Sphere formation

Unfortunately, for ligands of strong acids, this equation may underestimate the stability constant as it calculates values for inner sphere formation only. Eigen (22) has proposed that the formation of complexes proceeds sequentially as follows ... 

In the body of a liquid, intermolecular forces pull the molecules in all directions. At the surface of the liquid, the molecules pull down into the body of the liquid and from the sides. There are no molecules above the surface to pull in that direction. The effect of this unequal attraction is that the liquid tries to minimize its surface area. The minimum surface area for a given quantity of matter is a sphere. In a large pool of liquid, where sphere formation is not possible, the surface behaves as if it had a thin stretched elastic membrane or skin over it. The surface tension is the resistance of a liquid to an increase in its surface area. It requires force to break the attractive forces at the surface. The greater the intermolecular force, the greater the surface tension. Polar liquids, especially those that utilize hydrogen bonding, have a much higher surface tension than nonpolar liquids. 

I promised Dr. Swaddle that we would look at nickel and ammonia. We have made such a study in 15-molar aqueous ammonia which is a mixed solvent system. It is really only necessary to obtain solvent interchange between the inner-sphere and the outer-sphere in a case like this because outer-sphere formation is diffusion controlled. In this system we obtain a positive... 

The separation of the two stages is easier to discern when the rates of the two processes are so different, but it can also be seen in the ultrasonic spectra of metal-sulfate systems (Sec. 3.4.4). Ultrasonic absorption peaks can be attributed to formation of outer-sphere complexes (at higher frequency, shorter t) and collapse of outer-sphere to inner-sphere complexes (at lower frequency). In addition to uv spectral and ultrasonic detection, polarimetry and nmr methods have also been used to monitor and measure the strength of the interaction. There are difficulties in assessing the value of ATq, the outer-sphere formation constant. The assemblage that registers as an ion pair by conductivity measurements may show a blank spectroscopically. The value of Aq at T" K may be estimated using theoretically deduced expres-... 

Agglomeration in liquid media Fine coal preparation Sphere formation... 

Cenospheres and oil coke are formed as a result of liquid phase cracking reactions, and, with the exception of ash, account for the major portion of the weight of particulate matter emitted when burning heavy fuel oils. Fuel composition and atomization quality appear to be the dominant parameters controlling ceno-sphere formation. 

As shown by the values of the formation constants found by solvent extraction (overall formation constants] and by spectrophotometry (inner sphere formation constants], it is safe to assume that azide complexes are mostly inner sphere. This is also supported by the values of the formation constant of Eu (III] calculated using the charge transfer band whose appearance must be attributed to close contact between azide and metal ion. 

The amine-based Henry reaction catalyst was encapsulated via the interfacial polymerization of oil-in-oil emulsions. PEI was encapsulated by dispersing a methanolic PEI solution into a continuous cyclohexane phase. Upon emulsification, 2,4-tolylene diisocyanate (TDI) was added to initiate crosslinking at the emulsion interface, forming polyurea shells that contain free chains of PEI. The microcapsules crenate when dry and swell when placed in solvents such as methanol and dimethylformamide, suggesting a hollow capsule rather than a solid sphere formation. The catalyst loading was determined to be 1.6 mmol g . ... 

Fuoss (15) proposed an equation which has been used frequently to calculate outer sphere formation constants. The equation has the form ... 

Analysis of the entropy changes, indicates essentially 100% inner sphere formation for the Ac, 3 ClPr and ClAc complexes, 50% inner sphere for the CI2AC complexes. However, a study of 139La nmr shifts (18) was interpreted to show only 50% inner sphere character for LaClAc+2 and 20-25% for LaCl2Ac+. In light of this lack of agreement, we have analysed the complexation by another approach which would seem to be more justified than the entropy based estimations. 

J/m/K. The agreement between the nmr estimates and those from equation (1) add weight to the estimates in Table III. In Figure 2 the variation of log i and log 0 as functions of pKa reflect the vital role of ligand basicity in the inner-outer sphere competition. These curves indicate that the cross-over from predominantly outer sphere to predominantly inner sphere occurs near pKa values of 2. However, since the enthalpy and entropy changes for inner sphere complexation are larger than for outer sphere formation, both AH and AS would still be endothermic (characteristic of inner sphere reaction). 

AZO POLYMER COLLOIDAL SPHERES FORMATION, TWO-DIMENSIONAL ARRAY, AND PHOTORESPONSIVE PROPERTIES... 

Figure 5.7. Schematic representation of the sphere formation process and some TEM images of the samples obtained from the suspensions with different water contents. Water content (vol%) (a) 20%, (b) 30%, (c) 40%, and (d) 50%. The scale bars in the figures are 100nm. Source From Li et al., 2006a.

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