Solution X-ray scattering is a powerful tool to understand conformations of macromolecules in vitro.Small-angle X-ray scattering (SAXS) provides low-resolution (20 - 100 Angstrom) envelope of electron densities while wide-angle X-ray scattering (WAXS) reveals finer structural information beyond the SAXS resolution. Ribonucleic acids (RNAs), with important biological functions, exhibit both large-scale molecular arrangements and fine structural periodicity, which are revealed by SAXS and WAXS. Qualitative macromolecular behaviors can be inferred by RNA construct design and comparison of X-ray scattering profiles. However, molecular and statistical modeling of experimental SAXS or WAXS profiles is required for a quantitative interpretation on the RNA system of interest. In this work, we started by applying ab initio reconstruction and refining atomic molecular models generated by molecular dynamics (MD) simulations using experimental SAXS profiles to investigate the ion-dependent role of RNA junctions in determining the overall conformations. Furthermore, we extended both ideas to the wide-angle regime to reveal much finer structural variations that is invisible to the SAXS experiments. Our methods as well as the understanding of ion-dependent RNA behaviors are significant to the solution X-ray scattering and RNA communities.