Hydrated compounds

Iron(III) ammonium citrate [1185-57-5] is of indefinite stoichiometry. A brown hydrated compound [1332-98-5] of iron(III) ammonium citrate contains 16.5—18.5% iron, - 9% ammonia, and 65% citric acid. A green hydrated compound [1333-00-2] contains 14.5—16% iron, 1% ammonia, and 75% citric acid. Iron ammonium citrates are water soluble but are insoluble in alcohol. The compounds are used to fortify bread, milk, and other foods (see... 

Nitrates. Anhydrous zirconium tetranitrate [12372-57-5] Zr(N02)4, is prepared from zirconium tetrachloride and nitrogen pentoxide (201). The hydrated compounds are obtained from aqueous nitric acid (165) Zr0(N02)2 2H20 [20213-65-4] is most commonly used Zr(N02)4 5H20 [12372-57-5] can be produced from strong nitric acid. 

Removal of water from gases may be by physical or chemical means, and is commonly by adsorption on to a drying agent in a low-temperature trap. The effectiveness of drying agents depends on the vapour pressure of the hydrated compound - the lower the vapour pressure the less the remaining moisture in the gas. 

Anhydrous An anhydrous material does not contain any water molecules. Many substances occur naturally as hydrates, compounds that have a specific number of water molecules attached to them. This water can often be removed by heating and/or vacuum to give the anhydrous material. Anhydrous materials can absorb water from their surroundings and find use as dessicants. Examples include those packets of silica gel you find in some consumer goods, as well as dehumidifying sachets used in clothes closets. When an anhydrous material reacts with water, this could release a large amount of heat, possibly leading to a heat or pressure buildup that could result in an explosion. 

An amino-formaldehyde resin or acetone-formaldehyde resin has the capability to harden in alkaline media, in contact with a cement solution with a pH of 11 to 12. The presence of sintered CaO provides the required conditions for hardening of the methylol groups of the formaldehyde resin with Ca + ions and a further simultaneous reaction of the methylol groups that formed hydrate compounds, resulting in an improved dispersion and plastification of the solution. 

Fig.2 IR spectra of 4,4 -dipyridyl N,N -dioxide in the vo-h stretching region for the hydrated compound (black line, bottom) and the complex it gives with 1,4-DITFB (grey line, top). Hydration water disappears on complex formation...

Formaldehyde is usually described as a gas, but it also exists dissolved in water or other solvents. Because of very strong tendencies to hydrogen-bond, both formaldehyde and water combine avidly to make a hydrated compound called methylene glycol (Fig. 12.2). 

Hydrates are compounds that incorporate water molecules in their crystalline structures. The ratio of moles of water to one mole of the compound is a small whole number. For example, in the hydrated compound copper(ll) sulfate pentahydrate (CuS04,5H20), the ratio is 5 1. The ratio of moles of water to one mole of a hydrate can be determined experimentally by heating the hydrate to remove water. 

How can you determine the moles of water in a mole of a hydrated compound ... 

Heat a known mass of hydrated compound until the water is removed. 

Calculate the formula for a hydrate using the mass of the hydrated compound and the mass of the anhydrous compound. 

Water is a strong ligand toward the lanthanides. Consequently, most of the lanthanide compounds contain water when they are prepared from aqueous solutions or when hydrated salts are used as starting materials. Water in these compounds can be either coordinated or lattice held. Due to the preponderance of these hydrated compounds,... 

The elemental analysis of our synthetic octosyl acid A, was correct for a non-hydrated compound. Secondly, Its 400 MHz H-NMR spectrum showed no trace of any other Isomer. Danishefsky, and Hungate (8) had reported [alp +9.1 for their synthetic octosyl acid A in good agreement with our results. In the light of the spectroscopic and analytical data obtained, we contend that our sample of synthetic octosyl acid A is pure and that the constants we report are reliable. A NMR spectrum of synthetic octosyl acid A is shown in Figure 22. 

A hydrated compound, [Pd(NH3)2Cl2]H20, is obtained by treating an alcoholic suspension of the anhydrous body with concentrated aqueous ammonia and evaporating the mixture on a water-bath. The... 

Depending on conditions, frozen substances in comet nuclei can be crystalline ices, amorphous ices, and clathrate hydrates (compounds in which cages in the water-ice lattice can host guest molecules). Compositions of the ices and associated organic materials in comets have been determined from both telescopic and spacecraft observations. Spectral line measurements of gases in a comet s coma allow the identification of molecules and radicals. An inherent difficulty in spectral measurements is that volatiles in the coma are commonly broken... 

In the hydrated compounds (included in Table 24) the water molecules are almost certainly not bonded to the actinide(IV) ion, with the possible exception of the complexes formulated as MIrrh(N03)5-xH20 (MI = Na or K) and K3H3Th(N03)io-xH20, the nature of which is uncertain. 

Hydrated compounds of the type U02(H2L) xH20 have been reported for 1,2-diamino-propane-Af.NjA jAf -tetraacetic acid (x unspecified), tram diaminocyclohexane-N,N,N, N -tetraacetic acid (x = 0 or 3 (U02)2L-xH20, with x = 0 or 6 also known), 2,2 -diaminodiethyl ether-A, A,N, N -tetraacetic acid (x = 3), and 2,2 -diaminodiethyl sulfide-N,N,N, N -tetra-acetic acid (x = 0 or 4) the hydrates are predpitated from aqueous media, but in the last instance a mixture of ethanol and acetone was added to induce precipitation. The analogous di(2-aminoethoxy)ethane-/V, N,N, N -tetraacetic acid (H4L) forms the compounds... 

H2S04H20, is produced, accompanied by higher hydrated compounds defined by the formula H2S04 xH20. Likewise nitric acid is capable of forming hydrates. Thus in the nitrating mixture an equilibrium corresponding to the eqn. (1) is postulated ... 

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