Ice crystal structure

The ice crystal structure consists of water molecules hydrogen-bonded in a solid lattice. Since water molecules are similarly bonded in hydrates, both water molecules and hydrogen bonds are considered briefly in the following two sections. Many mechanical properties of ice are similar to hydrates, as detailed in Section 2.2. 

Figure 3-22. Left Ice crystal structure Right the iceane hydrocarbon molecule.

The effect of the Cl- ion on the ice structure is sufficiently different due to size effects, as the Cl- ion has a larger core than a Na+ ion. The rigid ice lattice is too dense for a Cl- ion, which in unconstrained ice forms a hydration shell of six nearest neighbours at a distance of 3.4 — 3.5A (Fig. 6b). The tendency to push out the nearest molecules causes more defects in the ice crystal structure essentially making it disordered on the scale of several lattice periods. 

In many food products, the desired crystalline structure provides a characteristic texture to the product. The crystals influence the texture by disrupting the continuous phase in which they are embedded. Ice cream or frozen desserts are good examples of this, where the ice crystal structure provides a certain characteristic smoothness and mouthfeel desired in the product. In these products, many small crystals of uniform shape and size are desired. If the crystals are too large, they can be detected in the mouth and the product is regarded as coarse. Crystal shape may also be important in some cases, although the effect of different shapes on product texture has not been studied in any quantified manner. 

ELIAS No, we have only one snowfall collected as it s coming down, but on the snowface you can easily identify the different events by the ice crystal structure. And we use this as a guideline for sampling. 

The tetrahedral symunetry of a water molecule defines the structural framework for the solid, ice. Crystal structures show that the water molecules in ice If, (the form that is stable at 0 °C at 1 atm pressure) have tetrahedral sy mmetry (see... 

In some cases, heat treatment, called annealing, is applied after the freezing step and before the two drying steps for homogenization of the ice crystal structure and, thus, for obtaining a more uniform and more permeable dry cake structure. It consists in... 

Caillet, A., Cogne, C., Andrieu, J., Laurent, P., Rivoire, A., 2003. Characterization of the structure of ice cream by optical microscopy Influence of freezing parameter on ice crystal structure. Lebensm. -Wiss. u. -Technol. 36 743-749. 

Ogawa, K. and Majumdar, A. (1999) Molecular-level imaging of ice crystal structure and dynamics by atomic force microscopy. Microscale Thermophys. 

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