Pn cages

Jnst as the cages Py and Pio are derivatives of the tetrahedral P4 molecule, the Pn cage, characteristic for the M3P11 alkali metal phosphides, is a derivative of the... 

All other homoatomic Pn cluster anions are cage molecules with localized two-center-two-electron bonds. The cyclic [PnJ anion has been characterized by NMR spectroscopy for Pn = P [210], and structures are known for Pn = P, As, Sb, Bi (Table 2). A planar [Ps] anion has only been detected in solution by P NMR spectroscopy [210]. Envelop-shaped five- and six-membered rings are found for [Pns] and [Pe]", whereas [Asg]" deviates only slightly from planarity and has a chair conformation. The aromaticity of the planar anions [P4] and [Pe]" is distinct from that of regular 671-aromatic hydrocarbons and has been described... 

The M3P11 phases transform into plastically crystalline modifications like the M3P7 phases. In the high-temperature form (/3), the phosphides match the structure of the intermetallic Li3Bi. The Bi positions are surrounded by the cages of P and Pn with orientational disorder. 

The caged [Co(pn)3] complexes, leh and 063 [Co(diAm-pnsar)] , have a marked dependence of Dq on the conformation, the lela complex has a typical value (2240 cm" ), whereas the 063 complex is greenish-yellow and has a Dq of 2380 cm (150). The capping of the faces of the complexes in this case leads to a dramatic increase in ligand field strength for the oba complex. 

The group 1 and 2 metals form compounds M3P and M3P2 respectively, which are hydrolysed by water and can be considered to be ionic. The alkali metals also form phosphides which contain groups of P atoms forming chains or cages, the cages being either [Pv] (15.18) or [Pn] (15.19). Lithium phosphide of stoichiometry LiP consists of helical chains and is better formulated as Li [P ], the [P ]" ... 

Bassindale AR, Liu Z, MacKinnon lA, Taylor PG, Yang Y, Light ME, Horton PN, Hursthouse MB (2003) A higher yielding route for T8 silsesquioxane cages and X-ray crystal structures of some novel spherosilicates. Dalton Trans (14) 2945. doi 10.1039/b302950f... 

Bassindale AR, Parker DJ, Poumy M, Taylor PG, Horton PN, Hursthouse MB (2004) Fluoride ion entrapment in octasilsesquioxane cages as models for ion entrapment in zeolites. Further examples. X-ray crystal structure studies, and investigations into how and why they may be formed. Organometallics 23(19) 4400 405. doi 10.1021/0m049928g... 

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