Water in the Solid State

As is pointed out in the introduction to Section II, the presence or absence of water in the solid state gives no indication as to whether or not covalent hydration occurs in aqueous solution. However, many examples are known of substances which hydrate strongly in solution and also in the solid state. Thus, 2-hydroxy- and 6-hydroxy-pteridine crystallize with one molecule of water. On heating, the former loses water rapidly only at 180°, whereas the latter retains all of the water up to 180° where it begins to darken. ... 

Water in the solid state forms mixtures that are very sensitive to impact with liquid fluorine, which, if they detonate, have the same disruptive property as trinitrotoluene. If water is in the liquid state, the explosion is instantaneous and equally violent. 

Beryllium(II) is the smallest metal ion, r = 27 pm (2), and as a consequence forms predominantly tetrahedral complexes. Solution NMR (nuclear magnetic resonance) (59-61) and x-ray diffraction studies (62) show [Be(H20)4]2+ to be the solvated species in water. In the solid state, x-ray diffraction studies show [Be(H20)4]2+ to be tetrahedral (63), as do neutron diffraction (64), infrared, and Raman scattering spectroscopic studies (65). Beryllium(II) is the only tetrahedral metal ion for which a significant quantity of both solvent-exchange and ligand-substitution data are available, and accordingly it occupies a... 

Water is a very structurally versatile molecule. Water exists in all three physical states solid, liquid, and gas. Under extremely high temperature and pressure conditions, water can also become a supercritical fluid. Liquid water can be cooled carefully to below its freezing point without solidifying to ice, resulting in two possible forms of supercooled water. In the solid state, 13 different crystalline phases (polymorphous) and 3 amorphous forms (polyamorphous) of water are currently known. These fascinating faces of water are explored in detail in this section. 

Ethylenebisbiguanidesilver(III) sulfate forms red, silky crystals which are sparingly soluble in water. In the solid state it can be heated to 30° without appreciable decomposition. A solution Of the pure substance in water or dilute sulfuric acid can be heated on the water bath without any detectable change. In concentrated sulfuric acid it dissolves to form a red solution. The salt remains unchanged... 

Many naturally occurring ionic polysaccharides are mixed salts of alkali, alkali-earth, and transition metals with different insolubilities. Salts of alkali metals are invariably soluble. Sodium, the most ubiquitous alkali, possesses a single valence electron, large atomic and ionic radii, and very low ionization potential. Na+ hydrates in aqueous solution and retains its coordination water in the solid state. Prior to use, native polysaccharide salts are usually converted to the sodium form whence they acquire functionality. 

In an early study by Lehn et al., it was also demonstrated that quaterpyridine (36) forms a monomeric copper(I) species (that is not helical), whereas with cop-per(II) a dimeric species is obtained these complexes may be interconverted elec-trochemically. The above monomeric copper(I) complex was shown by X-ray diffraction to have a tetragonal pyramidal structure [four basal nitrogens and an axial oxygen (water)] in the solid state. This ligand also yields a dinuclear complex with ruthenium(II) of type [Ru2L2] . ... 

Saleki-Gerhardt, A. Role of Water in the Solid-State Properties of Crystalline and Amorphous Sugars. Ph.D. thesis. University of Wisconsin-Madison U.S.A., 1993. 

Saleki-Gerhardt A. Role of water in the solid state properties of crystalline and amorphous form of sugars. Doctor of Philosophy Thesis, University of Wisconsin-Madison 1993 104—108. 

Fig. III-22. The three librauonal modes of water in the solid state.

Like any rule, this one has exceptions. For instance, fi for some ions in an aqueous solution is negative and sometimes—as in the case of water—in the solid state is greater than in the liquid state. This is exactly the opposite from what the rule would lead us to expect... 

AHf= Hf - H j l is the difference between partial molar enthalpy of solvent (water) in gel and pure liquid solvent (water) in surrounding Contrast this with the equation for water in the solid state (iee) ... 

The product is isolated from the reaction mixture by sublimation or steam distillation. [Mn2(CO)io] is a yellow crystalline compound, which is soluble in organic solvents and in [Ni(CO)4], but is insoluble in water. In the solid state, in air, [Mn2(CO)io] is stable for a long time, but in solutions it oxidizes with carbon monoxide evolution. The halogens easily oxidize [Mn2(CO)io], breaking its Mn —Mn bond and forming the halides [MnX(CO)5] (Table 2.24). 

If you were to take some ice (water in the solid state) from a freezer, place it in a flask, and then apply heat steadily, five things would happen ... 

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