  The phase diagram of the copper-oxide chain as a function of density and the
nearest-neighbour Coulomb interaction, V, is determined. Phase separation takes
place above a critical value of $V$ when the Cu2+ to Cu+ valence fluctuations
dominate. In the proximity of the phase separation boundary the superconducting
correlations are the most divergent. We identify the parameter regions where
the Luttinger Liquid theory applies and calculate the contours of the
charge-charge correlation exponent K_{\rho}. We show that anomalous flux
quantization occurs as K_{\rho} diverges. At n = 1, for V > t, a gap opens in
the spectrum and the ground state is a charge-density wave.
