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The title compounds are prepared by solid state reaction of Li2CO3, MgO, MnO, and H3BO3 (Ar, 800 °C, 12 h).

The new title compounds are synthesized from mixtures of MgO, Nb2O5 or Ta2O5, and H3BO3 (1200 °C, 24 h).

Colorless, transparent single crystals of Ca3Sn2.2Ti0.8Al2O12 are prepared from a mixture of CaCO3, SnO2, TiO2, and α-Al2O3 in an atomic ratio of Ca:Sn:Ti:Al = 5:1:1:5 (1550 °C, 1 h).

Single crystals of penta­magnesium titanium(IV) tetra­oxide bis­(borate), Mg5TiO4(BO3)2, were prepared by slow cooling of the melt from 1623 K in air. The crystal is isostructural with the mineral ludwigite (Mg2FeO2BO3). The Mg and Ti atoms are coordinated by six O atoms and the B atom is coordinated by three O atoms. There are three Mg sites and one mixed site statistically occupied by Mg and Ti atoms. Atoms are at the following special positions: 2a (0, 0, 0) and 2d (0, 1 \over 2, 1 \over 2) for two Mg atoms, 4g (x, y, 0) for the mixed Ti/Mg site and the BO3 group, and 4h (x, y, 1 \over 2) for a third Mg and two oxide O atoms. MgO6 and (Ti/Mg)O6 octa­hedra are connected by sharing of edges to form zigzag folding layers along the c axis. Triangular prismatic tunnels are formed between the folding layers by sharing apical O atoms of the MgO6 and (Ti/Mg)O6 octa­hedra.

Single crystals of Mg5SnB2O10 are grown by heating Mg5SnB2O10 powder with H3BO3 at 1350 in air (Pt crucible, 12 h).

The title compounds are prepared by heating mixtures of MnO or Co3O4 and H3BO3 either at 1000 °C in Ar (Mn2B2O5) or at 850—900 °C in air (Co2B2O5) for 24 h.

Compounds in the CaO–B2O3–SnO2 system were prepared by solid-state reaction at 700–1100 °C in air. The phase relations in this system were investigated by powder X-ray diffraction (XRD). A previously reported calcium borostannnate, CaSn(BO3)2 (rhombohedral, R3¯ (No. 148), Z = 3, a = 4.85872(3), c = 16.07750(11) A), was synthesized in this system. Titanium(IV)-doped solid solutions, CaSn1−xTix(BO3)2 (0

Solid solutions of spinel-type cobalt-ruthenium oxides Co 3− x Ru x O y (0.50 ≤ x ≤ 0.70, y = 3.8–3.9) were prepared from Co 3 O 4 and RuO 2 powders by solid-state reaction at 1173–1273 K in air. The crystal structures of the solid solutions were refined by Rietveld analysis of powder X-ray diffraction (XRD) patterns. The solid solutions crystallized in cubic cells (space group: F d 3 ¯ m ) with formal compositions of (Co) tet [Co 2− x Ru x ] oct O y , where tet refers to the tetrahedral site and oct the octahedral one. The electrical transport property of the solid solutions exhibited semiconducting behavior and positive Seebeck coefficient in the temperature range from 298 to 1073 K. The thermal conductivity increased with increasing temperature. The maximum dimensionless figure of merit of 0.024 was measured for Co 2.35 Ru 0.65 O 3.86 at 973 K.