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The structure of an Al{sup 3+} stabilized phase Li{sub 3-3x}Al{sub x}BO{sub 3} (x{approx}0.18) was determined by means of single crystal X-ray diffraction. This phase crystallizes in space group P6{sub 1}22 or P6{sub 5}22, with lattice constants a=4.9019(5)A, c=17.538(2)A and Z=6. The unit cell consists of six layers of BO{sub 3} groups with Li{sup +} cations distributing statistically on five crystallographic sites, none of which is fully occupied. The Li sites are close to each other and a three-dimensional network results when Li sites only within 1.65A are connected. Significant ionic conductivity was observed for this phase.

A new compound, Li(4)WaB(2)O(6), has been synthesized by solid-state reaction and its structure has been determined from powder X-ray diffraction data by direct methods. The refinement was carried out using the Rietveld methods and the final refinement converged with R-p = 10.4% R-wp = 14.2%, R-exp = 4.97%. This compound belongs to the orthorhombic space group Pnnm, with lattice parameters a 9.24036(9) Angstrom, b = 8.09482(7) Angstrom, and c = 3.48162(4) Angstrom. Fundamental building units are isolated [BO3](3-) anionic groups, which are all parallel to the a-b plane stacked along the c-axis. The Ca atoms are six-coordinated by the O atoms to form octahedral coordination polyhedra, which are joined together through edges along the c-axis, forming infinitely long three-dimensional chains. The Li atoms have a four-fold and a five-fold coordination with O atoms that lead to complex Li-O-Li chains that also extend along the c-axis. The infrared spectrum of Li4CaB2O6 was also studied, which is consistent with the crystallographic study. (C) 2003 Elsevier Inc. All rights reserved.

A new compound, beta-SrGaBO4, has been attained through solid phase transition from alpha-SrGaBO4 at high temperatures. Its crystal structure has been determined from powder X-ray diffraction data by direct methods. The refinement was carried out using the Rietveld method and the final refinement converged with Rp = 11.42 % and Rwp = 15.16 %. It has an orthorhombic P2(1)2(1)2 space group with cell parameters a = 15.3706(2) Angstrom b = 8.992 1 (1) Angstrom, c = 5.919 1 (1) A, and Z = 8. The structure of beta-SrGaBO4 is built up from Ga2BO8 units formed by two GaO4 tetrahedra and one BO3 triangle, and Sr2O12 units formed by two SrO7 groups. Tetrahedra [GaO4] are linked by shared O(3) and O(7) atoms to form infinite chains along the e axis. (C) 2002 Elsevier Science, (USA).

The ternary system Li2O–Al2O3–B2O3 is reinvestigated with solid-state reaction and X-ray powder diffraction technique to clarify some long-standing uncertainties. The phase relations are constructed based on the phase identifications of 51 ternary samples. Six ternary compounds, Li2AlB5O10, LiAlB2O5, Li3AlB2O6, Li2AlBO4, LiAl7B4O17 and a compound with a composition close to 0.66Li2O·0.06Al2O3·0.28B2O3, are observed or confirmed in this system, and the thermal stability of these ternary compounds is also discussed on the basis of DTA experimental results.

A new compound, Li3AlB2O6, has been synthesized by solid state reaction and its structure has been solved and refined from single-crystal and power X-ray diffraction data. This compound crystallizes in a triclinic unit cell (space group P (1) over bar) with lattice parameters a = 4.876(8) Angstrom, b = 6.191(16) Angstrom, c = 7.910(20) Angstrom, alpha = 74.46(18)degrees, beta = 89.44(17)degrees, and gamma = 89.52(18)degrees. There are 2 formulas per unit cell and 12 atoms in the asymmetric unit. This structure is built up of infinite [Al-2(BO3)(4)](infinity)(6-) complex chains that are parallel to the a axis and separated by Li atoms. Although this structure exhibits many structural similarities to a previously reported compound with the same chemical composition, its unit cell and its powder diffraction pattern are different and so is the distribution of the Li atoms. Infrared and thermal analyses were also performed to compare with previous reports. (C) 2002 Elsevier Science.

The subsolidus phase relations of the binary system Bi2O3–CeO2have been investigated. It was found that CeO2forms neither a compound nor a solid solution with Bi2O3. CeO2, however, can stabilize β-Bi2O3over a wide composition range. The stabilization depends on the contents of CeO2as a second phase and on the heat treatment. A stabilization mechanism is proposed.