The disilenyl, H2SiSiH(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 v(5) fundamental was observed at 651 and 493 cm(-1), respectively. In the d4-silane matrix, the v(4) at 683 cm(-1) was noticed, too. Our investigations suggest that this radical is formed via radiolysis of silylsilylene, H3SiSiH(X(1)A'), and disilene, H2SiSiH2(X(1)A(g)). The new absorption of the H2SiSiH(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. (C) 2004 Elsevier B.V. All rights reserved.