The novel mixed-valence alkoxide [EU3+E-4 U-2+O(OPri)(12)(HOPri)]*HOPri (1) has been prepared and structurally and spectroscopically characterized. The three synthesis routes (i) metathesis of 4EuCl(3), Eul(2), and 14KOPr(i) combined with hydrolysis with 1H(2)O, (i) oxidation of 5[EU4(OPri)(10)(HOPi)(3)]*2NHOPr(i) with 1.5O(2), and (III) reduction of EU5O(OPri)(13) with 0.8[Eu-4((OPri)jo(HOPri)3J*2HOPri all yielded pure 1, whereas (iv) reduction of Eu5O(OPri)13 with 0.360 - 0.5 mol of europium metal produced impure 1. The compound, having the average Eu oxidation number +2.8, is very sensitive toward further oxidation to Eu5O(OPri)13 and is part of a redox series of europium 2-propoxides with average oxidation states +2.5, +2.8, and +3. The square pyramidal molecular structure, containing an oxo-oxygen atom in the basal plane, is similar to that of the well-known Ln(5)O(OPri)(13); the main difference is the substitution of an (Eu3+-OPri) pair for an (Eu2+-HOPri) pair in the basal plane. Fourier transform infrared (FT-IR) and UV-visible spectroscopy showed that the solid-state structure was retained on dissolution in hexane and toluene-HOPri. The compound was further characterized by differential scanning calorimetry and solubility studies.