Tables crystallographic information

The data analysis in Table 9.3 summarizes the crystallographic information of the Co-Mo-S phase active for hydrodesulfurization. The Co-S distance in Co-Mo-S is 0.22 nm, with a high sulfur coordination of 6.2 1.3. Each cobalt has on average 1.7 0.35 molybdenum neighbors at a distance of 0.28 nm. Based on these distances and coordination numbers one can test structure models for the CoMoS phase. The data are in full agreement with a structure in which cobalt is on the edge of a MoS2 particle, in the same plane as molybdenum. 

International Tables for X-Ray Crystallography, Vol. 1, Symmetry Groups, N.F.M. Henry and K. Lonsdale, Eds, International Union of Crystallography, Kynoch Press, Birmingham, 1952. The complete source for space groups and crystallographic information. 

The data analysis in Table 9.3 summarizes the crystallographic information of the Co-Mo-S phase active for HDS. The Co-S distance in Co-Mo-S is 0.22 nm, with a high sulfur coordination of 6.2 + 1.3. Each cobalt has on aver-... 

Computerizing the information on zeolite catalysts have been attempted successfully and different databases concentrate on specific properties[25-28]. The information in several databases are shown in Table 3. Our approach[29] involves retrieval of information from the database and additionally an expert system approach is followed to derive a set of conditions to achieve one s goal in the synthesis of zeolites. The structure of the system is designed to perform three salient fiinctions as shown in Fig. 7. The first function is to provide access to a large database of physico-chemical properties and crystallographic information of all reported zeolite[30]. The second function provides for the synthesis of zeolites - the most logical route for the synthesis of a desired zeolite structure is provided. The third function is a graphic tool application to simulate X-ray powder diffraction patterns for zeolite phases with different amount and nature of purity. 

A thermodynamic optimization of the system was performed by Domer (1982) [167]. This dataset was later refined by Lim and Lukas (1996) [36]. Due to additional crystallographic information concerning the extended homogeneity range of the boron carbide phase [152, 168] a further assessment was necessary [33, 34,169]. Data for the calculated invariant reactions are given in Table 13. Boron carbide of composition 16.4 at.% C melts congruently at 2731 K. 

Since the initial report of (5), similar bis(//-oxo)dicopper(III) complexes with a variety of ligands have been reported,some of which [(d28-i-Pr4DTNE)Cu 2(M 0)2f (6) [(Lme)2Cu 2(m-0)2]"+ (7), " [(Me2TPA)2Cu""2(M-0)2]"+ (8), and [(t-Bu2P(NSiMe3)2-)2Cu 2 (/2-0)2p+ (9), " also have been characterized by X-ray crystallographic analysis (Table 2). In the absence of X-ray crystallographic information, the presence of the bis(/u-oxo)dicopper(III) core has also been deduced by X-ray absorption fine structure (EXAFS) spectroscopy. 

Two solid solutions, a (bcc (A2) and y (fee (Al), and four intermediate binary phases a, p (FeyMog), (Laves phase, Fe2Mo) and the high temperature R phase, all with signifieant solubility of the third element, exist in this system. One ternary phase, Ti, was found. Miseibility gaps are found in the a phase in both the Cr-Fe and Cr-Mo systems. The crystallographic information available is shown in Table 2. 

Crystallographic information on the ternary compounds is summarized in table 14 (overleaf). 

Most of the sections contain stractural data. The stmctural details are supported by a rrum-ber of tables summarizing important crystallographic information. Only those data that have been obtained reliably, usually by X-ray single crystal diffraction or high qrrahty X-ray powder diffraction, are considered. For some compotmds the stmcture determinations has been carried out several times. In these cases the tables will contain all data for comparisoa... 

In some specific cases one would like to convert the chemisorption data into an averaged particle size. In that case, the number of surface atoms per unit surface area (density of surface atoms) is an essential parameter. Since this number depends on the type of the crystallographic plane, (see Table 3.7), one also needs information on the types of crystallographic planes exposed to the gas phase. This is also important for another reason the adsorption stoichiometry may depend on the crystallographic plane. 

Crystallographic papers do not show most of the data for the experiments. This is found in the raw structure factor files that are often deposited along with the coordinates for the model (O Section 4.3). The papers report numbers designed to inform the reader as to the accuracy of the data and the validity of the model. This is usually contained in one or two tables (O Figure 22-5). 

The crystallographic data contain all the information about the data that were used for determining the model. The most important information is the resolution. This refers to the minimum d spacing (O Eq. 22.1) and indicates the smallest distance between two atoms that can be resolved, i.e., completely separated based on electron density. The table also contains space group (P2i2i2i) and unit-cell information along with the statistical measurements for the reflection data. 

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