The photoelectron spectrum of 2,4-dichloro-6,7-dithiabicyclo[3.2.1]octane ( ) shows the largest sulfur lone pair energy gap ever observed as a consequence of the cis-disulfide conformation, which has been further studied by molecular mechanics (MMl) and molecular orbital (CNDO/S) calculations of the parent compound, 6,7-dithiabicyclo[3.2.1]octane ( ). ... The β SS ≈ −2.1 eV is the fact identical to the value derived by extra-polation (ref. 8), although it ...