Single-electron-capture cross sections 10 for W+ projectile ions on Ar and Kr atomic gas targets at 10 keV (55 eV/u) and on H2, D2, CH4, C2H6, and C3H8 molecular gas targets at between 5.0 and 10 keV (27 and 55 eV/u) were experimentally derived for the first time. With our published single-electron-capture cross sections q q-1 for Beq+, Bq+, Cq+ , Feq+ , Niq+ , and Wq+ (q = 1 for Fe; q = 1,2 for the others) ions in low energy, an attempt was made to draw scaling behavior of single-electron-capture cross sections for such slow low-q ions on target species. Established scaling formulas are found to reproduce the measured cross sections generally within a magnitude and with higher precision for specific initial charge state and target species.