Hydrogen crystalline

The crystal structure of many compounds is dominated by the effect of H bonds, and numerous examples will emerge in ensuing chapters. Ice (p. 624) is perhaps the classic example, but the layer lattice structure of B(OH)3 (p. 203) and the striking difference between the a- and 6-forms of oxalic and other dicarboxylic acids is notable (Fig. 3.9). The more subtle distortions that lead to ferroelectric phenomena in KH2PO4 and other crystals have already been noted (p. 57). Hydrogen bonds between fluorine atoms result in the formation of infinite zigzag chains in crystalline hydrogen fluoride... 

It is found in this way that crystalline hydrogen at temperatures somewhat below the melting point is a nearly perfect solid solution of symmetric and antisymmetric molecules, the latter retaining the quantum weight 3 for the state with j = 1 as well as the spin quantum weight 3. This leads to the expression... 

In ordinary crystalline hydrogen there are three molecules with j = 1 for every one with j = 0. The eigenfunctions for these molecules approximate those for free molecules, namely... 

Crosslinking is not the only feature that may influence solubility. Such features as crystallinity, hydrogen bonding, or the absence of chain branching may all increase the resistance of a given specimen of polymer to dissolve. Some of these features are discussed later in the chapter. 

Kingery himself used XRD, but except in one case failed to positively identify crystalline hydrogen phosphates in any of the cements he examined. He found either the neutral orthophosphate or unidentified crystalline species and then the lines were weak. 

See entry crystalline hydrogen peroxidates See Sodium peroxoborate (next below)... 

See Other CRYSTALLINE HYDROGEN PEROXIDATES, GLASS INCIDENTS... 

A sample of the 1 1 complex exploded while being dried overnight in a desiccator. See Other CRYSTALLINE HYDROGEN PEROXIDATES... 

Murray, J. S., M. E. Grice, P. Politzer, and M. C. Etter. 1991a. A Computational Analysis of Some Diaryl Ureas in Relation to Their Observed Crystalline Hydrogen Bonding Patterns. Mol. Eng. 1, 95. 

A well-known consequence of the permutational symmetry of the nuclear Hamiltonian is the low-temperature entropy of crystalline hydrogen, which is associated with the spin statistics of ortho- and para-112 - See, e.g., N. Davidson, Statistical Mechanics (New York, McGraw-Hill, 1962), Chapter 9. 

See also crystalline hydrogen peroxidates See other N-o compounds, n-oxides... 

COMMERCIAL ORGANIC PEROXIDES, CRYSTALLINE HYDROGEN PEROXI-DATES... 

Crystalline hydrogen fluoride has been found38 to contain infinite zigzag chains with F—H -F distance 2.49 0.01 A and bond angle 120.1°. These values are more accurate than those for the gas phase. 

Treatment of the citrate monohydrate with a 20% excess of 70% hydrogen peroxide gave a crystalline product which, after vacuum drying at 50°C corresponded approximately to the tri(hydrogen peroxidate). It decomposed violently when disturbed with a porcelain spatula. See Other CRYSTALLINE HYDROGEN PEROXIDATES... 

Davies, A. G. et ai, J. Chem. Soc., Perkin Trans. 2, 1981, 1512 A sample of the 1 1 complex exploded while being dried overnight in a desiccator. See other CRYSTALLINE HYDROGEN PEROXIDATES... 

See CRYSTALLINE HYDROGEN PEROXIDATES See related REDOX COMPOUNDS... 

See also CRYSTALLINE HYDROGEN PEROXIDATES See other N—O COMPOUNDS, N-OXIDES... 

COMMERCIAL ORGANIC PEROXIDES CRYSTALLINE HYDROGEN PEROXIDATES CYCLIC PEROXIDES... 

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