5 H 2 O: revision of structure model and structural formula
Abstract. The crystal structure of the K, Ti analogue of ilímaussite-(Ce), (Ba,K,Na,Ca) 11-12 (REE,Fe,Th) 4 (Ti,Nb) 6 (Si 6 O 18 ) 4 (OH) 12 Á 4.5 H 2 O, from the Yukspor mountain, Khibiny massif, Kola peninsula, Russia, has been solved by direct methods and refined to R 1 ¼ 0.077 on the basis of 17...
Main Authors: | , , , , , |
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Language: | English |
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Online Access: | http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.1059.919 http://www.krist.unibe.ch/pdf/2003/zk0306_392.pdf |
Summary: | Abstract. The crystal structure of the K, Ti analogue of ilímaussite-(Ce), (Ba,K,Na,Ca) 11-12 (REE,Fe,Th) 4 (Ti,Nb) 6 (Si 6 O 18 ) 4 (OH) 12 Á 4.5 H 2 O, from the Yukspor mountain, Khibiny massif, Kola peninsula, Russia, has been solved by direct methods and refined to R 1 ¼ 0.077 on the basis of 1762 reflections with |F o | ! 4sF. The mineral is rhombohedral, R32, a ¼ 10.708(2), c ¼ 60.073(11) A, V ¼ 5965.2(17) A 3 . The structure is based upon a heteropolyhedral framework that consists of layers of corner-linked polyhedra. The SiO 4 tetrahedra share corners to form 6-membered rings which are further interlinked via REEO 6 trigonal prisms and Tij 6 octahedra (j ¼ O, OH). The obtained structure model is different from that recently reported by |
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