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We present Raman and infrared absorption data for ${\mathrm{Ba}}_{2}$${\mathrm{YCu}}_{3}$${\mathrm{O}}_{\mathrm{x}}$ with 7&gt;x&gt;6 for several samples with well-characterized oxygen content. Over this range the material has an oxygen-deficient tripled perovskite structure whose superconductivity properties depend critically on x. An orthorhombic-to-tetragonal transition occurs for x\ensuremath{\approxeq}6.5. We have examined both phases for the frequency range \ensuremath{\omega}&gt;400 ${\mathrm{cm}}^{\mathrm{\ensuremath{-}}1}$ which contains the Cu-O bond-stretching vibrations. A force-constant model has been developed which allows us to assign the features in the spectra. Our results are consistent with the linear Cu-O-Cu-O chains in ${\mathrm{Ba}}_{2}$${\mathrm{YCu}}_{3}$${\mathrm{O}}_{7}$ being absent in the nonsuperconducting ${\mathrm{Ba}}_{2}$${\mathrm{YCu}}_{3}$${\mathrm{O}}_{6}$.