The Synthesis of Atoms, the Whole Number Rule, and the Periodic System of the Atomic Species.

1929 ◽  
Vol 5 (4) ◽  
pp. 371-435 ◽  
Author(s):  
William D. Harkins
Keyword(s):  
Periodic System ◽  
Whole Number ◽  
Atomic Species

Influence of polyhedron distortions on calculated bond-valence sums for cations with one lone electron pair

2007 ◽  
Vol 63 (2) ◽  
pp. 216-228 ◽  
Author(s):  
X. Wang ◽  
F. Liebau
Keyword(s):  
Periodic System ◽  
Lone Electron Pair ◽  
Electron Pair ◽  
Bond Valence ◽  
Correlation Equations ◽  
Coordination Polyhedra ◽  
Absolute Value ◽  
Whole Number ◽  
Correlation Parameters ◽  
Bond Valence Model

In the present bond-valence model (BVM), the bond-valence parameters r 0 and b are, in general, supposed to be constant for each A–X pair and equal to 0.37 Å for all A–X pairs, respectively. For [A i (X j ) n ] coordination polyhedra that do not deviate strongly from regularity, these suppositions are well fulfilled and calculated values for the bond-valence sums (BVS) i are nearly equal to the whole-number values of the stoichiometric valence. However, application of the BVM to 2591 [L i (X j ) n ] polyhedra, where L are p-block cations, i.e. cations of the 13th to 17th group of the periodic system of elements, with one lone electron pair and X = O−II, S−II and Se−II, shows that r 0i values of individual [LX n ] polyhedra are correlated with the absolute value |Φ i | of an eccentricity parameter, Φ i , which is higher for more distorted [LX n ] polyhedra. As a consequence, calculated (BVS) i values for these polyhedra are also correlated with |Φ i |, rather than being numerically equal to the stoichiometric valence of L. This is interpreted as the stereochemical influence of the lone electron pair of L. It is shown that the values of the correlation parameters and the R 2 values of the correlation equations depend on the position of the L cation in the periodic system of elements, if the correlations are assumed to be linear. This observation suggests that (BVS) L describes a chemical quantity that is different from the stoichiometric valence of L.

Study of charge transfer in FeTi

1983 ◽  
Vol 41 ◽  
pp. 296-297
Author(s):  
J. Taft∅
Keyword(s):  
Charge Transfer ◽  
Charge Distribution ◽  
Electron Scattering ◽  
Periodic System ◽  
Electron Distribution ◽  
Scattering Amplitude ◽  
Transition Elements ◽  
Hartree Fock ◽  
Cscl Structure ◽  
The Right

It is well known that for reflections corresponding to large interplanar spacings (i.e., sin θ/λ small), the electron scattering amplitude, f, is sensitive to the ionicity and to the charge distribution around the atoms. We have used this in order to obtain information about the charge distribution in FeTi, which is a candidate for storage of hydrogen. Our goal is to study the changes in electron distribution in the presence of hydrogen, and also the ionicity of hydrogen in metals, but so far our study has been limited to pure FeTi. FeTi has the CsCl structure and thus Fe and Ti scatter with a phase difference of π into the 100-ref lections. Because Fe (Z = 26) is higher in the periodic system than Ti (Z = 22), an immediate “guess” would be that Fe has a larger scattering amplitude than Ti. However, relativistic Hartree-Fock calculations show that the opposite is the case for the 100-reflection. An explanation for this may be sought in the stronger localization of the d-electrons of the first row transition elements when moving to the right in the periodic table. The tabulated difference between fTi (100) and ffe (100) is small, however, and based on the values of the scattering amplitude for isolated atoms, the kinematical intensity of the 100-reflection is only 5.10-4 of the intensity of the 200-reflection.

Element 103 of the periodic system

1968 ◽  
Vol 14 (3) ◽  
pp. 331-339 ◽  
Author(s):  
E. D. Donets ◽  
V. A. Druin ◽  
V. L. Mikheev
Keyword(s):  
Periodic System

The stability of heavy nuclei and the limit of the periodic system of elements

1970 ◽  
Vol 100 (1) ◽  
pp. 45-92 ◽  
Author(s):  
G.N. Flerov ◽  
V.A. Druin ◽  
A.A. Pleve
Keyword(s):  
Periodic System ◽  
Heavy Nuclei ◽  
The Stability

17O, 13C, and 29Si NMR spectra of some acyloxy- and diacetoxysilanes and acetoxygermanes

1986 ◽  
Vol 51 (11) ◽  
pp. 2582-2589 ◽  
Author(s):  
Antonín Lyčka ◽  
Jaroslav Holeček ◽  
Karel Handlíř ◽  
Josef Pola ◽  
Václav Chvalovský
Keyword(s):  
Periodic System ◽  
Time Scale ◽  
Nmr Spectra ◽  
Group Element ◽  
29Si Nmr ◽  
Carboxyl Group ◽  
29Si Nmr Spectra ◽  
Oxygen Atoms

The 17O, 13C, and 29Si NMR spectra of (CH3)3SiOC(O)R, CH3(XCH2)Si(OC(O)CH3)2, and R3GeOC(O)CH3 compounds are reported. In the 17O NMR spectra at 350 K the only signal is observed with the two latter series, but two well-resolved signals are displayed with the (CH3)3SiOC(O)R compounds. The equivalence of both oxygen atoms in carboxyl group on the NMR time scale is discussed from the viewpoint of a possible coordination of the oxygen atoms to the IVB group element of the periodic system.

scholarly journals Linear Time-Periodic System Identification with Grouped Atomic Norm Regularization

2020 ◽  
Vol 53 (2) ◽  
pp. 1237-1242
Author(s):  
Mingzhou Yin ◽  
Andrea Iannelli ◽  
Mohammad Khosravi ◽  
Anilkumar Parsi ◽  
Roy S. Smith
Keyword(s):  
System Identification ◽  
Periodic System ◽  
Linear Time ◽  
Atomic Norm ◽  
Time Periodic
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