Crystals space group

It is often difficult to represent inorganic compounds with the usual structure models because these structures are based on complex crystals space groups), aggregates, or metal lattices. Therefore, these compounds are represented by individual polyhedral coordination of the ligands such as the octahedron or tetrahedron Figure 2-124d). 

X-ray structures of mitochondrial 6ci complexes from three different sources (113, 124, 125) have found the b- and c-type hemes at roughly identical positions, whereas the Rieske protein was seen in different places as a function of crystal space group and presence or absence of inhibitors of the enzyme. This fact was interpreted to suggest a long-range conformational movement of the Rieske protein during turnover of the complex. The range of observed positions of the Rieske protein indicated that the soluble domain can move like a... 

Fast methods for evaluating these integrals for the case of gaussian basis functions are known [12], Also, Hall has described how to get the symmetry operators (B) 1SjB, r, for any crystal space group [13]. The parameters account for thermal smearing of the charge density. In this work I use the form recommended by Stewart [14],... 

Species, Crystal Space Group, Resolution A) H2O ID (watxxx) H-Bond Partner— H2O Distance (A)... 

It has been earlier mentioned that the octacoordinated Pr(III) ion in triclinic NH4[Pr(TTA)4] -HaO crystal (space group Z = 2) possesses essentially... 

Table 16.1 Representative crystal space group analysis viruses versus proteins...

The structure of pseudoazurin from A. faecalis strain S-6 was determined in two laboratories (in part, because it crystallizes so readily excellent crystals are formed in a matter of hours ) (Petratos et al., 1987, 1988a Adman et al, 1989). The crystals, space group P6j, have the interesting property that they are intensely blue when viewed along the sixfold axis, but are nearly colorless when viewed normal to this axis. This is assumed to be due to the fact that the plane of the Cu-Sy-C/3 atoms is perpendicular to the sixfold axis, consistent with the fact that the copper— thiolate bond is responsible for the blue color of the protein. 

N-(2-acetamido-4-nitropheryl)pyrrolidene (PAN) is dimorphic. The thermodynamically stable form is non-polar (Fig.2), (14). The crystal space group is P21 with two independent molecules per asymmetric unit which are related by a pseudo center of inversion. This crystal does not display measurable frequency doubling generation. 

The crystal structure analysis (by two-dimensional Fourier methods) was facilitated by the fact that the crystal space group requires the molecule to have symmetry 222, the asymmetric crystal unit consisting of one-quarter of the chemical molecule. If there were no distortions from a regular planar model with a trigonal arrangement of bonds... 

The parameter Z is used to denote the number of molecules or formula units in the asymmetric unit of a crystal structure, i.e. the number of molecules that cannot be related to one another by the symmetry operations defined by the crystal space group. Of course, Z is therefore crucially dependent on the somewhat subjective definition of what constitutes the formula unit . Strictly Z is defined as the number of formula units in the unit cell divided by the number of independent general positions. The... 

Crystallisation of racemic 9 from a variety of solvents results in penannular inclusion compounds where two molecules of the host wrap round one of the guest [30], The resulting molecular pens assemble as layers by means of aryl offset face-face (OFF) interactions (Section 3.1.2). The crystal space groups observed are usually P2i/c, and sometimes C2/c. 

Crystal Space group Number of d electrons Ligand field 1 Reference... 

Subsequently, however, the carbohydrate-specific binding site has been identified in crystals grown from the Con A—aMeMan complex(4). Growth of these crystals (space group C222,) was preceded by incubation of Con A with a large excess of aMeMan. The three-dimensional structure was solved at 6 A... 

Literature reports of crystal space groups of triboluminescent materials provide evidence for a modest correlation between tribo-luminescence and noncentric space group Q5) of 36 triboluminescent inorganic sulfates (16), 21 are noncentric and 15 are centric of 19 triboluminescent aromatic organic crystals (12) of known crystal structure, 13 are noncentric and 6 are centric. Many compounds crystallize in more than one space group thus the literature crystal structures may not be relevant to the triboluminescent materials. We therefore examined samples from the same batch of crystals for triboluminescence activity and crystal structure. The results are shown in Table II, along with some related compounds (6, 12, 13) whose crystal structures were obtained from the literature. 

Fulleride K3C60 is a face-centered cubic crystal, space group Fm3m, with a = 1424(1) pm and Z = 4. The C603- ions form a ccp structure with K+ ions filling all the tetrahedral interstices (radius 112 pm) and octahedral interstices (radius 206 pm), as shown in Fig. 14.2.8. 

The magnetic susceptibility which can be calculated through (1) is the molecular susceptibility while the one which can be experimentally measured is the crystal susceptibility the two are identical only when the site symmetry of the metal ion is equal to the point symmetry of the crystal space group. When the site symmetry is lower the molecular susceptibility can be obtained only through some indirect procedure39. ... 

Figure 1 Three line-position and line intensity roadmaps as a function of rotation angle (deg), for rotations about three orthogonal rotation axes, obtained from solid-state 31P cross-polarization (CP) NMR spectra at fixed magnetic fields of 4.7 T, for single-crystals (space group C2/m) of TMPS (tetramethyldiphosphine sulfide). One sees the spectra from two site types occurring in abundance ratio 1 2, each with a spin-spin doublet structure. Taken from Ref. 31.

Diffraction Pattern Symmetry and Crystal Space Group... 

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