P2 2 2 space group

Ohashi also reported the asymmetric induction by the irradiation of chiral crystals of achiral (2-cyanoethyl)(pyrrolidine)cobaloxime complex 62. [37] In this case, the achiral cobaloxime complex crystallized in P2 2 2 space group, and the solid-state photolysis... 

Figure 10 Experimental NRVS spectra of polycrystalUne (powder, D (v)) and single crystal (in-plane, (5) and out-of-plane, (v)) [Fe(TPP)(l-MeIm)(NO)]. Due to porphyrin packing in the P2 2 2 space group, the in-plane orientation orients all porphyrin planes 13.8° from the incident beam. The out-of-plane orientation obtained by rotation of the crystal by 90° orients all porphyrin normals to within 13.8°...

The polymorphic forms of L-histidine are known as A-histidine and B-histidine. The crystal structures of both A-histidine (orthorhombic P2 2 2i space group and four molecules per cell) and B-histidine (monoclinic P2i space group and... 

The structure of the mineral brucite Mg(OH)2 (space group P2>m ) is formed by Mg(OH)g octahedra, which are connected by edges, forming layers parallel to the (001) plane (see Fig. 7). Hydroxyl groups OH lie on the 3-fold axes and each H-atom is equidistant from three oxygen atoms of the next layer, which is not a perfect position for forming hydrogen bonds between layers. 

Ni(2-0-C6H4-CH= =N CH3)2, space group P2 /c magnetic field along the crystallographic ... 

Cane sugar is generally available ia one of two forms crystalline solid or aqueous solution, and occasionally ia an amorphous or microcrystalline glassy form. Microcrystalline is here defined as crystals too small to show stmcture on x-ray diffraction. The melting poiat of sucrose (anhydrous) is usually stated as 186°C, although, because this property depends on the purity of the sucrose crystal, values up to 192°C have been reported. Sucrose crystallines as an anhydrous, monoclinic crystal, belonging to space group P2 (2). 

As a result of having two chiral centers, four stereoisomers of ascorbic acid are possible (Table 1) (Fig. 2). Besides L-ascorbic acid (Activity = 1), only D-araboascorbic acid (erythorbic acid (9)) shows vitamin C activity (Activity = 0.025-0.05). The L-ascorbic acid stmcture (1) in solution and the soHd state are almost identical. Ascorbic acid crystallizes in the space group P2 with four molecules in the unit cell. The crystal data are summarized in Table 2. 

In contrast to sulfurous acid, H2S03, which is not known as pure substance, the respective selenium compound can be obtained in crystalline form. H2Se03 crystallizes with the non-centrosymmetric space group P2 2,2] and contains pyramidal H2Se03 molecules.54 Within the molecules the bond lengths Se-O and SeOH differ by about 10 pm and the molecules are connected to puckered layers by strong hydrogen bonds. 

The molecular structure of 1,2,9,10-tetrastanna[2.2]paracyclophane 22 was determined by the X-ray diffraction method. The crystal belongs to the space group P2,/a, and the data collection was carried out at 13°C. The ORTEP drawing of 22 is shown in Fig. 8. 

A change in space group has also been observed for [Fe(3-OEt-salA-PA)2]C104-C6H5X (X=C1, Br) [128]. The space group for the chlorobenzene derivative is P2 /c at 296 K and converts to P2i/a at 158 K. A similar trans-... 

Figure 2.22 Models of packing of chains in form I of sPP according to space groups (a) Ibca59 and (b) P2 /a.146 Arrows indicate crystallographic twofold axes, present in (a) and lost in (b). In (b) chains are rotated by nearly 5° around chain axes, according to direction indicated by the arrows.

Figure 2.33 (a) Limit-ordered model (space group P2 /c) and (b) limit-disordered model (space... 

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