Crystal Structures of Endotaxic Phases in Europium Potassium Silicate Having a Pellyite Unit Cell

Journal Article · Mon Nov 15 04:00:00 EST 2010 · Crystallography Reports

DOI:https://doi.org/10.1134/S1063774510060222· OSTI ID:22054065

Aksenov, S M ^[1]; Taroev, V K ^[2]

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1. Russian Academy of Sciences, Shubnikov Institute of Crystallography (Russian Federation)
2. Siberian Branch, Russian Academy of Sciences, Vinogradov Institute of Geochemistry and Analytical Chemistry (Russian Federation)

The structures of three phases of the synthesized europium potassium silicate were determined by X-ray diffraction. Two of these phases crystallize in a new structural type. The chemical formulas of the phases were determined. The orthorhombic unit-cell parameters of all three phases are equal: a = 14.852(1) A, b = 15.902(1) A, c = 7.243(1) A, sp. gr. P2{sub 1}2{sub 1}2 (phase I) and sp. gr. Pbam (phases II and III). The structures were solved by direct methods and refined from X-ray diffraction data collected from one crystal to R = 0.0271, 0.0479, and 0.0582 based on 4370, 3320, and 2498 reflections, respectively, with |F| > 3{sigma}(F). The crystal- chemical formulas of the phases (Z = 4) are K{sub 3}Eu{sub 3+}[Si{sub 6}O{sub 15}] . 2H{sub 2}O, K{sub 3}Eu{sup 3+}[Si{sub 6}O{sub 13}(OH){sub 4}] . 2H{sub 2}O, and K{sub 3}Eu{sup 3+}[Si{sub 4}O{sub 9.5}(OH)](OH){sub 2}. 5.5H{sub 2}O. The structure of phase I consists of silicon-oxygen sheets [Si{sub 6}O{sub 15}] analogous to those found in the isostructural compound K{sub 3}Nd[Si{sub 6}O{sub 15}] . 2H{sub 2}O. In the structures of phases II and III, the ribbons [Si{sub 6}O{sub 17}] and [Si{sub 8}O{sub 21}] run along the shortest c axis and are linked together by Eu{sup 3+} octahedra and trigonal prisms to form three-dimensional layered and framework structures containing K atoms between the sheets and in the channels. The fragments are also linked through hydrogen bonds with the participation of OH groups and water molecules.

• OSTI ID: 22054065
• Journal Information: Crystallography Reports, Journal Name: Crystallography Reports Journal Issue: 6 Vol. 55; ISSN CYSTE3; ISSN 1063-7745
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
CRYSTALS
EUROPIUM COMPOUNDS
EUROPIUM IONS
ORTHORHOMBIC LATTICES
OXYGEN
POTASSIUM SILICATES
PRISMS
REFLECTION
SHEETS
SILICON
WATER
X-RAY DIFFRACTION