The photo- and chemiluminescence of Wohler siloxenes, Si6H3-x(OH)(3+x), in the two oxidation stages with x = 0 : yellow siloxene and x = 1 : red siloxene were studied. During slow oxidation both compounds exhibit a shift of the photoluminescence spectra at room temperature, but the position of the chemiluminescence is not affected. Our results support the bucked-layer structure of Wohler siloxenes with the Si-6-ring in chair conformation as the building block. The Si-H bonds on the ring can be successively oxidized (0 less than or equal to x less than or equal to 3), leading to a shift in the photoluminescence spectrum. Total oxidation of all three Si-H bonds results in an unstable modification, which transforms rapidly to a new substance with distinctively different optical properties. The results on siloxene have common features with measurements on porous silicon. However, the quantitative differences in the spectra indicate that in porous silicon : the emission properties are not directly associated with Wohler siloxenes.