Iron coordination compounds play a vital role in biological systems and most commonly known and studied are the heme proteins and enzymes. The Fe-containing clusters are also involved in catalysis, drug design, and materials science. A new octanuclear iron(III) cluster [Fe8O3(piv)6(mdea)3(thmpH)3]·3Hpiv (1) (Hpiv = pivalic acid) has been prepared by the reaction of a hexanuclear [Fe6(OH)2(piv)12] cluster with tris(hydroxymethyl)propane (thmpH3) and methyldiethanolamine (mdeaH2) ligands in toluene/acetonitrile mixture. Single-crystal X-ray diffraction analysis revealed that compound 1 crystalizes in the monoclinic P21/c space group with unit cell parameters a = 14.6313(5), b = 37.5950(15), c = 23.2333(9) Å, β = 95.521(3)º. The {Fe8} core of 1 consists of two central axial Fe(III) ions that are bridged by three μ4-O with six peripheral Fe(III) ions to form the three blades of the propeller (Figure). These six peripheral Fe(III) ions are noncoplanar and reside in the vertexes of flatten trigonal antiprism. The central pair of iron atoms represents the axis of the propeller with the Fe⋯Fe distance of 2.784(1) Å, while the shortest distances between axial and peripheral iron atoms are in the range 3.009(1)- 3.084(1) Å. Six pivalates, three mdea2− and three thmpH2− completed the coordination spheres of Fe atoms. Axial and peripheral iron atoms display O6 and NO5 distorted octahedral surrounding, respectively. Each of three outer sphere pivalic acid molecules form two hydrogen bonds with thmpH2− ligands.