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Ilyushin GD. Modeling of self-organization processes in crystal-forming systems: Symmetry and topology code for cluster self-assembly of crystal structures in MT-structures of polyvalent sulfates and phosphates. RUSS J INORG CHEM+ 2015. [DOI: 10.1134/s0036023615140028] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Beiträge zum thermischen Verhalten wasserfreier Phosphate VIII.* Darstellung und Kristallstruktur von Cr7(PO4)6. Das erste gemischtvalente Phosphat mit Cr(II) und Cr(III). Z KRIST-CRYST MATER 2010. [DOI: 10.1524/zkri.1993.205.part-1.69] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Abstract
Cr7(PO4)6 [Cr3
2+ Cr4
3+(PO4)6] can be obtained reducing a mixture of Cr2O3 and CrPO4 by CrP (950°C, 48h, 100 mg iodine as mineralizer). By means of chemical transport reactions (transport agent iodine; 1050 → 950°C) the compound has been separated from its neighbour phases and crystallized (dark brown, transparent crystals; pinacoidal, edge length up to 0.5 mm). Cr7(PO4)6 [P [unk]; Z = 1; a = 9.3184(19) Å, b = 8.0044(18) Å, c = 6.2532(14) Å, α = 100.982(9)°, β = 107.954(11)°, γ = 107.144(10)°] is isotypic to Fe7(PO4)6. The crystal structure refinement from single single crystal data led to a conventional residual R = 0.032 (3016 independent F
0, 170 parameters). For M = Cr2+ two different M–O-coordination polyhedra were observed; a compressed octahedron and a strongly distorted trigonal bipyramide. The influence of the Jahn-Teller effect on the coordination geometry of Cr2+ will be discussed. The Cr3+ ions (2 sites) are surrounded octahedrally by oxygen (1,884 Å ≤ d
Cr–O ≤ 2,071 Å). Zn3Cr4(PO4)6 also isotypic to Fe7(PO4)6 has been synthesized and characterized by its Guinier powder pattern [a = 9.248(4) Å, b = 7.835(3) Å, c = 6.277(2) Å, α = 101.59(4)°, β = 108.10(3)°, γ = 105.34(4)°].
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Glaum R, Schmidt[2] A. Contributions on thermal behaviour and crystal chemistry of anhydrous phosphates. XIX. Tri-chromium(II)-bis-phosphate Cr3(PO4)2 (? Cr6(PO4)4) - A transition metal(II)-orthophosphate with new structure type. Z Anorg Allg Chem 1997. [DOI: 10.1002/zaac.19976231032] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Cotton F, Daniels LM, Murillo CA. Synthesis and X-ray structure of two relatively air-stable chromium(II) 3-pyridinesulphonate compounds. Polyhedron 1992. [DOI: 10.1016/s0277-5387(00)83566-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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