Reaction of ZrCl 4 with 2 equiv. of HSnBu 3 followed by addition of phosphines yields hexazirconium cluster compounds [Zr 6 Cl 1 4 H 4 (PR 3 ) 4 ] (2a: PR 3 = PMe 2 Ph; 2b: PR 3 = PEt 2 Pgh; 2c: PR 3 = PEt 3 ) and pentazirconium cluster compounds [Zr 5 Cl 1 2 H 4 (PR 3 ) 5 ] (3a:PR 3 = PMe 2 Ph; 3c; PR 3 = PEt 2 ). Treatment of compound 2a with Na/Hg in the presence of PMe 2 Ph results in the formation [Zr 6 Cl 1 2 H 2 (PMe 2 Ph) 6 ] (4a). When the phosphine ligand is PEt 3 , a similar reaction leads to the isolation of two new cluster compounds, [Zr 6 Cl 1 2 H 3 (PEt 3 ) 6 ][ZrCl 5 (PEt 3 )] (5c) and [Zr 6 Cl 1 3 H 3 (PEt 3 ) 5 ] (6c). In MeCN solution, compound 2a decomposes to form an ionic cluster compound, [HPMe 2 Ph] 4 [Zr 6 Cl 1 8 H 4 ] (7a). Cluster hydrogen atoms were observed by 1 H NMR spectroscopy for all cluster compounds and by X-ray diffraction study for compound 3c where two hydrogen atoms ate μ 3 -bridging and the other two edge-bridging. In compound 7a, there is evidence for the hydrogen atoms distributed near the centers of the one of the eight triangular faces of the Zr 6 octahedron. When ZrCl 4 reacts with 1 equiv. of HSnBu 3 followed by addition of PR 2 Ph, only dinuclear compounds [Zr 2 Cl 4 (μ-Cl) 2 (PR 2 Ph) 4 ] (8a: R = Me; 8b; R = Et) are isolated. All compounds were characterized by X-ray crystallography and 1 H NMR spectroscopy. Compound 2a*d0.75CH 2 Cl 2 crystallized in the monoclinic space group C2/c with cell dimensions (-100 o C) of a = 31.434(9), b = 15.255(6), c = 14.582(8) A, β = 106.08(2) o , V = 6719(9) A 3 and Z = 4. Compound 2b*d2CH 2 Cl 2 crystallized in the monoclinic space group P2 1 /c with cell dimensions (-60 o C) of a = 11.310(1), b = 17.412(5), c = 17.807(2) A, β = 91.55(1) o , V = 3505(1) A 3 and Z = 2. Compound 2c*d2C 6 H 6 crystallized in the monoclinic space group P2 1 /n with cell dimensions (-150 o C of a = 15.322(6), b = 12.186(3), c = 16.969(7) A, β = 91.09(2) o , V = 3117(2) A 3 and Z = 4. Coumpound 2c crystallized in the monoclinic space group C2/c with cell dimensions (-150 o C) of a = 26.128(9), b = 16.826(1), c = 13.411(4) A, β = 117.07(1) o , V = 5250(2) A 3 and Z = 4. Compounds 3c*dC 6 H 5 CH 3 crystallized in the monoclinic space group C2/c with cell dimensions (-75 o C) of a = 48.06(1), b = 12.667(3), c = 22.829(5) A, β = 113.36(2) o , V = 12758(5) A 3 and Z = 8. Compound 4a crystallized in the triclinic space group P1 with cell dimensions (-60 o C) of a = 12.918(3), b = 15.493(2), c = 18.90(1) A, α = 90.31(6), β = 104.37(2), γ = 109.89(3) o , V = 3429(2) A 3 and Z = 2. Compound 5c*d0.5C 6 H 6 crystallized in the monoclinic space group P2/c with cell dimensions (-60 o C) of a = 23.707(6), b = 14.521(2), c = 25.109(3) A, β = 92.08(1) o , V = 8633(3) A 3 and Z = 4. Compound 6c*dC 6 H 6 crystallized in the orthorhombic space group Pna2 t with cell dimensions (-100 o C) of a = 23.496(9), b = 23.973(2), c = 11.638(1) A, V = 6555(3) A 3 and Z = 4. Compound 7a*d2MeCN crystallized in the triclinic space group P1 with cell dimensions (20 o C) of a = 12.881(2), b = 22.859(3), c = 12.208(2) A, α = 98.6614(1), β = 109.99(1), γ = 81.39(1) o , V = 3320.8(9) A 3 and Z = 2. Compounds 8b*d0.67C 6 H 5 CH 3 crystallized in the rhombohedral spacve group r3m with cell dimensions (-100 o C) of a = 20.947(3), b = 20.947(3), c = 30.87(1) A, V = 11730(4) A 3 and Z = 6.