The interaction of gaseous SiF4 and HF with surface of aqueous solution of LaCl3 leading to the formation of the LaF3–SiO2·nH2O nanocomposite and microtubes on its basis

Abstract

The interaction of gaseous SiF₄ and HF with lanthanum cations at the surface of aqueous solution of LaCl₃ has been studied for the first time. The reaction results in the formation of about 600 nm layer of a hydrophobic substance at the solution surface. According to the data of electron microscopy, IR Fourier spectroscopy, X-ray diffraction, and X-ray spectral microanalysis, the layer is formed by the LaF₃‒SiO₂·nH₂O nanocomposite and consists of 2D LaF₃ nanocrystals and SiO₂ spherical nanoparticles. Drying in air at room temperature is accompanied by the layer rolling with the formation of microtubes (20 μm in diameter and up to 300 μm long).