Cations single-cation metals

To understand chemical exposure and bioavailability the biotic ligand model (BLM) was developed for single (cationic) metal species, assuming that the amount of a... 

Single-cation metals are those that form only a single ion. These are the main-group metals, and a few others. Sodium, Na, is a typical example. It forms only one cation, Na+, in chemical reactions. It never forms a cation with any other charge. 

Naming Compounds Involving Single-Cation Metals... 

On the other hand, when you read aluminum ion or aluminum in a name, you have to know that the charge on that aluminum ion is 3+ for calcium ion it s 2+ and so forth. A review of the charges of the single-cation metals is in order. Although zinc, cadmium, and silver are in the B-groups and not considered main-group elements, they are metals that form a single cation, and are included here also. 

The rules for naming binary ionic compounds with single-cation metals are as follows ... 

Numerous studies are reported on the electrokinetic removal of heavy metals from soils (Chapter 4). Many of these studies used ideal soils, often kaolinite, as a representative low-permeabiUty soil, which were spiked with a selected single cationic metal (such as lead and cadmium) in predetermined concentration. The spiked soil is loaded in a small-scale electrokinetic test setup and electric potential is applied. The transport and removal of the metal after specified test duration are determined. It is shown that cationic metals exist in soluble ionic form due to reduced pH near the anode regions and they are transported toward the cathode. However, when they reach near the cathode, they get sorbed or precipitated due to increased pH resulting from OH transport from the cathode. The actual removal from the soil is often negligible. 

It is apparent (Fig. 1.21) that at potentials removed from the equilibrium potential see equation 1.30) the rate of charge transfer of (a) silver cations from the metal to the solution (anodic reaction), (b) silver aquo cations from the solution to the metal (cathodic reaction) and (c) electrons through the metallic circuit from anode to cathode, are equal, so that any one may be used to evaluate the rates of the others. The rate is most conveniently determined from the rate of transfer of electrons in the metallic circuit (the current 1) by means of an ammeter, and if / is maintained constant it can eilso be used to eveduate the extent. A more precise method of determining the quantity of charge transferred is the coulometer, in which the extent of a single well-defined reaction is determined accurately, e.g. by the quantity of metal electrodeposited, by the volume of gas evolved, etc. The reaction Ag (aq.) -t- e = Ag is utilised in the silver coulometer, and provides one of the most accurate methods of determining the extent of charge transfer. 

S11CI2 Tin is not one of the metals that forms a single cation. With two -1 chloride ions, this compound is tin(II) chloride. 

MALDI is the method of choice for the analysis of synthetic polymers because it usually provides solely intact and singly charged [62] quasimolecular ions over an essentially unlimited mass range. [22,23] While polar polymers such as poly(methylmethacrylate) (PMMA), [83,120] polyethylene glycol (PEG), [120,121] and others [79,122,123] readily form [M+H] or [M+alkali] ions, nonpolar polymers like polystyrene (PS) [99,100,105,106] or non-functionalized polymers like polyethylene (PE) [102,103] can only be cationized by transition metal ions in their l-t oxidation state. [99,100] The formation of evenly spaced oligomer ion series can also be employed to establish an internal mass calibration of a spectrum. [122]... 

Another, and on the face of it, rather different example, is the coprecipitation of solid solution compounds, such as CulnSi and CulnSei—semiconductors of particular interest due mainly to their applicability for photovoltaic cells. It was shown, by X-ray diffraction, that the precipitate resulting from reaction between H2S and an aqueous solution containing both Cu" and In " ions was, at least in part (depending on the concentrations of the cations), single-phase CulnSi [3]. Two factors were found to be necessary for this compound formation (1) the presence of sulphide on the surface of the initially precipitated colloidal solid metal sulphide and (2) one of the cations being acidic and the other basic. The monovalent Cu cation is relatively basic, while the trivalent In cation is relatively acidic. It is not clear what the physical reason is for this latter requirement. A difference in practice between acidic and basic cations is that, in an aqueous solution of both cations, the acidic cation is more likely to be in the form of some hydroxy species (not to be confused with hydrated cations), while the basic cation is more likely to exist as the free cation. 

Coulomb correlation energy, I/44, and thereby showed how the cationic and anionic energy levels were both equally important. These workers calculated the gap arising in the charge excitation spectrum of a single transition-metal impurity hybridizing with a... 

Catalytic activity of metal ions coordinated to the framework of mesoporous molecular sieves atracted attention at first. Recently, catalytic activity of the metal ions incorporated into extraffamework positions of the MCM-41 in various reactions was also reported [3], But, the site geometry, coordination and distribution of the metal ions in the extraframework sites of the MCM-41 host matrix are not understood, and only a few papers have dealt with this problem. For dehydrated Mn-(A1)MCM-41, only one type of single cation was reported [4],... 

Oxidant Reduction test The Oxidant Reduction test evaluates the extent to which oxidative substances (e.g., chlorine, iodine, bromine) and some cationic metals (e.g., Cd, Cu, Ag, Hg) can be made less toxic or non-toxic by the addition of sodium thiosulfate. Sodium thiosulfate is typically added as a gradient of concentrations (based on its toxicity to the species of interest) to a single effluent concentration. 

Such examples have shown that the role of the cationic group 4 metal complexes in the coordination polymerisation of ethylene and oc-olefins with homogeneous single-site Ziegler-Natta catalysts must not be limited to those containing cyclopentadienyl-like ligands. 

In an interesting aside, many years after these synthetic capsules were first prepared, it was found that cells produce protein vaults that have similar encapsulating abilities but on a much larger scale. Whereas cryptands bind single alkali metal cations, vault proteins bind RNA composed of over 140 bases and other similarly sized guests. These biological crypts are discussed later. 

All crystals in this class are either insulators or semiconductors, and with a single exception (discussed in Sect. 3.3), they are ionic charge-transfer salts. The cations are generally either planar aromatics, such as TMPD+ and TTT+ (Sect. 3.2) or onium counter ions, such as Et4N+ and MePh3P+ (Sect. 3.3), although some cationic metal complexes are also known. For a majority of the systems, the anionic components are bis-1,2-dithiolene metal complexes, which have been studied and reviewed extensively81-84. ... 

The color of complex inorganic pigments results from the incorporation of cations of transition metals into the crystal of the host oxides. The host can be a single oxide such as Ti02 (rutile) or a mixed oxide such as TiZn204 (spinel) or MgAl204 (spinel). Most of the host oxides can be found as naturally occurring... 

The section above described how alkali metal species such as solvated M+ ions and M ions can be formed and isolated within the lattices ofcertainhquid solvents. It is also possible to obtain single alkah metal atoms (M) and clusters (usually cationic ones, (M) +) in various solid hosts such as zeolites and graphite. There is considerable interest in clustered species since they are especially relevant to the question of what has been called the "metal/nonmetal transition, that is, how many atoms need to be gathered together before metallic (rather than molecular, nonmetalhc) properties become apparent The few electron alkah elements lend themselves to state-of-the-art... 

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