Gas-phase lanthanide chloride clusters: relationships among ESI abundances and DFT structures and energeticsElectronic supplementary information (ESI) available: Mass spectra of LnCl3 (Ln = La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu), LnBr3 (Ln = La, Ce, Pr, Nd, Sm, Lu), and LnI3 (Ln = La, Lu). Mass spectra of diluted LaCl3 and LuCl3 solutions, and of solutions with an excess of chloride. Geometrical structures of high-energy isomers of La2Cl7 and Lu2Cl7, different views of La6Cl19,

Anionic lanthanide chloride clusters, Ln n Cl 3 n +1 , were produced by electrospray ionization (ESI) of LnCl 3 in isopropanol, where Ln = LaLu (except Pm); the clusters were characterized using a quadrupole ion trap mass spectrometer. High-abundance magic number clusters were apparent at n = 4 for the early Ln (LaSm), and at n = 5 for the late Ln (DyLu). Density functional theory computations of La n Cl 3 n +1 and Lu n Cl 3 n +1 clusters ( n = 16) indicate that the clusters with n = 46 are rings with a central chlorine atom. Computed structures show six-coordinate Ln in distorted octahedral sites in magic number La 4 Cl 13 and Lu 5 Cl 16 , which have particularly large dissociation energies. For lanthanum, larger anionic chloride clusters with multiple charges of down to 5 were observed; their fragmentation by collision-induced dissociation in the ion trap revealed La 4 Cl 13 as a common product. Gas-phase hydrolysis to Ln n Cl 3 n +1 y (OH) y ( y = 1, 2) was prevalent for the late lanthanides, but only for small clusters, n = 2 or 3; larger clusters were evidently resistant to gas-phase hydrolysis. ESI of selected LnBr 3 and LnI 3 resulted in Ln n X 3 n +1 clusters (X = Br, I)in contrast to Ln n Cl 3 n +1 clusters, the only observed (minor) high-abundance clusters were La 4 Br 13 and Ce 4 Br 13 . Structures and stabilities of trivalent lanthanide chloride anion clusters, Ln n Cl 3 n +1 , are influenced by the Ln contraction, and preferential Ln coordination in distorted octahedral sites.