The formation of strong TcN and TcO multiple bonds with one σ and two π components is a characteristic feature of the chemistry of the +5, +6 and +7 oxidation states of the Group 7 transition metal technetium. Simplified group theoretical considerations allow the formal bond order to be determined and provide an explanation for the observed coordination numbers and geometries, the absence of multinitrido species and the structures of d¹and d² μ-oxo dimers. The strong trans influence and effect of the TcN and TcO multiple bonds exert marked structural deformation and chemical reactivity effects. The results of a variety of infrared studies using isotopic Tc¹⁵N substitution and of ¹³CN and C¹⁵N substitution in Cs₂KTcN(CN)₅] are presented and discussed. The electronic spectra of the d¹ [TcNX₄]^- (X = Cl, Br) species are dominated by intense halide- to-metal charge transfer transitions from the halide based donor levels to the singly occupied d_xy HOMO. The differences in the spectra of [TcNX₄]^- in aqueous HX and in organic solvents appear to be due to the presence of [TcN(OH₂)X₄]^- in the aqueous acids.