Abstract: New methods for the preparation of a monofluoro-substituted derivative of the closo-decaborate anion [2-B₁₀H₉F]^2– have been developed. Various synthetic strategies have been used, where Bu₄NF, Me₄NF, KF/18-crown-6, and NH₄HF₂ act as sources of the F^– anion. A feature of the proposed methods is the absence of HF as a fluorinating agent in the reaction mixture. In the course of the work, the optimal conditions for the synthesis of [2-B₁₀H₉F]^2– have been determined and the reaction products have been characterized. Using theoretical modeling methods, the main indices of reactivity of monofluorinated derivatives of the closo-decaborate anion have been calculated. The influence of solvation effects on the nucleophilicity of target objects has been studied. The structure of the obtained compounds has been confirmed by ¹H, ¹¹B, ¹⁹F NMR spectroscopy, and ESI mass spectroscopy.