In recent years borate-based crystals has attracted substantial interest among the research community. The overall importance of this family of materials is reflected in miscellaneous articles and several reviews that have been published over the years. Crystalline borate materials exhibit numerous interesting physical properties, which make them promising for further practical applications. Diversity of functional characteristics results from their high structural flexibility caused in the linkage of planar/non–planar BO₃ groups and BO₄ tetrahedra, which can occur as isolated or condensed structural units. This report is a brief review on crystal chemistry and structure features of anhydrous/high-temperature borates. Polymorphism of boron-oxygen radicals has been considered basing on cations’ nature and synthesis conditions. Analysis of the laws governing borates structures and general principles of their systematics was discussed. As a result, an alternative classification of anhydrous compounds has been considered. It is based on four orders of their subdivision: (1) by the variety of anion formers, (2) by the cation charge, (3) by the N = N_M:N_B, i.e., ratio of metal atoms number to the ratio of boron atoms number (N-factor) value indicating the borate structural type (if it is known), (4) by the cation type and size.

A Tb³⁺:YAB crystal was grown using a high-temperature solution growth on dipped seeds technique. Polarized ground state absorption and fluorescence spectra from the ⁵D₄ level, as well as a fluorescence decay curves of ⁵D₄ and ⁵D₃ levels, were recorded at room temperature. Radiative properties such as emission probabilities, branching ratios, and radiative lifetime were investigated within the theory of 4f-4f transition intensity in the case of the intermediate configuration interaction.

YAl3(BO3)4 (YAB) crystals 10 × 10 × 8 mm in dimensions were grown on point seeds from a potassium-trimolybdate-based high-temperature solution. The crystals were used as substrates for liquid-phase ep

The solubility of NdAl₃(BO₃)₄ crystals in a 69.4 wt% K₂Mo₃O₁₀−18.1 wt% Nd₂O₃−12.5 wt% B₂O₃ multicomponent flux has been investigated. Their growth kinetics was determined in the temperature range of 1050–1000 °C and growth rates were found to be within 0.05–0.14 μm min⁻¹ depending on fluxed melt supercooling (supersaturation). With increased supercooling up to 15 °C, the growth rate rises linearly, but then reaches a temperature plateau and decreases slowly because of spontaneous nucleation in the fluxed melt volume at a comparatively higher supercooling. The growth rate data were analyzed according to a simple diffusion model. NdAl₃(BO₃)₄ single crystals (7 × 10 × 20 mm) have been obtained by high-temperature solution growth on dipped seeds.