Rock-salt phase

The rock-salt phase is a stable phase of nitrides at elevated pressures. The phase transition pressures are 370 - 520 kbar for GaN [6,15], 120 kbar for InN [6] and 230 kbar for AIN [5],... 

Bulk modulus has been calculated from first principles by a local-density approximation [19] and by a linear muffin-tin orbital method [10], suggesting a value B = 165 GPa. Measurements of bulk modulus in high-pressure induced rock salt phase yielded 170 GPa [20]. 

IR and Raman spectra were used to characterise GaN nanocrystals grown by chloride-hydride vapour-phase epitaxy on oxidised silicon.138 High-pressure Raman spectroscopy was used to follow the wurtzite to rock salt phase transition for epitaxial GaN.139 The Raman spectrum of prism-shaped GaN nanorods included characteristic bands at 255 and 419 cm-1.140 Raman spectroscopy was used to characterise GaNi xPx alloys.141 143... 

Sato et al. [3] also reported that the oxide residue obtained on thermal decomposition of the Mg-Al HT below 1373K comprises a defect rock salt phase, Mgi-xAhx/a oO. 

TiO Formula weight 127.80. Gtolden yellow powder. M.p. 1750°C d 4.89. Crystal structure type B1 (NaCl type). The rock salt phase is homogeneous over a wide range of compositions (TiOi g-TlOo.e). TIO dissolves in dilute hydrochloric and sulfuric acids with partial oxidation Tl + H+ = TI + Vs Hg. 

The gap of p-BN increases upon volume compression as in the case of diamond, while in most semiconductors the reverse is true [4]. This is due to the fact that boron and nitrogen atoms have deep and localized pseudopotentials as compared with the atoms of other rows of the periodic table. It can be calculated [5] by the same technique described in [4] that at very high pressures boron nitride should favor the rock salt phase, while the p-BN structure is unstable even at highly compressed volumes [5]. Calculations using a nonlocalized pseudopotential model lead to a band gap of 4.41 eV for p-BN for further details, see [6]. Electronic properties of p-BN have been derived by ab initio, norm-conserving, nonlocal pseudopotential... 

Perlin P, Jauberthie-Catillon C, Itie JP et al (1992) Raman scattering and X-ray absorption spectroscopy in gallium nitride under high pressine. Phys Rev B 45 83-89 Xia H, Xia Q, Ruoff AL (1993) High-pressure structure of gallium nitride wurtzite-to-rock-salt phase transition. Phys Rev B 47 12925—12928... 

Other aging mechanisms trigger a change in the crystalline stmcture of the positive electrode s active material at the interface with the electrolyte. The active material, particularly in the case of a layered oxide, can serve as a source of oxygen for the electrolyte s oxidation reactions. A layer then forms at the extreme surface of the active material, made up of a rock salt phase deficient in lithium and oxygen (Figure 2.10). 

Redo, J.M., Blanco, M.A., Luana, V., Pandey, R., Gerward, L. and Staun Olsen, J. (1998) Compressibility ofhigh-pressure rock salt phase of ZnO. Physical Review B Condensed Matter, 58, 8949. 

Amatucci et al [46,47] have demonstrated that the capacity fade in the 4-V range of Lii [Mn2]04 occurs primarily at the end of discharge. A poor Li-ion mobility results in a build-up of the tetragonal Li2.8[Mn2]04 phase at the surface at the end of discharge, and the high Mn -ion concentration in this phase allows it to be attacked by any HF in the electrolyte via a surface disproportionation reaction 2Mn = Mn + Mn foUowedby Mn dissolution into the electrolyte. As a result, the rock-salt phase Ii2Mn03 is also formed at the surface [48]. In... 

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