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The investigations of the crystal structure, magnetic and electronic properties of the Co$_3$BO$_5$ at high temperatures were carried out using powder x-ray diffraction, magnetic susceptibility, electrical resistivity, and thermopower measurements. The orthorhombic symmetry (Sp.gr. Pbam) was established at 300 K and no evidence of structural phase transitions was found up to 1000 K. The thermal expansion of the crystal lattice is strongly anisotropic. At $T

Single crystals of ludwigite Ni2MnBO5 were synthesized by flux growth technique. The detailed structural and magnetic characterizations of the synthesized samples have been carried out. The cations composition of the studied crystal was determined using X-ray diffraction and EXAFS technique, the resulting composition is differ from the content of the initial Mn2O3 - CuO components of flux. Magnetic susceptibility measurements and the calculations of the exchange integrals in frameworks of indirect coupling model revealed strong antiferromagnetic interactions and appearance of magnetic ordering phase at the temperature T=85 K. The hypothesis of the existence of several magnetic subsystems was supposed.