Tetramethyl ammonium hydrate

Tetramethyl ammonium hydrate—(CH,) N,OH—91. -This substance, whose constitution is similar to that of ammonium hydrate, is obtained by decomposing the corresponding iodide, (CHJ NI, formed by the action of methyl iodide upon trimethylamine. It is a cr -stalline solid deliquescent veiy soluble in H,0 caustic not volatile without decom-position. It attracts carbon dioxide from the air, and combines witli acids to form crystallizable salts. 

It is probable that a primary reason for the lower stability of complexes formed between dicyclohexyl-18-crown-6 and cations larger than the optimum size (e.g. Cs+) is that these cations are too large to "fit into the ligand cavity. On the other hand, as cation size decreases from that affording maximum stability, the hydration energy of the cation becomes predominant and little or no reaction is found, as in the case of Ca2+. Very large cations such as di, tri, and tetramethylammo-nium and trimethyl sulfonium do not appear to form complexes wi h dicyclohexyl-18-crown-6 in aqueous solution (4). Also, tetramethyl-ammonium ion (radius = 3.47 A (30)) complexes less strongly (log K =... 

McMullan RK, Mak TCW, Jeffrey GA (1966) Polyhedral clathrate hydrates XI. Structure of tetramethyl ammonium hydroxide pentahydrate. J Chem Phys 44 2338-2345... 

NaAl,K2NO SiuC4H 2 7H20, Potassium sodium tetramethyl ammonium aluminum silicate hydrate, 22 65... 

NaAl4K2N026Sil4C4H 2 7H20, Potassium, sodium tetramethyl ammonium aluminum silicate hydrate, 22 65 NaBNC2H, Borate(l-), cyanotri[(W)-hydro]-, sodium, 21 167 NaCo02, Sodium cobalt oxide, 22 56 NaF6U, Uranate(V), hexafluoro-, sodium, 21 166... 

Hydrates with related clathrate-like structures are formed by tetramethyl and tetraethyl ammonium salts. The tetramethyl and tetraethyl ammonium salts form hydrates in which the cations occupy voids in hydrogen-bonded structures formed by the anions and the water molecules. Unlike the gas hydrates, the alkylamine hydrates, and the butyl and isoamyl ammonium salt hydrates discussed in the next section, these cage-like structures do not feature the pentagonal dodecahedron as a common structural component. 

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