Which compound has highest SRP (standard reduction potential) value, e.g. the strongest oxidising agent? In most tables $\ce{F2}$ is at top with $E^\circ = \pu{2.87 V}$, but I've found a table listing $\ce{H4XeO6}$ at top with $E^\circ = \pu{3.0 V}$.
Is there a more strongest oxidising agent on basis of $E^\circ$ value and is $E^\circ$ value defined for every compound? If yes, what is $E^\circ$ value for $\ce{ClF3}$?
Top 5 oxidants from the CRC Handbook of Chemistry and Physics [1, p. 5-83]:
TABLE 2. Reduction Reactions Having $E^\circ$ Values More Positive Than That of the Standard Hydrogen Electrode
$$ \begin{array}{ll} \hline \text{Reaction} & E^\circ/\pu{V}\\ \hline \ce{F2 + 2 H+ + 2 e- ⇌ 2 HF} & 3.053\\ \ce{Tb^4+ + e- ⇌ Tb^3+} & 3.1\\ \ce{Pr^4+ + e- ⇌ Pr^3+} & 3.2\\ \ce{Cf^4+ + e- ⇌ Cf^3+} & 3.3\\ \ce{XeF + e- ⇌ Xe + F-} & 3.4\\ \end{array} $$
Note that standard reduction potential is not characteristic for a single compound. Instead, it is only makes sense for a given redox pair – of course, assuming standard conditions ($\pu{298.15 K}$, $\ce{101.325 kPa}$), activity of all soluble species $\pu{1 .000 mol L-1}$ and measured against the standard hydrogen electrode.
For example, iodate $\ce{IO3-}$ has very rich redox chemistry and many SRP values [1, p. 5-79]:
$$ \begin{array}{ll} \hline \text{Reaction} & E^\circ/\pu{V}\\ \hline \ce{2 IO3– + 12 H+ + 10 e- ⇌ I2 + 6 H2O} &1.195\\ \ce{IO3– + 6 H+ + 6 e- ⇌ I– + 3 H2O} &1.085\\ \ce{IO3– + 2 H2O + 4 e- ⇌ IO– + 4 OH–} &0.15\\ \ce{IO3– + 3 H2O + 6 e- ⇌ IO– + 6 OH–}& 0.26\\ \end{array} $$
