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Title: A sodium gadolinium phosphate with two different types of tunnel structure: Synthesis, crystal structure, and optical properties of Na{sub 3}GdP{sub 2}O{sub 8}

Journal Article · · Journal of Solid State Chemistry
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  1. Fujian Institute of Research on the Structure of Matter, State Key Laboratory of Structural Chemistry, Graduate School of the Chinese Academy of Sciences, Fuzhou, Fujian 350002 (China)

A sodium gadolinium phosphate crystal, Na{sub 3}GdP{sub 2}O{sub 8}, has been synthesized by a high-temperature solution reaction, and it exhibits a new structural family of the alkali-metal-rare-earth phosphate system. Although many compounds with formula M{sub 3}LnP{sub 2}O{sub 8} have been reported, but they were shown to be orthorhombic [R. Salmon, C. Parent, M. Vlasse, G. LeFlem, Mater. Res. Bull. 13 (1978) 439] rather than monoclinic as shown in this paper. Single-crystal X-ray diffraction analysis shows the structure to be monoclinic with space group C2/c and the cell parameters: a=27.55 (25), b=5.312 (4), c=13.935(11) A, {beta}=91.30(1){sup o}, and V=2038.80 A{sup 3}, Z=4. Its structure features a three-dimensional GdP{sub 2}O{sub 8}{sup 3-} anionic framework with two different types of interesting tunnels at where Na atoms are located by different manners. The framework is constructed by Gd polyhedra and isolated PO{sub 4} tetrahedra. It is different from the structure of K{sub 3}NdP{sub 2}O{sub 8} [R. Salmon, C. Parent, M. Vlasse, G. LeFlem, Mater. Res. Bull. 13 (1978) 439] with space group P2{sub 1}/m that shows only one type of tunnel. The emission spectrum and the absorption spectrum of the compound have been investigated. Additionally, the calculations of band structure, density of states, dielectric constants, and refractive indexes have been also performed with the density functional theory method. The obtained results tend to support the experimental data. - Graphical abstract: Projection of the structure of Na{sub 3}GdP{sub 2}O{sub 8} with a unit cell edge along the b-axis. The Na-O bonds are omitted for clarity.

OSTI ID:
21128427
Journal Information:
Journal of Solid State Chemistry, Vol. 181, Issue 9; Other Information: DOI: 10.1016/j.jssc.2008.04.013; PII: S0022-4596(08)00204-1; Copyright (c) 2008 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA); ISSN 0022-4596
Country of Publication:
United States
Language:
English