Conductivity alkali metal

Ionic Cations and anions Electrostatic, non-directional Hard, brittle, crystals of high m.t. moderate insulators melts are conducting Alkali metal halides... 

A possible explanation for the sharp increase in conductivity of the ceria electrolytes that occurs in contact with the proton-conducting alkali-metal carbonates or with nonconducting oxides was offered in a paper by Zhu et al. (2003). Adsorption of an excess number of oxygen ions (0 ) is possible at the contact surface areas between the nanoparticles of the two phases. In this way a new, additional interfacial conduction pathway is opened up for the ionic current. 

The development of these solid state batteries hinged on the discovery of the fast ion conductions or solid electrolytes, e.g. alumina and lithium nitride (Li3N) which are capable of conducting alkali metals. 

Modem solid state batteries nse polymeric electrolytes. Heteroatom containing high molecular weight polymers can conduct alkali metals. 

Sodium [7440-23-5] Na, an alkali metal, is the second element of Group 1 (lA) of the Periodic Table, atomic wt 22.9898. The chemical symbol is derived from the Latin natrium. Commercial iaterest ia the metal derives from its high chemical reactivity, low melting poiat, high boiling poiat, good thermal and electrical conductivity, and high value ia use. 

The doping of Ceo with alkali metals creates carriers at the Fermi level in the tiu-derived band and decreases the electrical resistivity p of pristine solid Ceo by several orders of magnitude. As x in Ma C6o increases, the resistivity p(.-r) approaches a minimum at x = 3.0 0.05 [9, 112], corresponding to a half-filled flu-derived conduction band. Then, upon further increase in x from 3 to 6, p x) again increases, as is shown in Fig. 11 for various alkali metal dopants... 

As future outlook, it would be of great relevance to be able to eventually enhanee the intrinsic conductivity of CNTs. In this respect, the latest development in alkali metal intercalated CNTs looks rather promising. In faet, Chauvet et al. recently sueeeeded to dope aligned CNT by potassium and found that the Pauli susceptibility increases a factor of 3 upon doping, indicating that K-doped tubes are still good eonductors [23]. 

These data, and the other properties of C M, suggest that bonding occurs by transfer of electrons from the alkali metal atoms to the conduction band of the host graphite. Consistent with... 

Some of the alkali metal-group 15 element systems give compounds of stoichiometry ME. Of these, LiBi and NaBi have typical alloy stmc-tures and are superconductors below 2.47 K and 2.22 K respectively. Others, like LiAs, NaSb and KSb, have parallel infinite spirals of As or Sb atoms, and it is tempting to formulate them as M+ (E )" in which the (E )" spirals are iso-electronic with those of covalently catenated Se and Te (p. 752) however, their metallic lustre and electrical conductivity indicate at least some metallic bonding. Within the spiral chains As-As is 246 pm (cf. 252 pm in the element) and Sb-Sb is 285 pm (cf. 291 pm in the element). 

Many of the ionic fiuorides of M, M and M dissolve to give highly conducting solutions due to ready dissociation. Some typical values of the solubility of fiuorides in HF are in Table 17.11 the data show the expected trend towards greater solubility with increase in ionic radius within the alkali metals and alkaline earth metals, and the expected decrease in solubility with increase in ionic charge so that MF > MF2 > MF3. This is dramatically illustrated by AgF which is 155 times more soluble than AgF2 and TIF which is over 7000 times more soluble than TIF3. 

The compounds can therefore be used as nonaqueous ionizing solvent systems (p. 424). For example the conductivity of ICl is greatly enhanced by addition of alkali metal halides or aluminium halides which may be considered as halide-ion donors and acceptors respectively ... 

Hexamethylphosphoric triamide (HMPT) is a high-boiling solvent particularly satisfactory for dissolving metals or organometallic compounds. It has been found to be an ideal solvent in which to conduct the reduction of a,jS-unsaturated ketones by alkali metals. 

Ionic bond, 287, 288 dipole of, 288 in alkali metal halides, 95 vs. covalent, 287 Ionic character, 287 Ionic crystal, 81, 311 Ionic radius, 355 Ionic solids, 79, 81, 311 electrical conductivity, 80 properties of, 312 solubility in water, 79 stability of, 311... 

The ionic conductivity of alkali-metal chloroaluminates was also investigated by Weppner and Huggins [37] but also only in the temperature range between room temperature and just above the melting point. At room temperature the ionic conductivity... 

The alkali metals also release their valence electrons when they dissolve in liquid ammonia, but the outcome is different. Instead of reducing the ammonia, the electrons occupy cavities formed by groups of NH3 molecules and give ink-blue metal-ammonia solutions (Fig. 14.14). These solutions of solvated electrons (and cations of the metal) are often used to reduce organic compounds. As the metal concentration is increased, the blue gives way to a metallic bronze, and the solutions begin to conduct electricity like liquid metals. 

The permeability tests for alkali metal ions in the aqueous solution were also conducted. When an aqueous salt solution moves to cell 2 through the membrane from cell 1, the apparent diffusion coefficient of the salt D can be deduced from a relationship among the cell volumes Vj and V2, the solution concentration cx and c2, the thickness of membrane, and time t6 . In Table 12, permeabilities of potassium chloride and sodium chloride through the 67 membrane prepared by the casting polymerization technique from the monomer solution in THF or DMSO are compared with each other and with that the permeability through Visking dialyzer tubing. The... 

In conclusion, polymer electrolytes based on phosphazene backbone and containing ether side chains are, after complexation with alkali metal salts, among the highest ionically solvent-free polymer salt complexes, with conductivities in the order of 10" -10" S cm However, these conductivities are still below the value of 10 S cm" which is considered to be the minimum for practical applications. Therefore the design of new polyphosphazenes electrolytes with a higher conductivity and also a higher dimensional stability still remains a challenge for future researchers. 

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