The variations of the crystal structures and thermoelectric properties of the Ru1-xRexSiy
chimney-ladder phases were studied as a function of the Re concentration. A series of chimney-ladder
phases with a compositional formula of Ru1-xRexSi1.539+0.178x are formed in a wide compositional
range, 0.14 ≤ x ≤ 0.76. The composition of the chimney-ladder phase is systematically deviated from
the idealized composition satisfying the valence electron concentration rule: VEC=14. Measurements
of thermoelectric properties reveal that the chimney-ladder phases exhibit n-type semiconducting
behavior at low Re concentrations and p-type semiconducting behavior at high Re concentrations,
which are well consistent with the prediction based on the deviation of the composition of the
chimney-ladder phase from the idealized composition.