DSpace Repository

Crystal Structure of apatite type rare-earth silicate (Sr2RE2) (RE6)(SiO4)(6)O-2 (RE = La, Pr, Tb, Tm, and Y)

Show simple item record

dc.contributor.author Leu, Lii-Cherng
dc.contributor.author Sherin, T
dc.contributor.author Sebastian, M T
dc.contributor.author Zdzieszynski, S
dc.contributor.author Misture, S
dc.contributor.author Ubic, R
dc.date.accessioned 2013-11-19T06:26:01Z
dc.date.available 2013-11-19T06:26:01Z
dc.date.issued 2011
dc.identifier.citation Journal of the American Ceramic Society 94(8):2625-2632;Aug 2011 en_US
dc.identifier.issn 0002-7820
dc.identifier.uri http://ir.niist.res.in:8080/jspui/handle/123456789/768
dc.description.abstract The crystal structures of apatite-type (Sr2RE2)(RE6)(SiO4)(6)O-2 (RE = La, Pr, Tb, Tm, and Y) ceramics prepared by conventional solid-state processing has been examined. The phase and structure analysis was carried out using powder X-ray diffraction (XRD) and transmission electron microscopy. Electron diffraction and Rietveld structure refinement of XRD data indicated that (Sr2RE2)(RE6)(SiO4)(6)O-2 (RE = La, Pr, Tb, and Y) has a typical oxyapatite-type structure, A(4)(I)A(6)(II)(BO4)(6)O-2 in space group P6(3)/m (No. 176), where the A(I) site is shared equally and randomly by Sr and RE ions, A(II) is occupied by RE ions only, and B is occupied by Si. As the metaprism twist angle in this lanthanide series should increase as the size of RE decreases, the unrealistically low metaprsim twist angle for (Sr2Tm2)(Tm-6)(SiO4)(6)O-2 suggested that the hexagonal metric of apatite might not be sustained and the symmetry reduced to monoclinic, space group P2(1)/m (No. 11), in order to compensate for the shorter Tm-O bond length. The P2(1)/m model for (Sr2Tm2)(Tm-6)(SiO4)(6)O-2 also yields a better fit and improvement in bond valence as compared with P6(3)/m model. en_US
dc.language.iso en en_US
dc.publisher Wiley en_US
dc.subject Microwave dielectric-properties en_US
dc.subject Oxide-ion conduction en_US
dc.subject BA(ZN1/3TA2/3)O-3 Ceramics en_US
dc.subject Lanthanum silicates en_US
dc.subject Toxic metals en_US
dc.subject Oxyapatites en_US
dc.subject Luminescence en_US
dc.title Crystal Structure of apatite type rare-earth silicate (Sr2RE2) (RE6)(SiO4)(6)O-2 (RE = La, Pr, Tb, Tm, and Y) en_US
dc.type Article en_US


Files in this item

This item appears in the following Collection(s)

Show simple item record

Search DSpace


Advanced Search

Browse

My Account