We determined the synthesis conditions for successive ionic layer deposition of the Sn ₁₆ (OH) _x PW ₁₉ O _y ·nH ₂ O nanolayers on silica surfaces. The synthesized layers were characterized using UV-Vis and FTIR absorption spectroscopies, X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), scanning electron microscopy (SEM), and atomic force microscopy (AFM). On heating the as-synthesized layers to 200-500 °C in air, incorporated water evaporate, while M-OH groups are condensed and concentration of the W-O-W and W-O-Sn bonds increase. The layers have amorphous agglomerate-like structure. The agglomerate size is from 20 to 100 nm. Upon heating to 600 °C, the size insignificantly increases, the agglomerate form being practically unchanged. The data obtained allow conclusion that the layers present a hybrid compound consisting of fragments of isopoly-(Sn _x O _y H _z ) and heteropoly-(H _x PW _y O _z ) compounds