Starting from an optimized synthesis of silylated phosphoric acid, OP(OSiMe3)(3), a borate salt bearing the [P(OSiMe3)(4)](+) cation was generated in the reaction of OP(OSiMe3)(3) with [Me3Si-H-SiMe3][B(C6F5)(4)], isolated, and fully characterized. Analogously to the protonated species, phosphoric acid (H3PO4) reaction of OP(OSiMe3)(3) with a base led to the formation of the unknown [O2P(OSiMe3)(2)](-) anion, which could be crystallized as potassium salt and structurally characterized, too. Both [P(OSiMe3)(4)](+) and [O2P(OSiMe3)(2)](-) can be regarded as the formal autoprotolysis products of OP(OSiMe3)(3).( )