Molecular Single‐Bond Covalent Radii for Elements 1–118

Abstract

A self-consistent system of additive covalent radii, R(AB)=r(A) + r(B), is set up for the entire periodic table, Groups 1-18, Z=1-118. The primary bond lengths, R, are taken from experimental or theoretical data corresponding to chosen group valencies. All r(E) values are obtained from the same fit. Both E-E, E-H, and E-CH(3) data are incorporated for most elements, E. Many E-E' data inside the same group are included. For the late main groups, the system is close to that of Pauling. For other elements it is close to the methyl-based one of Suresh and Koga [J. Phys. Chem. A 2001, 105, 5940] and its predecessors. For the diatomic alkalis MM' and halides XX', separate fits give a very high accuracy. These primary data are then absorbed with the rest. The most notable exclusion are the transition-metal halides and chalcogenides which are regarded as partial multiple bonds. Other anomalies include H(2) and F(2). The standard deviation for the 410 included data points is 2.8 pm.

A New Layered Iron Arsenide Superconductor: (Ca,Pr)FeAs2

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“…45 Two extreme, but simple, choices are available: Van der Waals radii 46 (R vdw ) provide an upper limit on the size of an atom and therefore impose significant separations between neighboring adsorbates. Covalent radii 47 (R cov ), on the other hand, provide a lower limit of the size of atoms, which ensures that high coverages are accessible without leading to overlapping patterns. The area of the vertex could be chosen as the Wigner-Seitz cell which is obtained by connecting the midpoints between vertexes by straight lines.…”

Electronic structure theory to decipher the chemical bonding in actinide systems

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