The thermal and electron activated properties of CCl4 on Si(100), with and without adsorbed hydrogen, have been investigated in the temperature range 100-1100 K using temperature programmed desorption (TPD), electron stimulated desorption, and x-ray photoelectron spectroscopy. Dosed at 100 K but not exposed to electrons, molecular CCl4 desorbs from both surfaces between 120 and 170 K with coverage-dependent monolayer and multilayer peaks. An etching product, SiCl2 desorbs from Si(100), but not H-Si(100). Electron irradiation of CCl4 on both surfaces at 100 K drives : reactions with ejection and retention of products. Compared to thermal activation, SiCl2 TPD is enhanced on Si(100), while on H-Si(100), the SiCl2 TPD channel opens and HCl peaks appear at 610 and 820 K in TPD. Ejection of neutral CClx (x less than or equal to 4) and Cl is observed on both Si(100) and H-Si(100), and the CCl+ ion signal decays with a cross section of (1.3 +/-0.1) x 10(-16) on Si(100) and (2.8 +/- 0.5) x 10(-17) cm(2) on H-Si(100). On both surfaces, the electron activated cross section describing the decay of the CCl4 TPD peak area is 9 x 10(-17) cm(2). C2Clx (x = 2, 4, and 6) appear in post-irradiation TPD.