A composition is described including a first fluorinated
hydrocarbon compound according to the formula:wherein R1, R2, R3, R4, and R5 are each independently H, F, Cl, Br, or I, n is 0, 1, 2, or 3, and each R′ group is independently H, F, Cl, Br, or I, with the proviso that zero to three of R1, R2, R3, R4, and R5 are F;a second fluorinated
hydrocarbon compound according to the formula:wherein m is 0 or 1, and R6, R7, and R8 are each independently H, F, Cl, Br, or I, with the proviso that one of R6, R7, and R8 is F; anda third fluorinated
hydrocarbon compound according to the formula:wherein R9, R10, R11, R12 and R13 are each independently H, Cl, Br, or I.