显强酸性，带有强烈的刺激性嗅味，能与水任意混和，煮沸分解为四氟化硅及氟化氢，对玻璃、陶瓷有腐蚀性，对皮肤和粘膜有强烈腐蚀性。已经制备了高硅氟硅酸。它们所需的额外二氧化硅含量要比 H2SiF6所代表的组成高18%。已报道了氟硅酸的制备和性质。氟硅酸可以作为磷酸盐肥料的主要副产物获得。可通过氯化钠中和用于制备氟硅酸钠。还可与氨进行中和生成氟化铵和二氧化硅 High-silic fluoro silicic acids have been prepared. They have desired amount of extra silica upto 18% more than the composition as represented by H2SiF6. Preparation and properties of fluosilicic acid have been reported. Fluosilicic acid can be obtained as a major byproduct of phosphate fertilizer industry.It can be used in the preparation of sodium fluorosilicate, via neutralization with sodium chloride. It can also undergo neutralization with ammonia to produce ammonium fluoride and silica.