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The crystal and magnetic structures of the lanthanum cobaltites Lao.6Sro.4CoO 3, Lao.(,Sro.,~Coo.~Feo.~O 3 and Lao.6Bao.4Coo.gFeo.~O~ have been studied by neutron powder diffraction at temperatures of 2, 300 and 90(1 K. All compounds undergo a phase transition from cubic to rhombohedral structure. Below the room temperature La~.~,Sro.,~CoO 3 becomes ferromagnetic while for the components with 10% Fe substituted for Co, we found an antiferromagnetic order.

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Phase equilibrium, glass-forming, properties and structure of the glasses in the TeO2--B203 system have been investigated. The phase diagram is a simple eutectic-like type without any compound formation. A wide region of stable phase separation has been established. A monotectic temperature at 934 K and nonvariant point at 73.6% TeO2 has been determined. The temperature dependence of the stable phase separation in the system has been studied. Some properties (density, transformation temperature, softening point, coefficient of thermal expansion, hardness, absorption in the UV and VIS region) of the tellurite borate glasses have been investigated. A structural interpretation of the glasses, on the basis of B 11 NMR spectra was undertaken and two coordination states of boron atoms have been established. A simple model of two telluriumboron-oxygen building units is presented.

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