SAXS data from solutions of A and C rich mixed sequence single stranded RNA in 100 mM NaCl, 10 mM MOPS, 20 µM EDTA, pH 7 were collected using a Xenocs BioXolver L with GeniX3D instrument (University of Copenhagen, Department of Drug Design and Pharmacology) equipped with a Pilatus3 R 300K detector at a sample-detector distance of 0.7 m and at a wavelength of λ = 0.154189 nm (I(s) vs s, where s = 4πsinθ/λ, and 2θ is the scattering angle). Solute concentrations ranging between 1 and 2.9 mg/ml were measured at 25°C. 10 successive 120 second frames were collected. The data were normalized to the intensity of the transmitted beam and radially averaged; the scattering of the solvent-blank was subtracted. The low angle data collected at lower concentrations were extrapolated to infinite dilution and merged with the higher concentration data to yield the final composite scattering curve.