Single crystals preparation

On the other hand, in the single crystals prepared from equivalent amounts of heterochiral 1 1 complexes, a pair of two heterochiral 1 1 complexes are incorporated in a unit cell to form a layered structure with alternate layer distances of 7.33 and 7.6 A. Two perchlorate ions stay in the narrower gap, and two additional acetone molecules as crystallization solvent occupy the wider gap. The perchlorate ions interact with two axial water ligands by hydrogen bonds (3.71 and 3.77 A) to construct a layered structure. The adjacent two molecules of heterochiral 1 1 com-... 

In terms of photoelectrode material quality, single crystals comprise a rational choice since their bulk properties can be controlled better and their influence on cell performance may be evaluated in a rather accurate manner, as being microstruc-turally well-defined solids. However, the cost and convenience of single-crystal preparation are not suited to the practical requirement of cheap device components. Polycrystalline photoelectrodes are advantageous in terms of fabrication cost, ability to prepare large areas in one operation, and material economy. 

The transition-state model of this reaction has been proposed as (1), based on X-ray analyses of single crystals prepared from Ti(OPr )4, (R,R)-diethyl tartrate (DET), and PhCON(OH)Ph and from Ti(OPr )4, and (R,R) N,/V -dibenzyltartramide.30-32 The Z-substituent (R2), located close to the metal center, destabilizes the desired transition state and decreases enantioselectivity (vide supra). When the Z-substituent is chiral, face selection induced by the substituent strongly affects the stereochemistry of the epoxidation, and sometimes reversed face selectivity is observed.4 In contrast, the. E-substituent (R1) protrudes into an open space and E -allylic alcohols are generally good substrates for the epoxidation. 

JCPDS card 25-0297 Single crystal prepared from the elements... 

Since polymer single crystals prepared these days are too small for x-ray diffraction experiments, the Crystal Structure of a polymer is generally determined from x-ray patterns of a fibre drawn from the polymer. Due to the alignment of the crystalline regions with the long axes of the molecules parallel to the fibre axis, the pattern is essentially identical to a rotation pattern from... 

Single-crystal preparation by means of chemical transport reactions. (Ni-Sn-S compounds as an example)... 

Fig. 5. UO2 single crystals prepared by chemical vapour transport with TeCl4...

Recently, single crystal preparations from natural (1 3) and synthetic (A,5) polymers have become a well established art. 

Water adsorption on MgO(lOO) is the best studied system so far [64, 75-77]. The groups of Heidberg [75], Weiss and Toennies [76] have studied it with IR, FEED and HAS. While these groups have used surfaces prepared through in situ cleavage, Stimimanet al. [78] have employed bulk single crystals prepared via... 

Figure 4.29 Scanning electron micrographs of MOR single crystals prepared using two silica sources. Reproduced with permission from [92]. Copyright (1998) Elsevier...

FIGURE 1.10 Current intensity versus electrode potential voltammetric profile for platinum single crystals, Pt(100) (cooled in air) with blue lines, Pt(110) with black lines and Pt(lll) in red lines, in 0.5 M sulfuric acid solution run at 0.05 V s 1 at room temperature. A difference with respect to the early single crystal preparation method by Will [18] is that the ones reported here are those obtained by Clavilier early in 1980. After 50 years of the first paper by Will on the use of single crystals for the oxygen electroreduction reaction and his finding of the given preferred activities on (111) and (100) planes, the industry still uses polycrystalline surfaces. 

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