Ionic volumes

Figure 6. Graph of Retention Volume of a Series of Ions against Their Ionic Volume...

Mg2+ has properties that make it quite unique among biological cations. Inspection of Table 10.1 reveals that of the four common biological cations, the ionic radius of Mg2+ is much smaller than the others, whereas its hydrated radius is the largest of all four. This means that the volume of the hydrated Mg2+ cation is 400 times larger than its ionic volume (since the radius enters into the equation to the power three), compared to values around 25 times for Na+ and Ca2+, and a mere 5 times for K+. [Pg.165]

Cation Ionic radius (A) Hydrated radius (A) Ionic volume (A3) Hydrated volume (A3) Exchange rate (s ) Transport number... [Pg.166]

Metal ions, because they are positively charged, act as electrophiles that is, they seek the possibility of sharing electron pairs so that a bond or a charge-charge interaction can be formed and electrical neutrality can thereby be attained. In these types of interactions, metal ions act like hydrogen ions (i.e., protons), except that they have a greater ionic volume... [Pg.2]

Weber A., Sauer B., Muller A.C., Herbstritt D., Ivers-Tififee E., 2002. Oxidation of H2, CO and methane in SOFCs withNi/YSZ-cermet anodes. Solid State Ionics Volumes 152-153, pp. 543-550. [Pg.90]

Plots of ionic polarizability against ionic volume are approximately linear with the slope oc/Vm increasing with cation charge. [Pg.59]

While the study of solvatochromic dyes is well established as a means of probing solvent polarity, these are not the only solutes that can be used in this fashion. A more exotic solvatochromic probe is an excess electron in solution. Optical absorption studies of the thermalized (solvated) electron generated in the pulse radiolysis of a series of ILs show a strong dependence on cation character, with a relatively low frequency for tetraalkylammonium systems and a higher frequency for cyclic (pyrrolidinium-based) cations [48, 207]. The solvated electron spectrum is often interpreted in a particle-in-a-box framework, which would imply that the cyclic cations (which possess smaller ionic volumes) simply coordinate more closely with the electron and so create a smaller domain in which the electron must localize. The breadth of the absorptions and their maximum fall within the range of values expected for moderately polar organic solvents. [Pg.111]

The ionic radius of aluminum (0.50 A) is 2.5 times that of boron (0.20 A), and the ionic volumes are in a ratio of about sixteen to one these ratios make it easy to understand why boron in its oxidized form exhibits behavior so much more acidic than that of trivalent aluminum and thus why boron is regarded as a typical metalloid although its congeners are metals. [Pg.126]

Concentrative refractivity — This is the first derivative of the refractive index of a solution over the concentration of a given species (dn/dC). The variations of the refractive index due to the inhomogeneous spatial concentration of chemical species can be decoupled as (dn/dC) = (dn/dp)c(dp/dC) + (dn/dC)p where the first term is related to the molecular (or ionic) volume of solvated species and the second one is associated to the electronic structure of such species [i]. The value of (dn/dCj) can be considered a constant for rather diluted aqueous solutions and therefore, it is characteristic for each solvated species [ii]. [Pg.108]

Conway, B.E., Novak, D.M. and Laliberte, L. Salting-out and ionic volume behavior of some tetraalkylammonium salts. J. Solution Chem. 1974, 3, 683-711. [Pg.23]

How Does One Obtain Individual Ionic Volume from the Partial Molar Volume of Electrolytes ... [Pg.56]

The status of research and early work on the chloride requirement in the PS II/OEC has been reviewed recently [15,19]. Cl", like Ca , exerts its function in the electron transfer reactions which lead to O2 evolution and is not apparently required for PS II primary photochemistry. Ionic volume appears to be the key in... [Pg.138]

Alkali-Graphite Compounds with Atomic and Ionic Volumes... [Pg.246]

Compound Increment of alkali metal in the graphite compourds Atomic volume Me in metals Ionic volume Me+ in salts... [Pg.246]

J. O. M. Bockris and A. K. N. Reddy, Modern Electrochemistry Ionics, volume 1, 2nd edition (New York Plenum Press, 1998). [Pg.501]

The perchlorate anion is a tetrahedron with four oxygen molecules at the comers and a chlorine molecule at the center. Perchlorate, with a partial molal ionic volume of 44.5, has a similar ionic size as iodide with a partial molal ionic volume of 36.7 at 25°C. Because of its chemical properties, perchlorate is a competitive inhibitor of the process by which iodide circulating in the blood is actively transported into thyroid follicular cells. The site of this inhibition is... [Pg.105]

Cation Ionic Radius (A) Hydrated Radius (A) Ionic Volume (A ) Hydrated Volume (A ) Exchange Rate (s ) Transport Number... [Pg.197]

Clinical studies show the following ions competitively inhibit the mammalian thyroid I- transport CIO4 (perchlorate) > ReOJ (perrhenate) > BF4 (fluoroborate) > SeCN- (selenocyanate) > SO3F- (fluorosulfite) > SCN- (thiocyanate) > I > NO (nitrate) > OCN (cyanate) > Br (bromide)2. They are all monovalent anions with a partial molal ionic volume of 25-50 ml/mole. Most of them are spherical or... [Pg.402]

Big Chemical Encyclopedia

Chemical substances, components, reactions, process design ...