Ctystallization

Wood While fairly inert chemically, wood is readily dehydrated by concentrated solutions and hence shrinks badly when subjected to the action of such solutions. It is also slowly hydrolvzed by acids and alkalies, especially when hot. In tank construction, if sufficient shrinkage once takes place to allow ctystals to form between the staves, it becomes very difficult to make the tank tight again. 

Here ao is the lattice parameter of die ctystal. An approximate value for the bond energy, , for this structure where the co-ordination number, Z, equals twelve is given by... 

Another important ctystal structure incorporating two ionic species is spinel, which has tire composition AB2O4, or AO B2O3. In this phase one-third of the cations occupy teU alredrally oxygen co-ordinated sites, and two-tlrirds occupy octahedrally co-ordinated sites. 

Note These data have been obtained from die complete tirermodynamic data tabulated in Kubaschewski et al. (loc. cit.), with the approximation of tire simple two-term equation. This should serve for calculations not requiring an accuracy of better than 2kJmoG 02, which is normally the case for industrial applications. Solid state ctystal transformations which usually only have relatively small heats of transformation, have been ignored. 

Figure 6. l pical size distributions by volume for the fines flow and the product flow obtained from a 970-L pilot plant ctystallizer operated with fines removal. The ordinate value is defined by volume percentage divided by interval width. 

Figure 4. Correlation between ctystal growth rate and initial supercooling.

In fact, the phenomenon and conditions described here can be applied not only to a beam of electrons, but also to a beam of X-rays.12 What is the difference in the diffraction pattern when these different sources of radiation are applied to an ordered array of atoms X-rays penetrate deeply into the ctystal, and information between spacing of planes inside the crystal is obtained from the diffraction pattern. In contrast, the use of low-energy electrons as a source of incident radiation with energies in the range of 10 to 500 eV ensures that only atoms close to the surface (one or two planes) produce the diffraction pattern. Since this is the region in contact with a solution, the region where electrochemical processes occur, LEED is the technique used in electro-... 

The term "cutionic water" may be used to describe the situation in which water appears in coordination compounds apparently joined to cations by covalent bonds. However, the fact that a number of such compounds exhibit "hydrate isomerism" is evidence for cationic bonding, as well as it is lor the existence of other harms of these compounds in which Ihe presence of Water is due to electrostatic attractions or ctystal stability requirements. 

TAMM LEVELS. Surface states the extra electron energy levels found at ctystal surfaces,... 

The electrostatic modd for the hydrated vanadyl ion consists of V,+ situated in a tetragonal dectric fidd caused by the oxide ion and five water dipoles. The ctystal fidd energy levd diagram for such a situation is given in Fig. 1. 

In, Co etc (Ref 3). Alums are prepd by mixing aq solns of the corresponding salts and ctystallizing out the aium. Alums are all soluble in water and ctystallize with 24 moles... 

Aubertein and Emeury [29] made a detailed examination of the causes of foaming. Oxidation of non-sulphonated resorcinol is the original cause of gas evolution during nitration. When the product is in the form of very fine crystals the gas bubbles attach themselves to the crystals and raise the product to die surface in the form of a foam. This does not occur when the crystals of die product are large. Therefore, die method of nitration should be such as to favour formation of large ctystals of styphnic acid. To achieve this, Aubertein and Emeuty advise ... 

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