Preparation high pressure synthesis

Finally, the high-pressure synthesis favors the formation of borides that are difficult to prepare under standard conditions. In this way SmBj with the AlB2-type structure and GdB,2 and ThB,2 with the UB,2-type structure are prepared. ... 

This paper consists of three parts. The first part describes the high pressure synthesis of bimetallic compounds of NbN and MN where M is a Group 13 metal such as Al, Ga, or In. The second part discusses crystal structure investigations of a series of alkaline earth and transition metal nitrides, carried out to understand the bonding surrounding the transition metals. The third part describes the preparation of new metastable transition metal nitride and their solid solutions by rf-sputter deposition. 

In this class of binary compounds, a new tetragonal form of boron sulfide B2S3 prepared by high-pressure synthesis is noteworthy. Remarkably, instead of a simple structure related to that of normal ambient pressure form of B2 S3, it contains two kinds of supertetrahedra built up from 20 and 34 adamantane-type superclusters to form an elaborate three-dimensional framework (Figure 4) These supertetrahedra are linked to each other in a unique way forming an interpenetrating zinc-blende-type structure. This compound is a wide band-gap semiconductor with an energy gap of 3.7 eV. 

As an alternative to the high-pressure synthesis, crystalline B2O3-I can tilso be prepared by the stepwise dehydration of orthoboric acid (H3B03>[164] or by seeding a melt withborophosphate [165]. 

Sorbitol is a sweetener often substituted for cane sugar because it is better tolerated by dia betics It IS also an intermediate in the commercial synthesis of vitamin C Sorbitol is prepared by high pressure hydrogenation of glucose over a nickel catalyst What is the structure (including stereochemistry) of sorbitoP... 

Kolbe-Schmitt reaction (Section 24 10) The high pressure re action of the sodium salt of a phenol with carbon dioxide to give an o hydroxybenzoic acid The Kolbe-Schmitt reac tion IS used to prepare salicylic acid in the synthesis of as pinn... 

Low Oxidation State Chromium Compounds. Cr(0) compounds are TT-bonded complexes that require electron-rich donor species such as CO and C H to stabilize the low oxidation state. A direct synthesis of Cr(CO)g, from the metal and CO, is not possible. Normally, the preparation requires an anhydrous Cr(III) salt, a reducing agent, an arene compound, carbon monoxide that may or may not be under high pressure, and an inert atmosphere (see Carbonyls). 

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