A functional fluid composition is provided which comprises a plurality of different phosphazene compounds of the general formula (P=N).sub.n (R).sub.a (R').sub.b (R").sub.c (R'").sub.d wherein R is at least one alkoxy moiety described by the general formula --OCH.sub.2 (CF.sub.2).sub.y X, with X being hydrogen or fluorine and y being equal to 1 to about 10; R', R" and R'" are different aryloxy moieties, each of R', R" and R'" being selected from the group consisting of phenoxy, alkoxy phenoxys, alkyl phenoxys, chlorinated phenoxys, fluorinated phenoxys, aryl phenoxys, phenoxy phenoxys, fluoroalkyl phenoxys, fluoroalkoxy phenoxys, chlorinated phenoxy phenoxys, fluorinated phenoxy phenoxys and mixtures thereof; n is equal to 3 to about 4 for each of said phosphazene compounds, each of a, b, c and d is equal to or greater than zero such that the sum a+b+c+d is equal to 2n; and for the composition as a whole, the average value of each of a, b, c and d is greater than 0.