Synthesis and crystal structures of CaY{sub 2}Ge{sub 3}O{sub 10} and CaY{sub 2}Ge{sub 4}O{sub 12}

Journal Article · Sun Jan 15 00:00:00 EST 2006 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1016/j.jssc.2005.10.023· OSTI ID:20784860

Yamane, Hisanori ^[1]; Tanimura, Ryouji ^[1]; Yamada, Takahiro ^[2]; Takahashi, Junichi ^[2]; Kajiwara, Takashi ^[3]; Shimada, Masahiko ^[4]

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1. Center for Interdisciplinary Research, Tohoku University, 6-3 Aramaki, Aoba, Aoba-ku, Sendai 980-8578 (Japan)
2. Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577 (Japan)
3. Department of Chemistry, Graduate School of Science, Tohoku University, 6-3 Aramaki, Aoba, Aoba-ku, Sendai 980-8578 (Japan)
4. Akita National College of Technology, 1-1 Bunkyo-cho Iijima, Akita 011-8511 (Japan)

New compounds CaY{sub 2}Ge{sub 3}O{sub 10} and CaY{sub 2}Ge{sub 4}O{sub 12} were prepared by heating mixtures of CaCO{sub 3}, Y{sub 2}O{sub 3} and GeO{sub 2} at 1200 deg. C. CaY{sub 2}Ge{sub 3}O{sub 10} is stable at 1300 deg. C, while CaY{sub 2}Ge{sub 4}O{sub 12} decomposes into a melt and CaY{sub 2}Ge{sub 3}O{sub 10} at approximately 1250 deg. C. We obtained single crystals of CaY{sub 2}Ge{sub 3}O{sub 10} by cooling a sample with an initial composition of Ca:Y:Ge=1:2:8 from 1300 deg. C with a rate of -6 deg. C/h. The crystal structure of CaY{sub 2}Ge{sub 3}O{sub 10} was determined by single crystal X-ray diffraction. CaY{sub 2}Ge{sub 3}O{sub 10} crystallizes in the monoclinic space group P2{sub 1}/c with a=6.0906(8), b=6.8329(8), c=18.752(2)A and {beta}=109.140(3){sup o}, Z=4, and R{sub 1}=0.029 for I>2{sigma}(I). In the structure of CaY{sub 2}Ge{sub 3}O{sub 10}, Ca and Y atoms are situated disorderly in three 7-fold coordination sites between isolated germanate groups of triple GeO{sub 4} tetrahedra, Ge{sub 3}O{sub 10}. The structural formula of CaY{sub 2}Ge{sub 3}O{sub 10} is expressed as (Ca{sub 0.45}Y{sub 0.55})(Ca{sub 0.46}Y{sub 0.54})(Ca{sub 0.09}Y{sub 0.91})Ge{sub 3}O{sub 10}. The crystal structure of CaY{sub 2}Ge{sub 4}O{sub 12} was analyzed by the Rietveld method for the X-ray powder diffraction pattern. CaY{sub 2}Ge{sub 4}O{sub 12} is isotypic with SrNa{sub 2}P{sub 4}O{sub 12}, crystallizing in the orthorhombic space group P4/nbm, a=9.99282(6), c=5.06701(4)A, Z=2, R{sub wp}=0.092, R{sub p}=0.067. CaY{sub 2}Ge{sub 4}O{sub 12} contains four-membered GeO{sub 4}-tetrahedra rings, Ge{sub 4}O{sub 12}. Eight-fold coordinated square-anitiprism sites and 6-fold octahedral sites between the layers of the Ge{sub 4}O{sub 12} rings are occupied by Y atom and Ca/Y atoms, respectively The structural formula is Y(Ca{sub 0.5}Y{sub 0.5}){sub 2}Ge{sub 4}O{sub 12}.

• OSTI ID: 20784860
• Journal Information: Journal of Solid State Chemistry, Vol. 179, Issue 1; Other Information: DOI: 10.1016/j.jssc.2005.10.023; PII: S0022-4596(05)00477-9; Copyright (c) 2005 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

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
CALCIUM CARBONATES
GERMANATES
GERMANIUM OXIDES
LAYERS
MONOCLINIC LATTICES
MONOCRYSTALS
ORTHORHOMBIC LATTICES
SPACE GROUPS
SYNTHESIS
X-RAY DIFFRACTION
YTTRIUM OXIDES