Antimony structure

A comparison of 160 and 100 is also instructive. The former contains two more electrons than the latter (Te2 vs. Sb2) and this results in quite different structures being adopted, with the tellurium structure more open than the antimony structure (i.e., less M—E bonds). 

Kaiser B, Bernhardt T M, Kinne M, Rademann K and Fleidenreich A 1999 Formation, stability, and structures of antimony oxide cluster ions J. Chem. Phys. 110 1437... 

Arsenic dissolves in concentrated nitric acid forming arsenicfV) acid, H3ASO4, but in dilute nitric acid and concentrated sulphuric acid the main product is the arsenic(III) acid, HjAsOj. The more metallic element, antimony, dissolves to form the (III) oxide Sb O, with moderately concentrated nitric acid, but the (V) oxide Sb205 (structure unknown) with the more concentrated acid. Bismuth, however, forms the salt bismulh(lll) nitrate Bi(N03)3. 5H,0. 

Fig. 4. Grain structure of lead—2 wt % antimony alloy battery grid at a magnification of 50x (a) no nucleants (b) containing 0.025 wt % selenium as a grain...

Alloys of antimony, tin, and arsenic offer hmited improvement in mechanical properties, but the usefulness of lead is limited primarily because of its poor structural qualities. It has a low melting point and a high coefficient of expansion, and it is a veiy ductile material that will creep under a tensile stress as low as 1 MPa (145 IbFin"). 

Figure 7.6. A filled. skutterudite antimonide crystal structure. A transition niclal atom (Fc or Co) at the centre of each octahedron is bonded to antimony atoms at each corner. The rare earth atoms (small spheres) are located in cages made by eight octahedra. The large thermal motion of rattling of the rare earth atoms in their cages is believed be responsible for the strikingly low thermal conductivity of these materials (Sales 1997).

Radical cations can be derived from aromatic hydrocarbons or alkenes by one-electron oxidation. Antimony trichloride and pentachloride are among the chemical oxidants that have been used. Photodissociation or y-radiation can generate radical cations from aromatic hydrocarbons. Most radical cations derived from hydrocarbons have limited stability, but EPR spectral parameters have permitted structural characterization. The radical cations can be generated electrochemically, and some oxidation potentials are included in Table 12.1. The potentials correlate with the HOMO levels of the hydrocarbons. The higher the HOMO, the more easily oxidized is the hydrocarbon. 

Section 313 requires emissions reporting on the chemical categories listed below, in addition to the specific chemicals listed above. The metal compounds listed below, unless otherwise specified, are defined as including any unique chemical substance that contains the named metal (i.e., antimony, copper, etc.) as part of that chemical s structure. 

Consistent with this, dissolution of KF increases the conductivity and KIFe can be isolated on removal of the solvent. Likewise NOF affords [NO]+[IF6] . Antimony compounds yield ISbFio, i-2. [IF4]+[SbF6], which can be titrated with KSbFfi. However, the milder fluorinating power of IF5 frequently enables partially fluorinated adducts to be isolated and in some of these the iodine is partly oxygenated. Complete structural identification of the products has not yet been established in all cases but typical stoichiometries are as follows ... 

Pretreating the feedstocks with hydrogen is not always effective in reducing heavy metals, and it is expensive. Other means that proved successful are modifying the composition and the microporous structure of the catalyst or adding metals like Sb, Bi or Sn, or Sb-Sn combination. Antimony organics have been shown to reduce by 50% gas formation due to metal contaminants, especially nickel. ... 

Prengaman, R. E., Structure Control of Non-Antimonial Lead Alloys via Alloy Additions, Heat Treatment and Cold Working, Pb80, Ed. Proc. 7lh Ini. Lead Conf., Madrid, Lead Development Association, London (1983)... 

When specimens of pure lead and a 5% antimony alloy were periodically oxidized and reduced, lead oxide layers were observed with different structures ... 

Antimony, tris(ethyldithiocarbonato)-stereochemistry, 1,82 structure, 1,82 Antimony, tris(oxalato)-stereochemistry, 4, 82 structure, 1, 82... 

The radii in the lowest row of the table were obtained by a number of approximate considerations. For instance, if we assume the bismuth radius to bear the same ratio to the interatomic distance in elementary bismuth as in the case of arsenic and antimony, we obtain (Bi) = 1.16— 1.47 A. A similar conclusion is reached from a study of NiSb and NiBi (with the nickel arsenide structure). Although the structures of the aurous halides have not been determined, it may be pointed out that if they are assumed to be tetrahedral (B3 or Bi) the interatomic distances in the chloride, bromide, and iodide calculated from the observed densities1) are 2.52, 2.66, and 2.75 A, to be compared with 2.19, 2.66, and 2.78 A, respectively, from pur table. 

Especially notable is also the synthesis and structural characterization of an unusual antimony(III) guanidinate. 1,2,3-Tiiisopropylguanidine, Pr N = C(NHPr )2,was found to react with 1 molar equivalent of Sb(NMe2)3 in toluene under formation of a yellow solution, from which the novel compound Sb[Pr NC(NPr )2][Pr NHC(NPr )2] could be isolated in 10% yield as highly air-sensitive crystals. In the solid state, the complex adopts a heavily distorted trigonal-bipyramidal molecular structure in which the Sb is chelated by a [CfNPr ls] dianion and a [Pr NHC(NPr )2] monoanion (Figure 16). Supramolecular... 

In the early 1950s, in a systematic study, Donges (106-108) discovered most of the chalcogenide halides of antimony and bismuth that are known today, and then solved their structures. 

Keywords Aluminum, Gallium, Antimony, Bismuth, Structures... 

In molecules in which the nitrogen atom is at a bridgehead, pyramidal inversion is of course prevented. Such molecules, if chiral, can be resolved even without the presence of the two structural features noted above. For example, optically active 12 (Trdger s base) has been prepared. Phosphorus inverts more slowly and arsenic still more slowly." Nonbridgehead phosphorus," arsenic, and antimony compounds have also been resolved... 

Jain VK, Bohra R, Mehrotra RC (1982) Structure and Bonding in Organic Derivatives of Antimony(V). 52 147-196... 

Lighter elements show a stronger tendency to develop a stereochemically active lone pair than their heavier homologues. For instance, for antimony(III) more distorted structures are known than for bismuth(III) ]29]. 

The binary chalcogenides of antimony and bismuth are highly colored compounds that are readily prepared by direct reaction of the elements at 500-900 C. They have rather complex ribbon or layer structures and exhibit semiconductor properties. 

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