Electron-Density Distributions in Inorganic

Electron density distributions in inorganic compounds. K. Toriumi and Y. Saito, Adv. Inorg. Chem. Radiochem., 1983, 27,27-81 (94). 

Crystallographic studies of transition metal hydride complexes Stereochemistry of six-coordination Five-coordinate structures Stereochemistry of five-coordinate Co complexes Absolute stereochemistry of chelate complexes Stereochemistry of optically-active transition metal complexes Electron density distributions in inorganic compounds... 

VI. Electron-Density Distributions in Some Inorganic Crystals. 76... 

We shall also outline how bond distances and information pertaining to the distribution of electron density may, in principle, be extracted from measurements carried out using electron microscopy. Finally we touch upon future possible lines of development likely to be of value to the inorganic, surface and analytical chemist. 

Owing to the relatively good crystallinity and the large number of OOZ reflections observed for the hydro calumite derivative, the electron density distribution along the c axis can be estimated using a series of OOZ reflections, in accordance with previous literature [82,83]. One-dimensional electron density calculations based on X-ray diffraction are often carried out to probe the structure of the intercalated species in two-dimensional inorganic hosts [33,84-86]. This yields specific information about the orientation and structure of the intercalated species or at least ehminates certain conformational possibihties, which are incompatible with the diffraction data. In LDH systems, however, such calciflations are usually impossible because the X-ray diffraction patterns of hybrid materials are often very ill defined [87,88]. 

Bonds to Hydrogen.—From a consideration of recent 2f-ray diffraction studies on inorganic complexes it has been concluded that, in general, hydrogen atoms fixed in calculated positions with N—H = 0.87 A provides the best description of the electron density distribution. 

It is also possible to prepare crystalline electrides in which a trapped electron acts in effect as the anion. The bnUc of the excess electron density in electrides resides in the X-ray empty cavities and in the intercoimecting chaimels. Stmctures of electri-dides [Li(2,l,l-crypt)]+ e [K(2,2,2-crypt)]+ e , [Rb(2,2,2-crypt)]+ e, [Cs(18-crown-6)2]+ e, [Cs(15-crown-5)2]" e and mixed-sandwich electride [Cs(18-crown-6)(15-crown-5)+e ]6 18-crown-6 are known. Silica-zeolites with pore diameters of vA have been used to prepare silica-based electrides. The potassium species contains weakly bound electron pairs which appear to be delocalized, whereas the cesium species have optical and magnetic properties indicative of electron locahzation in cavities with little interaction between the electrons or between them and the cation. The structural model of the stable cesium electride synthesized by intercalating cesium in zeohte ITQ-4 has been coirfirmed by the atomic pair distribution function (PDF) analysis. The synthetic methods, structures, spectroscopic properties, and magnetic behavior of some electrides have been reviewed. Theoretical study on structural and electronic properties of inorganic electrides has also been addressed recently. ... 

Resonance structures are diagrammatic tools used predominately in organic chemistry to symbolize resonant bonds between atoms in molecules. The electron density of these bonds is spread over the molecule, also known as the delocalization of electrons. Resonance contributors for the same molecule all have the same chemical formula and same sigma framework, but the pi electrons will be distributed differently among the atoms. Because Lewis dot diagrams often cannot represent the tme electronic stmcture of a molecule, resonance stmctures are often employed to approximate the tme electronic stmcture. Resonance stmctures of the same molecule are connected with a double-headed arrow. While organic chemists use resonance stmctures frequently, they are used in inorganic stmctures, with nitrate as an example. 

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