Synthesis and study of anhydrous lanthanide orthophosphate ($\mathrm{Ln}=\mathrm{La},\mathrm{Pr},\mathrm{Nd},\mathrm{Sm}$) nanowhiskers

The effect of hydrothermal synthetic conditions on the obtaining of lanthanide orthophosphates $\mathrm{LnPO}_4$ ($\mathrm{Ln}=\mathrm{La},\mathrm{Pr},\mathrm{Nd},\mathrm{Sm}$) with different structure, size and shape of particles was revealed. The optimum conditions for preparation of anhydrous nanoscale lanthanide orthophosphates with monoclinic structure were determined. The prepared nanowhiskers had lengths ranging from 0.4 m (for $\mathrm{LaPO}_4$) to $5\mu$m (for $\mathrm{SmPO}_4$), and the diameter – from $30$ nm (for $\mathrm{LaPO}_4$) to 200 nm (for $\mathrm{SmPO}_4$). The size of particles synthesized under similar conditions increased with decreased of lanthanide ion radius.