Ordered and disordered networks

Let us return finally then to consider the crucial question which can often arise in diffraction studies of proton conducting systems in an otherwise close to centrosymmetric non-hydrogen-atom network, how do we ascertain unequivocally whether a given hydrogen bond is genuinely disordered, and hence a potential structural source of proton mobility The 

How can the earlier inconsistencies be reconciled with this result What was going wrong Clearly, the structure is truly non-centrosymmetric, but the hydrogens are the only atoms which diverge significantly from 

In view of the severity of the complications which can be experienced in assessing, by diffraction methods, the degree of order in a short hydrogen bond, it is important to state that vibrational spectroscopy (Raman, IR and neutron inelastic scattering) can provide definitive evidence as to the local effective symmetry of the bond see, for example. Chapters 21, 23 and 24. Indeed, in situations of this type, an ideal requirement would be that a mutually consistent structural and vibrational description be achieved before our diffraction-obtained structural picture can be accepted unequivocally. 

Thomas, R. Tellgren and I. Olovsson, Acta Cryst. B30 (1974a) 1155-66. 

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The hydrogen bond and protonic species 5.5 Ordered and disordered networks... 

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