Structure of the Alkali Hydroxides. III. Microwave Spectra of RbOH and RbOD

The microwave spectra of gaseous RbOH and RbOD have been measured with a high‐temperature spectrometer. The spectra are generally similar to those observed in CsOH and indicate an essentially linear structure for rubidium hydroxide. The variation of rotational constant with excitation of the bending mode shows anomalies similar to those found in CsOH. The Rb–O bond length is found to be 2.30₅ Å, while the O–H distance is 0.96₅ Å. Analysis of the nuclear quadrupole hyperfine structure gives $\mathrm{eqQ}$ values of − 67.9 Mc/sec in ⁸⁵RbOH and − 35 Mc/sec in ⁸⁷RbOH.