Positron emitting compounds and methods of their production are provided. The compounds have the formula: (F)m G (R)n wherein each R is a group comprising at least one carbon, nitrogen, phosphorus or sulfur atom and G is joined to R through said carbon, nitrogen, phosphorus or sulfur atom G is silicon or boron m is 2 to 5 and n is 1 to 3 with m+n=3 to 6 when G is silicon m is 1 to 3 and n is 1 to 3 with m+n=3 to 4 when G is boron and wherein the compound further comprises one or more counterions when the above formula is charged and wherein at least one F is 18F.
