The Stereochemistry of Coördination Number Eight. Isomers for the Trigonal Prism with Symmetry C2v

1943 ◽  
Vol 65 (11) ◽  
pp. 2257-2258
Author(s):  
Louis E. Marchi
2014 ◽  
Vol 70 (4) ◽  
pp. m124-m124 ◽  
Author(s):  
Mingqiang Hu ◽  
Chengbing Ma ◽  
Huimin Wen ◽  
Honghua Cui ◽  
Changneng Chen

The trinuclear title compound, [Fe3(C3H6S2)2(CO)7], is a mixed-valent FeI/FeIIcomplex and crystallizes with two molecules of similar configuration in the asymmetric unit. The three Fe atoms in each molecule display a bent arrangement [Fe—Fe—Fe = 156.22 (4) and 157.06 (3)°]. Both outer FeIatoms are six-coordinated in a distorted ocahedral coordination geometry defined by the bridging FeIIatom, three carbonyl C atoms and two bridging S atoms. The coordination number of the central FeIIatom is seven and includes bonding to the two outer FeIatoms, four bridging S atoms and one carbonyl C atom. The resulting coordination polyhedron might be described as a highly distorted monocapped trigonal prism. In the crystal packing, the molecules exhibit a chain-like arrangement parallel to [100] and [001], and the resulting layers are stacked along [010]. The cohesion of the structure is dominated by van der Waals interactions.


Author(s):  
Carsten Jenne ◽  
Valentin van Lessen

In the title compound, Na+[Me3NB12Cl11]−·SO2 [systematic name: sodium 1-(trimethylammonio)undecachloro-closo-dodecaborate sulfur dioxide], the SO2 molecule is η 1-O-coordinated to the Na+ cation. Surprisingly, the SO2 molecule is more weakly bound to sodium than is found in other sodium–SO2 complexes and the SO2 molecule is essentially undistorted compared to the structure of free SO2. The Na+ cation has a coordination number of eight in a distorted twofold-capped trigonal prism and makes contacts to three individual boron cluster anions, resulting in an overall three-dimensional network. Although the number of known η 1-O-coordinated SO2 complexes is growing, sodium-SO2 complexes are still rare.


2017 ◽  
Author(s):  
Olivier Charles Gagné

Bond-length distributions have been examined for eighty-four configurations of the lanthanide ions and twenty-two configurations of the actinide ions bonded to oxygen. The lanthanide contraction for the trivalent lanthanide ions bonded to O<sup>2-</sup> is shown to vary as a function of coordination number and to diminish in scale with increasing coordination number.


Soft Matter ◽  
2021 ◽  
Author(s):  
D. Zeb Rocklin ◽  
Lilian C Hsiao ◽  
Megan E Szakasits ◽  
Michael J Solomon ◽  
Xiaoming Mao

Rheological measurements of model colloidal gels reveal that large variations in the shear moduli as colloidal volume-fraction changes are not reflected by simple structural parameters such as the coordination number,...


2021 ◽  
Vol 7 (6) ◽  
pp. 77
Author(s):  
Bin Zhang ◽  
Yan Zhang ◽  
Guangcai Chang ◽  
Zheming Wang ◽  
Daoben Zhu

Crystal-to-crystal transformation is a path to obtain crystals with different crystal structures and physical properties. K2[Co(C2O4)2(H2O)2]·4H2O (1) is obtained from K2C2O4·2H2O, CoCl2·6H2O in H2O with a yield of 60%. It is crystallized in the triclinic with space group P1 and cell parameters: a = 7.684(1) Å, b = 9.011(1) Å, c = 10.874(1) Å, α = 72.151(2)°, β = 70.278(2)°, γ = 80.430(2)°, V = 670.0(1) Å3, Z = 2 at 100 K. 1 is composed of K+, mononuclear anion [Co(C2O4)2(H2O)22−] and H2O. Co2+ is coordinated by two bidentated oxalate anion and two H2O in an octahedron environment. There is a hydrogen bond between mononuclear anion [Co(C2O4)2(H2O)22−] and H2O. K2[Co(μ-C2O4)(C2O4)] (2) is obtained from 1 by dehydration. The cell parameters of 2 are a = 8.460(5) Å, b = 6.906 (4) Å, c = 14.657(8) Å, β = 93.11(1)°, V = 855.0(8) Å3 at 100 K, with space group in P2/c. It is composed of K+ and zigzag [Co(μ-C2O4)(C2O42−]n chain. Co2+ is coordinated by two bisbendentate oxalate and one bidentated oxalate anion in trigonal-prism. 1 is an antiferromagnetic molecular crystal. The antiferromagnetic ordering at 8.2 K is observed in 2.


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