The new perovskite PbVO 3 was synthesized under high-temperature and high-pressure conditions. Its crystal structure (a ) 3.80005(6) Å, c ) 4.6703(1) Å, Z ) 1, S.G. P4mm) contains isolated layers of corner-shared VO 5 pyramids, which are formed instead of octahedra due to a strong tetragonal distortion (c/a ) 1.23). The lead atom is shifted out of the center of the unit cell toward one of two [VO 2 ]-layers due to the influence of the lone pair. This new perovskite exhibits a semiconductor-like F(T) dependence down to 2 K. This behavior can be qualitatively explained by taking into account strong electron correlations in electronic structure calculations.

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The electrical resistance of single-wall carbon nanotubes (SWNT) produced by condensation of a laservaporized graphite/Ni/Co mixture at 1200 • C was studied under quasihydrostatic pressures up to 90 kbar. The resistance exhibits a positive temperature coefficient, characteristic of a metal, up to 10 kbar, whereas the absolute value decreases abruptly by a factor ≈ 10. From 10-30 kbar R increases with pressure and the TCR becomes negative. At still higher pressure, up to 90 kbar, R decreases gradually with pressure, similar to the case of graphite. Raman scattering and electron microscopy performed after 25-kbar pressurizations indicate that the SWNT and its lattice are preserved. We propose that the sequential behavior of R(P) reveals in turn the processes of compaction, defect formation by kinking, and finally the van der Waals compression of the inter-tube spacing in the triangular lattice.

This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting galley proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. [a] Cameron Black, [b] Lewis J. Downie [b] , Dmitry E. Sklovsky [a, c] , Peter S.Berdonosov [a] , Andrei V. Olenev [a, c] , Wuzong Zhou [b] , Philip Lightfoot [b] and Valery A.Dolgikh [a] similarities to those of known selenite analogs. We discuss the trends in similarities and differences in compositions and structural details between the Se and Te compounds; more members of the family are predicted.

LiC,, the super dense high-pressure phase o f lithium-intercalated graphite, has been tested i n a two-electrode cell vs. Li with an organic electrolyte. A primary capacity o f 910 rnAh/g per carbon atom was observed during the first deintercalation cycle at constant current, almost three times greater than the ideal 372 mAh/g value for the normal saturatedphase LiC,. LiC, also exhibited the desirable characteristic o f a low and flat working voltage profile, and most o f the Li was removed at -18 mV. The first deintercalation cycle also showed weak anomalies which coincide with previously identified phase transitions between high order Li in-plane superlattices. Repeated cycling yielded a reversible capacity close t o 372 mAh/g, with Li removed at -100 mV. The high initial capacity and near ideal reversible secondary capacity suggests that this material could b e useful i n rechargeable batteries requiring a very large first deintercalation capacity.