TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Compounds: (I) are of formula (Kt)y+.((CnHmF2n+1-m)xPClyF6-x-y)-y (I').(Kt)y+ = inorganic cation (preferably a Group 1-12 metal cation) or organic cation (preferably an ammonium, phosphonium, uronium, thiouronium, guanidinium or heterocyclic cation);n = 1-12 (preferably 2-4);m = 0 to 2n + 1 (preferably 0);x = 1-4 (preferably 3);y = 1-4 (preferably 1;x + y = 5 or less.In particular the cation of (I)/(I') is ((C2F5)3PClF2)-, ((C3F7)3PClF2)- or ((C4F9)3PClF2)-; and the cation is an alkali metal (i.e. lithium, sodium potassium rubidium or cesium) cation or an imidazolium, pyridinium, pyrrolidinium, ammonium, phosphonium or guanidinium organic cation. Preparation: Claimed preparation of (I) involves reacting a chloride salt (III) with an organo-fluorophosphorane (IV). Specifically (I') is prepared by reacting a chloride salt of formula (Kt)y+.Cl-y (III') with an organo-fluorophosphorane of formula (CnHmF2n+1-m)xPClyF5-x (IV'). Reaction is preferably carried out in at 40 to 180 degrees C in solvent, specifically selected from nitriles, dialkyl carbonates, glymes, dialkyl ethers, cyclic ethers, dimethyl formamide, dimethyl sulfoxide, dichloromethane and/or water. SPECIFIC COMPOUNDS - 9 Compounds (I) are disclosed, e.g. tetrabutylammonium tris-(pentafluoroethyl)-difluorochlorophosphate (Ia), benzyl-triethylammonium tris-(pentafluoroethyl)-difluorochlorophosphate, 1-ethyl-3-methyl-imidazolium tris-(pentafluoroethyl)-difluorochlorophosphate, 1-butyl-1-methyl-pyrrolidinium tris-(pentafluoroethyl)-difluorochlorophosphate and trihexyl-tetradecylphosphonium tris-(pentafluoroethyl)-difluorochlorophosphate. (Structure of product of Example 1, page 12, as (Ia))    EXAMPLE - A solution of 7.04 g tetrabutylammonium chloride and 12.0 g tris-(pentafluoroethyl)-difluorophosphorane in 20 ml acetonitrile wsa stirred at room temperature for 1 hour. Volatiles were evaporated under vacuum and the residue was dried for 2 hours at 7 Pa and 40-50 degrees C to give 17.0 g (95.5% based on tetrabutylammonium chloride) of tetrabutylammonium tris-(pentafluoroethyl)-difluorochlorophosphate (Ia) as a viscous oil.