R 1 = 0.040; 2 is hexagonal, P 6 3 / m $P{6}_{3}/m$ , a = 11.991(2), c = 12.828(3) Å, γ = 120°, V = 1597.3(5) Å3, R 1 = 0.031; 3 is monoclinic, P 2 1 / n $P{2}_{1}/n$ , a = 7.446(3), b = 18.194(6), c = 7.848(3) Å, β = 99.953(9)°, V = 1047.3(7) Å3, R 1 = 0.037. In the crystal structure of 1, UO8 bipyramids and NO3 groups share edges to form [(UO2)(NO3)2] species which share common corners with dichromate Cr2O7 groups producing novel type of uranyl dichromate chains [(UO2)(Cr2O7)(NO3)2]2−. In the structures of new Rb2Cr3O10 polymorphs, CrO4 tetrahedra share vertices to form Cr3O10 2− species. The trichromate groups are aligned along the 63 screw axis forming channels running in the ab plane in the structure of 2. The Rb cations reside between the channels and in their centers completing the structure. The trichromate anions are linked by the Rb+ cations into a 3D framework in the structure of 3. Effect of solution acidity on the crystallization of polychromates in uranyl-bearing systems is discussed.

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The orthorhombic polymorph of diammonium trichromate(VI) decaoxide, α–(NH4)2Cr3O10

Cited by 2 publications

References 15 publications

Cr(VI) Trioxide as a Starting Material for the Synthesis of Novel Zero-, One-, and Two-Dimensional Uranyl Dichromates and Chromate-Dichromates

Cr(VI) Trioxide as a Starting Material for the Synthesis of Novel Zero-, One-, and Two-Dimensional Uranyl Dichromates and Chromate-Dichromates

Effect of solution acidity on the crystallization of polychromates in uranyl-bearing systems: synthesis and crystal structures of Rb₂[(UO₂)(Cr₂O₇)(NO₃)₂] and two new polymorphs of Rb₂Cr₃O₁₀

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The orthorhombic polymorph of diammonium trichromate(VI) decaoxide, α–(NH4)2Cr3O10

Cited by 2 publications

References 15 publications

Cr(VI) Trioxide as a Starting Material for the Synthesis of Novel Zero-, One-, and Two-Dimensional Uranyl Dichromates and Chromate-Dichromates

Cr(VI) Trioxide as a Starting Material for the Synthesis of Novel Zero-, One-, and Two-Dimensional Uranyl Dichromates and Chromate-Dichromates

Effect of solution acidity on the crystallization of polychromates in uranyl-bearing systems: synthesis and crystal structures of Rb2[(UO2)(Cr2O7)(NO3)2] and two new polymorphs of Rb2Cr3O10

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Effect of solution acidity on the crystallization of polychromates in uranyl-bearing systems: synthesis and crystal structures of Rb₂[(UO₂)(Cr₂O₇)(NO₃)₂] and two new polymorphs of Rb₂Cr₃O₁₀