Structures of 31 small molecules were modeled at HF6- 31* level and 325 atom-type descriptors of different nature, such as electronegativity, polarizability, energy, charge, density, and steric descriptors, were calculated from molecular formula, optimized geometries, and literature data. The descriptors were employed in PLS ( partial least squares) regression modeling of 59 X1s ( 59 X1s = 1 B1s, 27 C1s, 9 N1s, 14 O1s, and 8 F1s) core-electron binding energies (CEBEs) as unique set and also as elemental sets ( C1s, N1s, O1s, and F1s). Parsimonius PLS models were obtained for all data sets (Q(2) > 0.79, R-2 > 0.84, SEV < 1.10 eV). Exploratory analyses of the PLS data sets have shown that CEBEs possess three-dimensional character which is determined by the element type of the ionized atom, electronegativity character of its chemical environment, and intramolecular stereolectronic effects.175525538