Structural investigations of new calcium-rare earth (R) oxyborates with the composition Ca[sub 4]RO(BO[sub 3])[sub 3]

Journal Article · · Chemistry of Materials; (United States)

OSTI ID:6492943

Norrestam, R; Nygren, M ^[1]; Bovin, J O ^[2]

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1. Stockholm Univ. (Sweden)
2. Univ. of Lund (Sweden)

A new series of calcium containing rare earth (R) borates has been synthesized by high-temperature synthesis for some of the trivalent R ions, viz., La[sup 3+], Nd[sup 3+], Sm[sup 3+], Gd[sup 3+], Er[sup 3+], and Y[sup 3+]. Characterization by X-ray diffraction and electron microscopy techniques has shown them to be isostructural with the compositions Ca[sub 4]RO(BO[sub 3])[sub 3]. The structure type of these new oxyborates, determined by single-crystal X-ray diffraction methods applied to Sm compounds, is related to the structure of a recently found calcium fluoroborate and also to common fluorapatite. For Ca[sub 4]SmO(BO[sub 3])[sub 3] the unit cell parameters are a = 8.114 (2), b = 16.061 (4), c = 3.579 (1) [angstrom] and [beta] = 101.38 (3)[degrees]. The space group is monoclinic noncentrosymmetric Cm with Z = 2. The structural model deduced was refined versus the amplitudes of the 547 most significant X-ray reflections, with sin ([theta])/[lambda] [le] 0.65 [angstrom][sup [minus]1], to an R value of 0.016. The occurrence of Ca, Sm, O, and B in the synthesized crystals were verified by parallel recording of electron energy-loss spectra (PEELS) in a high-resolution transmission electron microscope (HRTEM). The compositions of the crystal used for the X-ray structure investigation was determined by energy-dispersive X-ray analysis (EDX) analysis in a scanning electron microscopy to be Ca[sub 3.90]Sm[sub 1.10]O(BO[sub 3])[sub 3]. Studies on analogues of the present compounds toward their possible applications as a high-Nd concentration minilaser materials are in progress. 17 refs., 5 figs., 4 tabs.

• OSTI ID: 6492943
• Journal Information: Chemistry of Materials; (United States), Journal Name: Chemistry of Materials; (United States) Vol. 4:3; ISSN CMATEX; ISSN 0897-4756
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
ALKALINE EARTH METAL COMPOUNDS
BORATES
BORON COMPOUNDS
CALCIUM COMPOUNDS
CHEMICAL PREPARATION
CRYSTAL LATTICES
CRYSTAL STRUCTURE
ELECTRON MICROSCOPY
ERBIUM COMPOUNDS
GADOLINIUM COMPOUNDS
LANTHANUM COMPOUNDS
MICROSCOPY
MONOCLINIC LATTICES
NEODYMIUM COMPOUNDS
OXYGEN COMPOUNDS
RARE EARTH COMPOUNDS
SAMARIUM COMPOUNDS
SYNTHESIS
TRANSITION ELEMENT COMPOUNDS
YTTRIUM COMPOUNDS