  We show how the presence of inversion symmetry in a one-dimensional (1D)
lattice model is not a sufficient condition for a quantized Zak's phase. This
is only the case when the inversion axis is at the center of the unit cell.
When the inversion axis is not at the center, the modified inversion operator
within the unit cell gains a k-dependence in some of its matrix elements which
adds a correction term to the usual Zak's phase expression1, making it in
general deviate from its quantized value. A general expression that recovers a
quantized Zak's phase in a lattice model with a unit cell of arbitrary size and
arbitrarily positioned inversion axis is provided in this paper, which relates
the quantized value with the eigenvalues of a modified parity operator at the
inversion invariant momenta.
