Tantalum pentamethoxide

In attempts to prepare tantalum pentaisopropoxide and penta-tm-butoxide by alcoholysis of tantalum pentamethoxide with isopropyl alcohol or tert-butyl alcohol, respectively, Bradley etal could isolate only monomethoxide tetra-isopropoxide or tetra-tert-butoxide ... 

Apart from the monomeric methoxides of the metalloids (B, Si, Ge, As, and Te) which are very volatile and soluble in organic solvents, most of the metal methoxides (except niobium and tantalum pentamethoxides and uranium hexamethoxide) are comparatively nonvolatile and insoluble in common organic solvents. Attempts have been made to... 

The pentavalent niobium and tantalum alkoxides are reasonably volatile and can be distilled unchanged in the pressure range 0.05-10mm, e.g. pentamethoxides of niobium" and tantalum" have been distilled at 153°C/0.1 or 200°C/5.5 and 130°C/0.2 or 189°C/10.0 mm pressures, respectively. The data in Table 2.12 indicate that the boiling points are dependent on chain length furthermore, the methoxides and ethoxides of tantalum are more volatile than the niobium analogues whereas for higher n-alkoxides, the reverse is... 

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