  The electric hyperfine interaction observable in atomic spectroscopy for O
and Cu ions in various configurations is used to analyze the quadrupole
splitting of O and Cu nuclear magnetic resonance (NMR) in La2-xSrxCuO4 and
YBa2Cu3O6+y and to determine the hole densities at both sites as a function of
doping. It is found that in La2-xSrxCuO4 all doped holes (x) reside in the Cu-O
plane but almost exclusively at O. For YBa2Cu3O6+y and y<0.6 doped holes are
found at planar Cu as well as O. For y>0.6 further doping increases the hole
content only for planar O. The phase diagram based on NMR data is presented.
Further implications from the Cu A and B site in La2-xSrxCuO4 and the two
planar O sites in YBa2Cu3O6+y and consequences for the phase diagram are
discussed.
