Binary cluster anions

There are several kinds of cluster ions, both cations and anions, observed in mass spectrometers. There are bare metal cluster cations and anions, binary clusters cations and anions M Em (where E is an element such as O or S), and other clusters involving ligands and metals. In this section, the bare metal cluster cations Mj and anions M will be discussed separately followed by the binary cluster cations M E+, then binary cluster anions M E , and finally other cluster systems having more than one metal atom. 

Metal oxide and sulfide clusters form the bulk of the reactivity studies of binary cluster anions. 

Smaller tetrel element clusters like the tetrahedral [E4] ions were observed for the first time in the alloy NaPb [38] and are present in AE phases for E = Si to Pb and A = Na-Cs. Although these phases are not soluble, ammoniates of [Pb4]" have been obtained from liquid ammonia solutions of the binary phase RbPb [39]. The Zintl phases Ai2Sii7 (A = K, Rb, Cs) and KgRb6Sii7, which in the solid state contain [Si4]" and [Sig]" anions in the ratio 2 1, readily dissolve in liquid ammonia, and recently it has been shown that both cluster anions [Si4]" [37] and [Sig]" [40] are retained in solution. Corresponding pentel element clusters in bulk solids are [Pn7] and [Pnn] (Table 1). 

Bernhardt TM, Socaciu-Siebert LD, Hagen J, Woste L (2005) Size and composition dependence in CO oxidation reaction on small free gold, silver, and binary silver-gold cluster anions. Appl Catal A Gen 291 170... 

X neutral binary clusters cluster anions + neutral hydride clusters anionic hydride clusters... 

In solvate crystals obtained from liquid ammonia and ethylenediamine germanium, nido- Ge9] clusters were found together with naked K or Rb and Rb or Cs cations, respectively [37, 38], in which all cations were coordinated to the cluster anions in numerous contacts, resulting in a three-dimensional (3-D) network very similar to that in the binary intermetaDic phases. The solvent molecules in the lattice are attached to the alkaU metal atoms, but the compounds A+Geg(en) (A = Rb, Cs) lose their ethylenediamine easily upon heating, thereby leaving A+Geg [38]. 

An elegant access to larger cluster units is to make use of preformed smaller clusters as they occur, e.g., in Zintl phases [8, 9]. The phase KSi (or K4Si4) contains homoatomic Si4 tetrahedra, and thus a salt-like formulation (Na )4[Si4]" with a formal electron transfer is appropriate (Fig. 1) [10]. Such homoatomic anionic building blocks occur in binary or ternary intermetallic phases A E and A Pn j with A being an alkali and alkaline-earth metal, and E = Si-Pb and Pn = P-Bi. These phases are generally available in good quantities, and - since a few members... 

Soluble heptapnicanortricyclane anions [Pny] (Fig. 3a) and trishomocubane-shaped (ufosane-like) anions [Pnn] (Fig. 3d) are very common and known as in the binary solids for Pn = P, As, Sb (Table 2). Oxidative coupling of these monomers leads to the dimers [Pny-Pny]" and [Pnn-Pnn]" for Pn = P and As (Fig. 3b, e), which - as observed for the tetrel element clusters - have an external homoatomic bond, but in this case the structures of the monomeric units are fully retained upon dimerization. A trimeric oxidative coupling product of [Py] is the... 

Germanes hydride, 2 76 reactivity of, 2 87 Germanium anionic cluster, 24 227 azides, preparation, 9 138 properties, 9 135-136, 139, 141 binary carbide not reported, 11 211 carbides, preparation of, 11 163 chalcogenide halides, 23 390 chlorides, mass spectra of, 18 248, 249 complexes, xenon fluoride reactions, 46 85 compounds, see also Organogermanium compounds... 

Although the products are written as simple ionic binary compounds, it is known that complex materials containing anions that consist of polyhedral species containing the nonmetal are also produced. For example, a P73- cluster is known, which has six of the phosphorus atoms arranged in a trigonal prism with the seventh occupying a position above the triangular face on one end of the prism. 

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