The structure of trigonal ferrinatrite, Na3Fe(SO4)3⋅3H2O, from the Hongshan Cu-Au deposit, Eastern Tianshan, NW China was refined in space group P $$ \overline{3} $$ based on single crystal X-ray diffraction data [a = 15 .553(2), c = 8.6616(17 ) A, V = 1814.4(5) A3, Z = 6; R1 = 0.0535]. All hydrogen atoms were located by difference Fourier methods and refined with soft restrictions for distances, but with fixed thermal isotropic displacement parameters. The atomic arrangement in ferrinatrite is based on chains along [001] consisting of isolated FeO6-octahedra corner-linked with sulfate groups. All vertices of octahedra link to tetrahedra, and half the tetrahedron vertices link to octahedra. These chains are linked by interstitial Na-ions and H2O groups. All Na atoms are coordinated to four oxygen atoms of sulfate groups and to two oxygen atoms of H2O molecules within 2.33–2.71 A; next oxygens are at distances of 2.85–3.00 A. Among six hydrogen bonds, three acceptor O-atoms of sulfate groups belong to the nearest octahedral-tetrahedral chains, and three acceptor sulfate O-atoms from the neighboring chains, which further strengthen the linkages between octahedral-tetrahedral chains. The O–H···O distances are in the range 2.86–3.13 A. The O–H stretching frequencies derived from structural data are in good consistence with the known Infrared spectra.