Single crystal X-ray diffraction is used to study the nitrosoruthenium mer-trinitrato complex [RuNO(NH3)2(NO3)3]. The crystallographic data for H6N6O10Ru are as follows: a = 7.6477(1) Å, b = 10.8404(2) Å, c = 24.0168(6) Å, α = β = γ = 90°, V = 1991.09(7) Å3, Z = 8, dcalc = 2/338 g/cm3, space group P212121. The structure is formed of two structurally non-equivalent uncharged mer-[RuNO(NH3)2(NO3)3] complexes. The complex crystallizes as yellow needles or orange powder belonging to the orthorhombic system. The substance is poorly soluble in water, ethanol, and acetone, stable in dark storage. The comparisons with the EXAFS data for this complex and the theoretical DFT calculations with different functionals are performed.