There is much current interest in the organometallic chemistry of the f-block elements. Considerable progress has been made in developing the chemistry of the +3[sub la] and 0[sub lb] oxidation states: work on the +2 oxidation state has been mainly concerned with polyhapto ligands, especially substituted cyclopentadienyls. We report the synthesis and crystal structure of bis[l brace]tris-(trimethylsilyl)methyl[r brace] ytterbium, Yb[l brace]C(SiMe[sub 3])[sub 3][r brace][sub 2], obtained in good yield as a highly air- and moisture-sensitive orange solid from the reaction between YbI[sub 2] and K[l brace]C(SiMe[sub 3])[sub 3][r brace][sup 5] in benzene, and the determination of its crystal structure. As far as we are aware this is the first solvent-free dialkyl lanthanide to be characterized. We also describe the preparation and structure of an Yb analogue of a Grignard reagent; these have been used in synthesis but have not previously been isolated. The most interesting and surprising feature of the solid-state structure is that the C-Yb-C angle is 137[degree]. 19 refs., 2 figs.