# Why can we extract the oxidation state from XPS and XANES but not from XRF or EDX?

To my understanding it is possible to extract information about the valence/oxidation state of an ion in a material by using X-ray photoelectron spectroscopy (XPS) or X-ray absorption near edge spectroscopy (XANES).

However it's only possible to do element identification (without any knowledge about the oxidation state) with X-ray fluorescence (XRF) or energy-dispersive X-ray spectroscopy (EDX).

My question is: What's the difference between these two sets of techniques when it comes down to determining the oxidation state of ions in the specimen under consideration?

In principle, EDX can also measure the oxidation state of a compound, but the difference between XPS and EDX comes down to the energy $\textit{resolution}$ of the detectors in each case. EDX detects X-rays from higher level shell electrons falling into core electron shells after an electron beam has knocked out the core electron. XPS measure the kinetic energy of a core electron that has been knocked out by and X-ray