Internal salt structure

Fig. 9. Pictorial representation of the internal salt structures formed when two oppositely charged monomers are copolymerized...

PhosphorylctK ine (PC) group takes internal salt structure stably with 6-alo>ms ring structure. 

The physical origin of this structural flexibility of the FeO overlayer is still unclear, the more so since no clear trend is observable in the sequence of lattice parameters of the coincidence structures. The FeO(l 11) phase forming up to coverages of 2-3 ML is clearly stabilized by the interactions with the Pt substrate since FeO is thermodynamically metastable with respect to the higher iron oxides [106,114], FeO has the rock salt structure and the (111) plane yields a polar surface with a high surface energy [115], which requires stabilization by internal reconstruction or external compensation. The structural relaxation observed in the form of the reduced Fe—O... 

These and related compounds are represented as having associated structures since the more familiar (e.g., Refs. 2,3,91) internal salt or anhydrohydroxomercuriocarboxylate structure, e.g.,... 

The discovery of high Tq superconductivity in La2-xMxCu04 (M = Ba, Sr) (Bednorz and Muller 1987) based on perovskite and rock-salt structures has led to an international effort in superconductivity research over the last decade. The principles that govern superconducting copper-oxide-based materials have enormous significance in the application of these oxides as potential catalysts... 

On the basis of the interaction of metal ions and AV-pH and AV-log C plots (41, 43), we propose ionic structures for dioleoyl, egg, and di-palmitoyl lecithin monolayers represented in Figure 1. Schematically shown in Figure 1A is the internal salt linkage between the phosphate and trimethylammonium groups in dioleoyl lecithin, preventing the inter-... 

Pyrazolo[4,3-c]pyridines gave 5-methiodides in excellent yield.144 154 A methiodide of pyrazolo[l,5-a]pyridine 199b (R1 = H) was also prepared but its structure was not assigned161 the parent compound 5 quaternized in the 1-position.209 The saturated amide, however, formed a 7a-quaternary salt (263) with benzyl chloride, which was converted to the 1-benzyl derivative via the internal salt 264.209... 

Mesoionic structures and other internal salts may display a molecular ion of an ambiguous structure which is isobaric with the original molecule. Since the fragmentation patterns of... 

The effects listed above are most evident at low salt concentrations, so cation exchange is best studied at moderate salt concentrations when thermodynamic data is to be measured. However salt concentrations must be kept below the conditions at which neutral salt imbibition (ingress of salt molecules into the internal zeolite structure via a Donnan mechanism) can occur. This has been suggested [33] to be below 1M. 

Structural formula (A) contains both an amino group (a base) and a carboxyl group (an acid). Proton transfer from the stronger acid (— COOH) to the stronger base (— NH2) gives an internal salt therefore, (B) is the better representation for alanine. Within the field of amino acid chemistry, the internal salt represented by (B) is called a zwitterion (Chapter 18). 

In Chapter 18, we discuss a class of compounds called amino acids, so named because they contain both an amino group and a carboxyl group. Following is a structural formula for the amino acid alanine in the form of an internal salt ... 

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