SS bond distances in S 7 0 2 can be derived using the wave numbers given in Table 1. On the basis of these values, and observations made in structural studies on S80[8a1 and S7018b1, we suggest the following structure for S 7 0 2 (bond lengths in pm): 206 219

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Photoluminescence of sintered zinc orthosilicate doped with Al or Ti has been measured in the temperature range between 20 and 650 K, peak emissions being noted at 407 and 400 nm, respectively. The corresponding excitation spectra show peaks at 218 and 236 nm for Zn2SiO4:normalAl and at 218 and 232 nm for Zn2SiO4:normalTi . The 218 nm peak must be assigned to the excitation of the undoped zinc silicate where doping with Al as well as Ti effects an enhancement of this band. The two phosphors have different decay times at room temperature ( Zn2SiO4:normalAl,t≈10sec ; Zn2SiO4:normalTi,t≈10−3sec ). We observed the greatest quantum efficiency for the u.v.‐blue emission approximately at activator concentrations of 1 mol percent (m/o) Al or 0.6 m/o Ti. Deviations from the linear dependence of the luminescence intensity on the photoexcitation intensity are observed above 400 K.

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Electrical conductivity, photoluminescence, and diffuse reflectance spectra have been measured for the following silversulfamides: O2Sfalse(normalNHAg)2 , O2Sfalse(normalNHAgfalse)false(NAg2false)·NH3·H2O , O2Sfalse(NAg2)2 , and O2Sfalse(NAg2)2·2NH3 . They have been discussed in relation to their crystal structures. With increasing silver content the conductivity increases and the absorption edges of the reflectance spectra are red shifted. The luminescence data have been attributed to centers of the type SNAg2 , SNAg3 , and SNAg4 . Tetrasilversulfamide shows a conductivity increase of about 103 false(=normalΔσ/σ0false) between 365 and 396 K. For trisilversulfamide anisotropy effects have been detected in the photoconductivity measurements.