TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Salts: The new salts have a cation selected from pyridinium, pyridazinium, pyrimidinium, pyrazinium, imidazolium, thiazolium, oxazolium and 1,2,4-triazolium cations of the formulae (i)-(viii).R1-6 = the same or different substituents, which may be bound directly with one another by a single or double bond and are H, halogen (not bound directly with N) or 1-8 C alkyl, which may be partly or completely substituted by other groups, preferably F, Cl, N(CnF(2n+1-x)Hx)2, O(CnF(2n+1-x)Hx), SO2(CnF(2n+1-x)Hx), CnF(2n+1-x)Hx with n greater than 1 and less than 6 and x greater than 0 and not more than 2n+1.Preferred Preparation: The salts are prepared by neutralizing the acid, preferably with bases, especially (hydr)oxides, hydrides, amides, carbonates, phosphines or amines. The difluorotris(perfluoroalkyl)phosphorane or trifluorobis(perfluoroalkyl)phosphorane is of formula (CnF2n+1)mPF5-m (III).n = 1-8, preferably 1-4;m = 2 or 3.The temperature of the reaction mixture during the heating stage is room temperature to 150degreesC, preferably 100-145degreesC, especially 135-140degreesC and the heating time is 1-150, preferably 10-25, especially 18-22 hours. The reaction medium is water or a water-based mixture. SPECIFIC COMPOUNDS - Use of difluorotris(pentafluoroethyl)phosphorane, difluorotris(n-nonafluorobutyl)phosphorane and difluorotris(n-heptafluoropropyl)phosphorane as difluorotris(perfluoroalkl)phosphorane is specifically claimed. Use of trifluorobis-(n-nonafluorobutyl)phosphorane as trifluorobis(perfluoroalkl)phosphorane is specifically claimed.    EXAMPLE - 3.53 g water were added to 2.93 g 40 wt.% hydrofluoric acid, to give a mixture containing 58.6 mmole HF and 294 mmole water). This was cooled with an ice bath, then 25.03 g (58.7 mmole) difluorotris(pentafluoroethyl)phosphorane, (C2F5)3PF2 (IIIA), were added in 3 minutes, with stirring. (IIIA) dissolved completely, giving a colorless, clear solution of H+((C2F5)3PF3)- in water. The solution was stirred at room temperature for 15 minutes, then heated under reflux for 14 hours at an oil bath temperature of 135-140degreesC. Then 4.83 g water were added, heating under reflux was continued for 6 hours. After cooling to room temperature, 24.81 g clear solution were obtained. 3.95 g 2-phase liquid, comprising 2.11 g C2F5H, 1.5 g HF and 0.34 g (IIIA), were obtained in a trap cooled with dry ice. Distillation of aqueous HF solution from the reaction mixture gave 15.13 g almost pure bis(pentafluoroethyl)phosphinic acid (IIA). The yield was 86.5% with respect to (IIIA). (IIA) was purified by distillation at 125 Pa. The boiling point was 63-64degreesC.