Formulae addition compounds

To seat ch for available starting materials, similarity searches, substructure searches, and some classical retrieval methods such as full structure searches, name searches, empirical formula searches, etc., have been integrated into the system. All searches can be applied to a number of catalogs of available fine chemicals (c.g, Fluka 154]. In addition, compound libraries such as in-housc catalogs can easily be integrated. 

Bismuth trichloride shows considerable tendency to form addition compounds. Reaction with ammonia yields the colodess, easily volatili2ed bismuth trichloride triammine [66172-89-2] BiCl ANH, as well as the red, thermally unstable bismuth trichloride hemiammine [66172-90-5] 2BiCl2 NH. Compounds of formula BiCl NO, BiCl 2N02, and BiCl NOCl may be isolated these are stable in dry air but are decomposed by moisture. Bismuth... 

Addition compounds are represented by the formulae of the individual constituent species, with suitable multipliers that define the appropriate molecular ratios of the constituent species, and separated by centre dots. In general, the first symbols determine the order of citation. 

This last example shows how the formula of a compound considered as an addition compound is converted to a name. The molecular proportions are shown as the appropriate ratio (here, 1/12) in parentheses after the names, which are separated by a long dash. 

On the other hand, the suggestion has been made that the polysulphides are analogous in structure to the periodides and are to be represented as additive compounds of hydrogen sulphide with sulphur of the general formula H2S. Sn.2 In such a case, the additional sulphur atoms... 

Analogous with the tetrachloride and tetrabromide, additive compounds are formed by the tetra-iodide with the alkali iodides. The telluri-iodides,9 of the general formula XaTeIe, are black, crystalline substances, which, like the tellurichlorides and telluribromides, generally crystallise in the regular system when anhydrous. They are decomposed... 

Addition compounds. In the formulae of addition compounds, the component mole cules are cited in order of increasing number, if they occur in equal numbers, they are cited in alphabetical order of the first symbols. Addition compounds containing boron compounds or water are exceptional, in that the water or boron compound is died last. If both are present, the boron precedes water. 

Water of hydration, when so identified, and other components of clathrates and addition compounds are not added into the formulas of the constituent compound. Components of addition compounds (other than water of hydration) are entered at the formulas of both components. 

Figure 14.23 gives the (solid + liquid) phase diagram for (tetrachloromethane + 1,4-dimethylbenzene).19 The maximum in the (solid + liquid) equilibrium curve at X2 = 0.5 results from the formation of a solid addition compound with the formula CCl4-l,4-C6H4(CH3)2 that melts at the temperature corresponding... 

Figure 14.29 shows the (solid + liquid) phase diagram for (benzene + hexafluoro-benzene). A congruently melting solid molecular addition compound with the formula QFU-CeFe ) is evident in this system.26 The rounded top of the freezing curve (solid line) for the addition compound results from almost complete dissociation of the addition compound in the liquid mixture. In other words, benzene and hexafluorobenzene act as independent molecular species in the liquid state and combine together as the addition compound only in the solid state. 

The addition of one equivalent of a heteroatom nucleophile to carbonyl compounds was described in Section 9.1. However, if two or more equivalents of the heteroatom nucleophile are present, in many cases the initial addition products (formula A in Figure 9.12) react... 

Many other addition compounds have been reported by various workers. By mixing bromine with phosphorus trichloride, heating on the water-bath and then cooling to about -5° C. brown needle-shaped crystals have been obtained, the analysis of which leads to the formula PCl3Br8.3 By allowing this compound to stand with PC1S in a sealed tube for some days red crystals separated which had the composition PCl3Br4.4... 

The unsaturated character of these trialkyl esters was shown by the ease with which they were attacked by nitric acid, but still more clearly by the formation, with evolution of heat, of stable crystalline addition compounds when they were mixed with cuprous halides. Thus CuC1.P(OC2H5)3 was described as consisting of colourless crystals melting at 190° to 192° C. and soluble in organic solvents.4 This property they share with phosphine, alkylphosphines and phosphorus trihalides. The phosphoric esters were quite indifferent to cuprous halides. Nor were such addition compounds formed either by phosphorous acid itself or by the dialkyl esters, which may show that the latter compounds have the unsymmetrical formula. Phosphorous acid probably exists in both forms, but first as P(OH)3, i.e. when produced from PC13 and Ha0.5 This may be transformed into the unsym-metrieal form through an addition compound HC1.P(0H)3,4 and probably also exists in the form of complex molecules, such as... 

In the formula for an addition compound, use a centered dot, closed up on each side. (Although the IUPAC books show a space on each side, this spacing would wreak havoc with many typesetting systems.)... 

Molecular addition compounds are indexed under the formulae of their components (except that entries are not made for a few common components). Thus, the 1 1 addition compound of ethanol with sulflnylbis(methane) (dimethyl sulfoxide (DMSO)) appears at C2HgO (ethanol) and at C2H( OS (sulflnylbismethane) and not at C4H12O2S. 

Divide constituents into electropo tive and electronegative. This requires decisions concerning compound type. There are special rules for acids, polyatomic groups, binary compounds, chain compounds, intermetaliic compounds, coordination compounds, and addition compounds [q.v.]. Assemble foe formula. 

With hexamethylene tetramine, or urotropine, an addition compound of the following formula is obtained ... 

The manner in which chloroacetone reacts with other compounds is also interesting. With gaseous ammonia, for example, aminoacetone is formed, and with nascent hydrogen (from zinc and acetic acid) it is converted into acetone. Damp silver oxide oxidises it to glycollic, formic and acetic acids. On combination with sodium bisulphite, acicular crystals are formed, probably of an additive compound of the formula ... 

With Iodine Trichloride. On adding a carbon tetrachloride solution of dichloroethyl sulphide to a solution of iodine trichloride also in carbon tetrachloride, an addition compound of the following formula is immediately formed ... 

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