Crystal stoichiometric

Insulator, crystal (stoichiometric) Neodymium UP(NdPgO 1052 Flashlamp... 

INTRODUCTION This data sheet contains information for single crystal stoichiometric titanium dioxide. 

Equations that describe co-crystal solubility dependence on [H ], Kgp, and for several types of co-crystals have been derived and are presented in Table 11.1. The interested reader is directed to the original pubhcation for the full derivations. " These equations describe the co-crystal stoichiometric solubi-Uty, when co-crystal is in equihbrium with solutions of stoichiometry equal to the co-crystal. 

Figure 11.6 Dependence of co-crystal solubility or drug concentration, [R]x, on coformer concentration, [A]x, and pH for a 1 1 RHA co-crystal calculated from equation (11.13) with Asp = l mM and co-former pA a = 3.0. Solubility of drug, Sr, is represented by the yellow surface (Sr = 2 mM) and co-crystal by the blue/green surface. The pH value at the intersection of the drug and co-crystal stoichiometric solubility curves corresponds to pHmax where a solution of stoichiometric composition is in equilibrium with two solid phases, co-crystal and drug. Reprinted with permission from Bethune et al., ref. 34. Copyright 2009 American Chemical Society.

Aeu dependence on external conditions is critical to establish co-crystal thermodynamic stability. For instance, > 1 for a 1 1 co-crystal or A eu >0.5 for a 2 1 co-crystal indicates that the co-crystal is thermodynamically unstable with respect to the drug. A decrease of below the co-crystal stoichiometric ratio, for example, < 1 for a 1 1 co-crystal or <0.5 for a 2 1 co-crystal indicates a reversal in the thermodynamic stability, where the co-crystal is more stable... 

The relationship between. Keu and a, for carbamazepine co-crystals in aqueous solutions with different pH values and in several organie solvents is shown in Figure 11.16. The data points represent. Keu values and solubilities obtained from measured eutectic solution concentrations of eo-crystal components according to equations (11.40) and (11.42). Co-crystal stoichiometric solubilities increase relative to drug solubility as the [eo-former]eu increases relative to the [drugjeu- Other eo-crystal stoichiometries and solution equilibria are presented in the original publication. ... 

Cd2P 2Sg mono- clinic a= 6.17 6=10.67 c= 6.82 iS= 107.1° Z=2 eexp = 3.49 ex = 3.71 Fe2P2Sg-type. X, single crystal. Stoichiometric mixtures of the elements heated at 600 -670°C for 1 week in evacuated quartz ampoules. Yellow hexagonal platelets. 73Klil, 70Klil )... 

Cu3GaSe4Tl2 I4/mmm a= 4.0031 c= 13.7062 c/a=3A2 Z=1 ex = 7.45 Cu2TlSe2-type. X, single crystal. Stoichiometric amounts of the binary selenides were fused and annealed at 300 °C for several days. Platelets, bluish grey. 79Brul... 

Since the reactive gas in the RE process is in a molecular state and thus less likely to react with the vapor species, the formation of a well crystallized stoichiometric film requires high thermal activation at the substrate. This problem becomes acute in situations where the reactive gas consists of more than one element. The typical examples are S1H and CH CgHg for the formation of silicides and carbides respectively. The concept of electron impact ionization and excitation of the reactive gas in the substrate-source space, as introduced by Bunshah and Raghuram solved this problem. The ionization and excitation of the gas activates the compound forming reactions and the compound films can be synthesl2 d at a much lower substrate temperature. This process is known as Activated Reactive Evaporation (ARE). 

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