The disilenyl, H 2 SiSiH(X 2 A), and the d3-isotopomer were detected for the first time via infrared spectroscopy in low temperature silane matrices upon an irradiation of the sample matrices with energetic electrons. The ν 5 fundamental was observed at 651 and 493 cm - 1 , respectively. In the d4-silane matrix, the ν 4 at 683 cm - 1 was noticed, too. Our investigations suggest that this radical is formed via radiolysis of silylsilylene, H 3 SiSiH(X 1 A ' ), and disilene, H 2 SiSiH 2 (X 1 A g ). The new absorption of the H 2 SiSiH(X 2 A) radical may be employed in future spectroscopic monitoring of chemical vapor deposition processes and in astronomical searches of silicon-bearing molecules toward the carbon star IRC+10216.