AbstractA recently developedab initiopseudopotential molecular orbital approach was applied to the Te 42+ion, a system outside the practical reach of conventional all‐electron treatments. Computations were carried out with a minimalSTO‐4G basis set. Results account reasonably well for the observed optical absorption spectrum and suggest the origin of a hitherto unassigned weak band. Ground‐state properties, which included the structure, force field, and vibrational frequencies, were also investigated. Treated as a free, gas‐phase ion, tetratellurium (II) yielded a bond length 0.05 Å shorter than the experimental value for the ion in a crystal lattice. Placement of static, point‐charge counterions in the Te 42+coordination sphere increased the bond length to a value 0.005 Å longer than derived by experiment. Calculations on neutral, cyclic Te4provided a theoretical single‐bond reference length 0.09 Å longer than that obtained for the ion in a counterion environment. Comparisons between observed and calculated frequencies suggest an assignment of the vibrational spectrum different from the provisional assignment