Alkali metal disupersilylsilanides MSiXR* 2 (R*=supersilyl=Si tBu 3; X=H, Me, Ph, F, Cl, Br) are prepared: (i) by metalation of R* 2XSiBr (X=H, Me) with Li, Na or K in heptane, benzene, tetrahydrofuran (THF); (ii) by activated metalation of R* 2SiX 2 with LiC 10H 8 in THF at room temperature (X=F) at −100°C (X=Cl) and at −130°C (X=Br); (iii) by transmetalation between R* 2XSiBr (X=H, Me) and NaR* in THF; (iv) by insertion of the silylene R*PhSi (from R*PhSiHCl and NaR*) into the NaSi-bond of NaR* in THF. The prepared hydrolysis- and oxidation-labile silanides are colorless to yellow, if donorfree, and yellow to deep-red as C 6H 6- or THF-adducts (the C 6H 6-adducts lose the donor in high vacuum, whereas the THF-adducts do not). Due to X-ray structure analyses, the benzene adducts of KSiXR* 2 (X=H, Me) exist as monomers in the crystal with two molecules benzene bound to potassium and an exact planar or a flat pyramidal KSiSi 2 framework in KSiHR* 2 or KSiMeR* 2, respectively. There are contacts of K both to Si and H in KSiHR* 2, but only to Si and not to Me in KSiMeR* 2. Thermolysis of LiSiXR* 2 leads at 25°C (X=F), −78°C (X=Cl) or −120°C (X=Br) to the silylene R* 2Si as reactive intermediate. The silanides MSiXR* 2 (X=H, Me) are strong bases (e.g. deprotonation of C 6H 5CH 3 or SiH 2Cl 2), good nucleophiles (e.g. formation of R* 2XSi–SiF 3 or R* 2XSi–SiH 2Cl with SiF 4 or SiH 2Cl 2), and powerful reduction agents (e.g. conversion of SnCl 2 into Sn).