The discoverer Richard R. Schrock considered tantalum to be a metallic phosphorus, and thus tried the use of methyllithium.

[9][10] At room temperature pentamethyltantalum can spontaneously explode, so samples are usually stored in a -20°c freezer.

[10] With many carbon-hydrogen bonds near Ta, analogues of pentamethyltantalum are susceptible to alpha elimination.

[6] Pentamethyltantalum in solution forms stable insoluble complex material when mixed with dmpe (CH3)2PCH2CH2P(CH3)2.

[6] With nitric oxide it gives a white coloured dimer with formula {TaMe3[ON(Me)NO]2}2 (Me=CH3).