Corrigendum to “Condensed species in Titan's stratosphere: Confirmation of crystalline cyanoacetylene (HC3N) and evidence for crystalline acetylene (C2H2) on Titan” [Icarus 178 (2005) 165–170]

Icarus ◽  
2007 ◽  
Vol 186 (2) ◽  
pp. 589
Author(s):  
R.K. Khanna
Keyword(s):  
Condensed Species

Influence of condensed species on thermo-physical properties of LTE and non-LTE SF6–Cu mixture

2017 ◽  
Vol 50 (41) ◽  
pp. 415203 ◽  
Author(s):  
Zhexin Chen ◽  
Yi Wu ◽  
Fei Yang ◽  
Hao Sun ◽  
Mingzhe Rong ◽  
...  
Keyword(s):  
Physical Properties ◽  
Thermo Physical Properties ◽  
Condensed Species

Condensation in Solution: Polycations and Polyanions

2019 ◽  
Author(s):  
Jean-Pierre Jolivet
Keyword(s):  
Coordination Number ◽  
Molecular Species ◽  
Condensation Reaction ◽  
Second Step ◽  
Anionic Complex ◽  
Step Process ◽  
Monomeric Complex ◽  
Leaving Group ◽  
Electrically Charged ◽  
Condensed Species

Condensation of metal complexes in solution forms entities in which the cations are linked by hydroxo (HO−) or oxo (O2−) bridges. The reaction is initiated by the addition of a base to an aquocomplex: . . . 2[Cr(OH2)6]3++ 2HO- → [Cr2(OH)2(OH2)8]4+ + 2 H2O . . . or by the addition of an acid to an anionic complex: . . . 2 [CrO4]2- + 2H+ → [Cr2O7]2- + H2O . . . Thus, purely aquo- and purely oxocomplexes are stable in solution, and the condensation of cations is initiated by hydroxylation. With regard to electrically charged hydroxylated complexes, the reaction forms discrete and soluble entities—polycations and polyanions with a molecular complexity which depends on acidity conditions. This chapter presents a detailed study of their formation and structure. With regard to noncharged hydroxylated complexes, the condensation reaction is no longer limited and leads to the formation of a solid (a subject that is examined in the following chapters). The hydroxylation reaction is the key stage to initiate the condensation of cations in solution. It is thus important to precise the mechanism of the successive steps of the process, in order to understand why the behavior of a cation is closely related to its oxidation state, and why the reaction product may be a discrete molecular species or a solid. As a cation generally exhibits its maximum coordination number in the initial monomeric complex and in condensed species, the condensation reaction is a substitution that proceeds according to one of three basic mechanisms: dissocia­tion, association, and interchange or direct displacement [1, 2]. Dissociative substitution is a two-step process involving the formation of a reduced-coordination intermediate: In the first step, a labile ligand, the leaving group, breaks its bond in the starting complex before a nucleophilic entering group completes, in the second step, the cation coordination (Fig. 3.1 a). Associative substitution is also a two-step process in which the intermediate temporarily has increased coordination. The bond with the nucleophilic entering group (first step) occurs prior to the release of the leaving group (second step) (Fig. 3.1 b).

scholarly journals The Atmospheres of Substellar-Mass Objects

2000 ◽  
Vol 197 ◽  
pp. 505-511
Author(s):  
Adam Burrows
Keyword(s):  
Alkali Metals ◽  
Brown Dwarf ◽  
Jovian Planets ◽  
The Masses ◽  
Condensed Species

Between the masses of the Jovian planets and the stars, a new population of exotic substellar-mass objects (SMOs) is now being discovered in profusion, that are challenging our notions of what a planet, brown dwarf, or star can be. I focus on some exotic and distinctive aspects of the compositions of SMO atmospheres. In particular, I review the formation of silicate, water, and ammonia clouds, the role of rainout in altering the abundance of the alkali metals, and the suppression by atomic potassium of the optical fluxes of a methane dwarf such as Gliese 229B. Furthermore, I discuss the order in which various molecular, atomic, and condensed species might dominate or influence SMO atmospheres, with an eye to anchoring new spectral classes from Teff ~ 2000 K to ~ 100 K.

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