Crystal chemistry of lithium in octahedrally coordinated structures. I. Synthesis of Ba8(Me6Li2)O24 (Me = Nb or Ta) and Ba10(W6Li4)O30. II. The tetragonal bronze phase in the system BaONb2O5Li2O
1973; Elsevier BV; Volume: 8; Issue: 1 Linguagem: Inglês
10.1016/0022-4596(73)90013-3
ISSN1095-726X
AutoresT. Negas, R.S. Roth, H.S. Parker, W. S. Brower,
Tópico(s)Inorganic Chemistry and Materials
ResumoThe preparation, single crystal growth, and crystallographic properties of a close-packed, eight-layer, hexagonal (a = 5.803 Å, c = 19.076 Å) modification having the stoichiometry Ba8Nb6Li2O24 and of a close-packed, ten-layer, hexagonal (a = 5.760 Å, c = 23.742 Å) phase with Ba10W6Li4O30 stoichiometry are discussed. The isostructural Ba8Ta6Li4O24 form of the eight-layer phase was also prepared (a = 5.802 Å, c = 19.085 Å). Proposed crystal structures involve the pairing of lithium and metal (Nb, Ta, or W) octahedra to yield face-sharing units. The relationship of this phenomenon to other known close-packed phases containing Li is demonstrated. An investigation of the Ba8Nb6Li2O24Ba10W6Li4O30 system is reported. A tetragonal bronze phase homogeneity region was delimited at 1200°C in the BaONb2O5Li2O system. A new orthorhombic phase (a = 10.197 Å, b = 14.882 Å, c = 7.942 Å) was prepared with the stoichiometry Ba4Li2Nb10O30.
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