The weighted mean and its improved dispersion

E and geometrical structure of neutral and charged iron clusters Fen, Fen, and Fen (n = 2-20) will be discussed. Computational results will be compared to experimental data, in particular, to the recent data obtained from the magnetic moment measurements of Fen +. We consider iron cluster oxides, single Fe atom oxides FeOn for n up to 18, and FeXn superhalogens. We present the results of computational simulations of gas-phase interactions between small iron clusters and OH, N2, CO, NO, O2, and H2O. Competition between surface chemisorption and cage formation in Fe12O12 clusters will be discussed. The magnetic quenching found for Fe12O12 will be qualitatively explained using the natural bond orbital analysis for Fe2O2. Special attention will be paid to the structural patterns of carbon chemisorbed on the surface of a ground-state Fe13 cluster.