  In many astrophysical objects an account for scattering of the X-ray
fluorescent and resonance lines of iron ions by the electrons, bound in atomic
and molecular hydrogen is important. Specific distortions of the scattered line
profile spectrum appear in comparison with scattering by free electrons.
Analysis of scattered line spectra may provide information on the ionization
state, helium abundance and geometry of scattering media in the vicinity of
AGNs, compact X-ray sources and on the surface of X-ray flaring stars and the
Sun.
