TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Composition: The composition comprises hydrogen and silicon. The hydrogenated semiconductor film has a carbon content and oxygen content of not greater than than 0.1%. Preferred Components: The chain length is an average chain length of 15-1000 silicon and/or germanium units. The Group 7-12 transition metal is: rhodium, ruthenium (both preferred), iron, osmium, cobalt, iridium, nickel, palladium or platinum; and supported on a stationary phase. The catalyst is heterogeneous catalyst and is present at 0.01-10 transition metal atoms to 100 A atoms. In the method (I), the hydrogen-containing compound is (A1). In the method (II), the hydrogen-containing compound is of formula (AaH2a+2). Preferred Method: In method (I), the catalyst removing step comprises filtering the combined catalyst and oligosilane(s) and/or polysilane(s). In method (II), the catalyst removing step comprises: contacting the polysilane or polyarylsilane with an adsorbent or adding a solvent in which the polysilane or polyarylsilane is soluble and the catalyst is insoluble to precipitate the catalyst; and filtering the precipitated catalyst. Preferred Definitions:    A = Si;    n = 3 or 4; and    a = 3-7.    EXAMPLE - Cyclopentasilane (1 g) was added to a amber vial (4 ml) containing 1 mol.% rhodium black (6.9 mg) under an inert atmosphere, and this reaction mixture was allowed to stir for 2 hours in the loosely capped vial. Then, the reaction was quenched with distilled cyclohexane (2 g), and the resulting mixture was transferred to amber vial (equipped with a stir bar) (40 ml) and further diluted with cyclohexane (5 g). After 30 minutes of stirring, insoluble materials were allowed to settle for about 15 minutes, and the mixture was then filtered through a short plug of Celite (RTM: Diatomaceous earth) (primed with distilled cyclohexane). The solution was then transferred to a Schlenk tube and the volatile materials were removed by applying high vacuum for 2 hours to obtain poly(cyclopentasilane) composition (yield 60-70%).