The four fundamental bands of 70 GeD 4 have been analyzed using the STDS software developed in Dijon (http://www.ubourgogne.fr/LPUB/sTDS.html). Both infrared and Raman spectra were used to observe all fundamental bands. Infrared spectra of monoisotopic 70 GeD 4 were recorded in the regions 600 and 1500 cm -1 using the Bruker 120HR interferometer at Wuppertal. The resolution (1/maximum optical path difference) was between 2.3 and 3.3 × 10 -3 cm -1 for the ν 3 and ν 4 infrared-active fundamental bands as well as for the interacting ν 2 band. A high-resolution stimulated Raman spectrum of the ν 1 band has been recorded in Madrid. The instrumental resolution of the Raman spectrum was 3.3 × 10 -3 cm -1 . We have performed a global fit of the ground state, ν 2 /ν 4 bending dyad, and ν 1 /ν 3 stretching dyad. We have used 1146, 139, and 676 assigned lines for ν 2 /ν 4 , ν 1 , and ν 3 , respectively. The standard deviation is 2.2 × 10 -3 cm -1 for the bending dyad, 1.6 × 10 -3 cm -1 for the ν 3 infrared lines, and 1.7 × 10 -3 cm -1 for the ν 1 Raman lines. These results enabled us to perform the first experimental determination of the equilibrium bond length of germane as r e = 1.5173(1) Å.