Morphology and Habit

Strictly speaking, morphology and habit axe 2) An open form is one which does not enclose... 

The morphology and habit exhibited by a crystal are controlled by a combination of the internal crystal structure of the unit cell and the external growth parameters. The morphology that is observed is in general a consequence of... 

Scanning electron microscopy can provide very detailed images with a great deal of magnification to demonstrate the morphology and habit of crystalline material. This technique can provide a great deal of information about the surfaces of the crystals, as well as their overall shape. When combined with energy... 

The effects of surfactants on the crystallization patterns of other food components were also studied. Surfactants affect the crystallization of sugars (sucrose, sorbitol, glucose, fructose, etc) from aqueous solutions. Surfactants affect yields of crystallization, rates of precipitation and crystallization, mode of crystallization, crystal stmctures, and crystal morphologies and habits. Surfactants also affect crystal size and amounts of impurities that cocrystallize. The effects are tremendous, and an almost endless number of effects have been described. In many cases, the studies are descriptive and the mechanisms involved in these effects are stiU obscure. 

Products. In all of the instances in which crystallization is used to carry out a specific function, product requirements are a central component in determining the ultimate success of the process. These requirements grow out of how the product is to be used and the processing steps between crystallization and recovery of the final product. Key determinants of product quaHty are the size distribution (including mean and spread), the morphology (including habit or shape and form), and purity. Of these, only the last is important with other separation processes. 

I 4 Crystal morphology and size Tab. 4.2 Habits of iron oxides... 

Sturm, E.A. and Horn, M.H., Food habits, gut morphology and pH, and assimilation efficiency of the zebraperch Hermosilla azurea, an herbivorous kyphosid fish of temperate marine waters, Mar. Biol., 132, 515, 1998. 

The crystal size distribution, crystal habit (shape or morphology), and bulk density. 

Of critical importance in the development of DPI products is the evaluation, optimization, and control of flow and dispersion (deaggregation) characteristics of the formulation. These typically consist of drug blended with a carrier (e.g., lactose). The properties of these blends are a function of the principal adhesive forces that exist between particles, including van der Waals forces, electrostatic forces, and the surface tension of adsorbed liquid layers [7], These forces are influenced by several fundamental physicochemical properties, including particle density and size distribution, particle morphology (shape, habit, surface texture), and surface composition (including adsorbed moisture) [8]. In addition,... 

Once crystals are obtained, they must be placed in the x-ray beam in order to record the diffraction pattern. The experimenter should use care in choosing the crystal. First, it should have the same morphology or habit as the majority of crystals in the drop because crystals having similar habits should, in most cases, have the same unit cell and crystal symmetry. It also makes it easier to find isomorphous crystals for heavy... 

Ohba N. External morphology and feeding habits of the New Zealand glowworm Arachnocampa luminosa (Diptera Mycetophilidae). Sci Rept Yokosuka City Mus 2002 49 13-22. 

Crystal morphology or habit is important, since it can influence many properties of the compound. For example, powder flow properties, compaction and stability have all been found to be dependent on crystal morphology. It has been shown that tolbutamide B (platelike)... 

Crystallization also is employed as an intermediate purification step in many processes because of good separation factors per stage and its effectiveness at low temperatures for thermally labile compounds. Particle size and habit are important in these steps as well because of their effect on filtration or centrifugation rates. The influence of crystallization conditions on morphology and PSD, and, therefore, on the de-liquoring characteristics is often overlooked when laboratory work is conducted. However, this becomes much more important in pilot- or full-scale manufacturing where slow de-liquoring can result in low productivity and reduced stability. 

Crystallinity The degree of crystallinity must be known. Amorphous materials are thermodynamically not stable, and stabilization is likely to take place under a broad range of conditions and half-life times. The morphology and crystal habit is of interest for mechanical processing procedures such as milling, mixing, powder flow and compression. 

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