We report on the first examples of isolated silanol-silanolate anions, utilizing weakly coordinating phosphazenium counterions. The silanolate anions are synthesized by the reaction of the recently published phosphazenium hydroxide hydrate salt with siloxanes. The silanol-silanolate anions are postulated intermediates in the hydroxide mediated polymerization of aryl and alkyl siloxanes. The silanolate anions are strong nucleophiles due to the weakly coordinating character of the phosphazenium cation, which is perceptible in their activity in polysiloxane depolymerization. © 2019 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.