Polyatomic Cations of Group

The discovery of bismuth polycations arose out of an investigation into the nature of Bid , first prepared by reduction of bismuth trichloride by bismuth metal by Eggink (110) in 1908. More recently, Hershaft and Corbett (109), obtained black crystals of this material from the melt and by single crystal X-ray diffraction showed that the unit cell contained 4Bi9 , 8BiClg , and 2Bi2Cl8 , i.e., it has the empirical composition BigCl7. Recently the cation Big has also been 

Bjerrum and Smith have established the identity of Bi, Big (IIS, 114), and Big (115) in fused salts. The formulas Bi and Big were determined by studying the equilibria (41)-(43). Equilibrium 

Antimony metal has been oxidized by arsenic pentafluoride (122) to the compoimd SbAsPe according to Eq. (45). 

The compound SbAsFg may contain the (Sb+) cation, but it would be difficult on the basis of analysis alone to rule out other stoichiometries such as Sbg (AsFe )4 where the antimony is in an oxidation state close to but not equal to -1-1. 

Metallic antimony dissolves slowly in fluorosulfuric acid (123) at room temperature according to Eq. (46) to give the compound SbSOgF which has been isolated as a pure solid. 

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In this section, the polyatomic cations of group 17 elements (halogen and interhalogen cations and polycations), cations and polycations of group 16 elements (O, S, Se, and... 

Polyatomic species containing atoms from group IVA are produced by reducing the elements in liquid ammonia that contains some dissolved sodium. In accord with the hard-soft interaction principle (see Chapter 9), isolation of species containing large anions is best accomplished when a large cation of... 

A more elaborate hybrid method is that devised by Leontyev et al.,143,144 which was described in Section III.3. For a group of polyatomic cations, the computed Gcicctrostati(. was found to be within an absolute average of 1.5 kcal/mole of the experimental values (the latter were extracted from measured AGsolvation) 144 for three polyatomic anions, the deviation was 5.7 kcal/mole. (The range was -57.1 to -100.4 kcal/mole.) It was concluded that the anions require separate parametrization. 

The apparent Instability of homopolyatomic anions of elements to the left of group IV (and of polyatomic cations to the left of group V) Is thought to result from a deficiency of bonding electrons In species where the principal bonding Is considered to originate largely from p-type orbitals. The electron deficient polyboranes, with which these clusters have... 

The name of the electropositive constituent is simply the unmodified element name, the name of a polyatomic cation or an accepted group name, as appropriate. 

Reaction of group 15 elements like arsenic with alkali or alkaline earth metals forms Zintl anions of the general type Asn". Characterization of these species has been accomplished dissolving the solids in liquid NH3 or ethylenediamine (H2NCH2CH2NH2) and adding the macrocycle, 2,2,2-crypt (5) to complex the cations and stabilize the polyatomic anions. The fully characterized Zintl arsenic anions As4, As and Asu are shown inFigme 1. ... 

The preparation and properties of homopolyatomic cations of the Group VI elements have been reviewed recently.1 The general method described below, involving the oxidation of elemental sulfur, selenium, and tellurium with either antimony pentafluoride or arsenic pentafluoride in liquid sulfur dioxide, is convenient for the preparation of compounds containing these polyatomic cations. The procedure is basically that briefly described previously2 for the preparation of Se8(Sb2F j i )2. 

Ions aren t always monoatomic, composed of just one atom. Ions can also be polyatomic, composed of a group of atoms. For example, take a look at Table 6-3. Notice an3rthing about the Mercury(I) ion Its ion symbol, Hg2 shows that two mercury atoms are bonded together. This group has a 2+ charge, with each mercury cation having a 1+ charge. The mercurous ion is classified as a polyatomic ion. 

STEP 1 Calculate the total number of valence electrons for the molecule by summing the nnmber of valence electrons (= group number) for each atom. If you are writing the Lewis formula of a polyatomic anion, you add the number of negative charges to this total. (For C03 you add 2 because the 2- charge indicates that there are two more electrons than are provided by the neutral atoms.) For a polyatomic cation, you subtract the number of positive charges from the total. (For NH4 you subtract 1.)... 

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