Structures for d0 ML6 and ML5 complexes

Exploring chromium (VI) dioxodihalides chemistry: Is density functional theory the most suitable tool?

“…The theoretical characterization of inorganic compounds is not at all an easy task. [11][12][13][14][15][16][17][18][19][20][21] Thus, whereas the application of mechano-quantum methodology on organic systems has reached a stage not only interpretative but also predictive, 22 transition-metal compounds are more difficult to be described due to four main reasons. First, the quantity of atoms taking part cover practically the whole periodic table.…”

Study of the MAu6 (M: Cr, Mo, W) Molecular Species: A Transition from Halogenlike to Hydrogenlike Chemical Behavior for Gold.

“…While the earliest treatments of WH 6 simply assumed the system to be octahedral 5,6 like the WX 6 hexahalides, it was later discovered that the system strongly distorts to a C 3v structure. 3,[7][8][9] The recent vibrational spectra of WH 6 in a neon matrix verify that C 3v structure. 10,11 Pentamethyltantalum and hexamethyltungsten are distorted like the corresponding hydrides.…”

“…These Group-5 pentahydrides 2-4 and Group-6 hexahydrides [3][4][5][6][7][8][9][10][11] have attracted copious attention. While the earliest treatments of WH 6 simply assumed the system to be octahedral 5,6 like the WX 6 hexahalides, it was later discovered that the system strongly distorts to a C 3v structure.…”

Polymorphism and Structural Distortions of Mixed-Metal Oxide Photocatalysts Constructed with α-U3O8 Types of Layers

“…The PbO7 polyhedra are formed by six apical O atoms and one equatorial O atom (Pb1-O7, Pb2-O9) from the adjacent TaO7 layers that result in the asymmetric coordination environment [35]. Divalent Pb cations commonly undergo intra-polyhedral distortions due to their high degree of polarizability and their stereoactive electron lone pair, and thereby adopt stable asymmetric anion coordination environments (i.e., PbO7) [59,61,[66][67][68]. The stabilization of the Pb(II) cations results in their displacement towards the Ta(V) cations, which in turn electrostatically repulses the Ta atoms (Ta1 and Ta2) from the center of their TaO7 polyhedra towards their apical O atoms [35].…”

“…The symmetry-lowering polar distortions from the centrosymmetric Ag2Ta4O11 3 ) to the noncentrosymmetric PbTa4O11 (R3) space group are characteristic of SOJT distortions that are typically observed for structures with high valent d 0 cations (i.e., Ta(V)) and cations containing filled valence s shells (i.e., Pb(II)). The SOJT distortion reduces the crystal symmetry and is the driving force for stabilizing ionic shifts [59,61,[66][67][68]. …”