Dodecahedral Octacovalent Bond Orbitals

Abstract

Dodecahedral octacovalent bond orbitals of D2d symmetry are considered. The bond orbitals are divided into two groups which may differ widely in composition, the over-all composition remaining sp3d4. When the average orbital strength is greatest, it equals 2.981 and the orbitals of group one and group two differ in composition and strength. The concept of orbital strength does not allow us to exclude either the dodecahedral or the tetragonal antiprism structure in AB8 when A employs the sp3d4 configuration.

Structure cristalline du tétrakisoxalatohafniate de potassium pentahydraté [K4Hf(C2O4)4.5H2O]

“…On notera la remarquable similitude des configurations moyennes des poly+dres de coordination de ces deux ch61ates. I1 faut bgalement signaler les r6sultats obtenus par Duffey (1950) sur les systbmes MX s dod~ca~driques. Les orbitales du m&al mises en jeu dans les liaisons M-X de type e &ant hybrid+es globalement selon la configuration spad 4, un calcul de l'6nergie de liaison maximale conduit, en particulier, h des valeurs optimales des angles 0 A = 34,33 et 0 B = 72,47 °, qui sont tr+s voisines des valeurs mesur6es dans les deux compos~s consid~r6s ici.…”

“…Ces r6sultats d'ex-p6rience semblent traduire une correlation entre la st~r+ochimie du groupement MO8 et la nature des liaisons M-O. Ainsi, h partir du syst6me d'orbitales construit parDuffey (1950), une augmentation du rapport des distances M-OA/M-O B peut s'expliquer simplement par une contribution accrue des ~lectrons zr aux liaisons du type M-O n, dont la longueur aurait de ce fait tendance ~ diminuer. Toutefois, cette interpr&ation doit &re consid6r6e avec prudence.…”

The Crystal Structure of Zr2(OH)2(SO4)3(H2O)4

“…No correction was applied for the absorption. The scattering curves used in the structure factor calculations were: for Zr that given by Thomas and Umeda,5 for S that given by Tomiie and Siam,6 and for O that given by Berghuis,et at.1 Structure Determination From the data it follows that there are 8 Zr, 12 S, and 72 O atoms in the unit cell. It is unlikely that any of these atoms would occupy a center of symmetry; therefore, only the point positions 4(e) and 8(f) need be considered.…”

Electronic Structure of Octacyanides of Molybdenum IV and V According to the SCCC MO Method. The D2d Case

“…DUF-FEY 13 and RACAH 14 restricted the discussion to pure o bonds. They predicted the antiprism to be more stable than the dodecahedron.…”

“…The earlier theoretical work was mainly concerned with the maximum overlap principle [13][14][15][16] . DUF-FEY 13 and RACAH 14 restricted the discussion to pure o bonds.…”