Organolanthanide chloride complexes [(CH3OCH2CH2C5H4)2Ln(mu-Cl)]2 (Ln = La, Pr, Ho and Y) react with excess NaH in THF at 45-degrees-C to give the dimeric hydride complexes [(CH30CH2CH2C5H4)2Ln(mu-H)]2, Which have been characterized by IR, H-1 NMR, MS and XPS spectroscopy, elemental analyses and X-ray crystallography. [CH3OCH2CH2C5H4)2Y(mu-H)2 crystallizes from THF/n-hexane at -30-degrees-C, in the triclinic space group P1 with a = 8.795(2) angstrom, b = 11.040(1) angstrom, c = 16.602(2) angstrom, alpha = 93.73(1)degrees, beta = 91.82(1), gamma = 94.21(1), D(c) = 1.393 gcm-3 for Z = 2 dimers. However, crystals Of [(CH3OCH2CH2C5H4)2Ho(mu-OH)]2 were obtained by recrystallization of holmium hydride in THF/n-hexane at -30-degrees-C, in the orthorhombic space group Pbca with a = 11.217(2) angstrom, b = 15.865(7) angstrom, c = 17.608(4) angstrom, D(c) = 1.816 gcm-3 for Z = 4 dimers. In the complexes of yttrium and holmium, each Ln atom of the dimers is coordinated by two substituted cyclopentadienyl ligands, one oxygen atom and two hydrogen atoms (for the Y atom) or two hydroxyl groups (for the Ho atom) to form a distorted trigonal bipyramid if the C(eta5)-bonded cyclopentadienyl is regarded as occupying a single polyhedral vertex.