A re-investigation of the crystal structure and luminescence of BaCa{sub 2}MgSi{sub 2}O{sub 8}:Eu{sup 2+}

Journal Article · Wed Jun 15 00:00:00 EDT 2011 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1016/j.jssc.2011.04.030· OSTI ID:21580119

Park, Cheol-Hee ^[1]; Kim, Tae-Hoon ^[1]; Yonesaki, Yoshinori; Kumada, Nobuhiro ^[2]

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1. LG Chem Research Park, Daejeon 305-380 (Korea, Republic of)
2. University of Yamanashi, Miyamae-Cho 7-32, Kofu 400-8511 (Japan)

Barium calcium magnesium silicate (BaCa{sub 2}MgSi{sub 2}O{sub 8}), a compound whose space group was obtained via X-ray diffraction data, was re-investigated using neutron diffraction techniques. A combined powder X-ray and neutron Rietveld method revealed that BaCa{sub 2}MgSi{sub 2}O{sub 8} crystallizes in the trigonal space group P3-bar (Z=1, a=5.42708(5) A, c=6.79455(7) A, V=173.310(4) A{sup 3}; R{sub p}/R{sub wp}=5.52%/7.63%), instead of the previously believed space group P3-bar m1. The difference in the two structures arises from the displacement of the O2 atom. Blue emission from Ba{sub 0.98}Eu{sub 0.02}Ca{sub 2}MgSi{sub 2}O{sub 8} under 325-nm excitation is ascribed to the 4f{sup 6}5d{sup 1}{yields}4f{sup 7} transitions of Eu{sup 2+} ions at Ba sites and Ca sites. Site assignment of Eu{sup 2+} ions in the titled compound was performed by analysis of emission spectra at temperatures in the range of 4.2-300 K. - Graphical abstract: A combined powder X-ray and neutron Rietveld method reveals that BaCa{sub 2}MgSi{sub 2}O{sub 8} crystallizes in the trigonal space group P3-bar , instead of the previously believed space group P3-bar m1 from X-ray diffraction data. Highlights: > Re-investigation of the structure using neutron diffraction data. > The correct space group is P3-bar , not P3-bar m1. > Identification of Eu{sup 2+} sites using temperature-variable luminescence.{yields} The emission at the shorter wavelength corresponds to the Ba site in the compound.

• OSTI ID: 21580119
• Journal Information: Journal of Solid State Chemistry, Vol. 184, Issue 6; Other Information: DOI: 10.1016/j.jssc.2011.04.030; PII: S0022-4596(11)00198-8; Copyright (c) 2011 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; ISSN 0022-4596
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
BARIUM
CALCIUM
EMISSION SPECTRA
EUROPIUM IONS
EXCITATION
LUMINESCENCE
MAGNESIUM SILICATES
NEUTRON DIFFRACTION
NEUTRONS
SPACE GROUPS
TRIGONAL LATTICES
X RADIATION
X-RAY DIFFRACTION
ALKALINE EARTH METAL COMPOUNDS
ALKALINE EARTH METALS
BARYONS
CHARGED PARTICLES
COHERENT SCATTERING
CRYSTAL LATTICES
CRYSTAL STRUCTURE
DIFFRACTION
ELECTROMAGNETIC RADIATION
ELEMENTARY PARTICLES
ELEMENTS
EMISSION
ENERGY-LEVEL TRANSITIONS
FERMIONS
HADRONS
IONIZING RADIATIONS
IONS
MAGNESIUM COMPOUNDS
METALS
NUCLEONS
OXYGEN COMPOUNDS
PHOTON EMISSION
RADIATIONS
SCATTERING
SILICATES
SILICON COMPOUNDS
SPECTRA
SYMMETRY GROUPS