The new molecules P3RhMe3-n (OTf) n are reported (n = 0−2; P3 = MeC(CH2PMe2)3; OTf = OS(O)2CF3). The known fac-(Me3P)3RhMe3 was converted to mer-(Me3P)3RhMe3-n Cl n (n = 1, 2) by cleavage with HCl in ether. X-ray photoelectron spectra (XPS) of these were recorded, and all except the P3RhMe3-n Cl n series afforded clean spectra. XPS were also obtained for the known CnRhMe3-n X n (n = 0−2; X = Cl, Br, OTf; Cn = 1,4,7-trimethyl-1,4,7-triazacyclononane), CnRhX3 (X = Cl, Br), CnRhMe(OH)(OTf), and [CnRhMe2(CO)]OTf. An X-ray crystal structure of P3RhMe3 is reported, and the geometry at the metal is compared among P3RhMe3, (Me3P)3RhMe3, and CnRhMe3. Core binding energies (BEs) for the series L3RhMe3-n X n (L3 = Cn, P3) change linearly with n for a given L3 and X. For CnRhMe3-n X n , replacement of methyl by chloride or bromide gives similar ΔBE values (∼0.7 eV), while triflate-for-methyl substitution gives a much larger ΔBE (1.2 eV). Triflate-for-methyl substitution in P3RhMe3-n (OTf) n , however, causes a ΔBE of only 0.8 eV. Thus, the Rh(3d5/2) core binding energies in these complexes change less in triflate-for-methyl substitutions when the P3 ancillary ligand is present than in the presence of Cn; apparently P3 compensates for changes in electron density at the rhodium center more effectively than does Cn, presumably as a result of the greater polarizability of phosphorus (softer) compared to nitrogen (harder). The XPS trends for these series effectively mean that P3 makes RhIII a softer metal and Cn makes RhIII a harder metal.