Formulae chain compounds

Hexane refers to the straight-chain hydrocarbon, C H branched hydrocarbons of the same formula are isohexanes. Hexanes include the branched compounds, 2-methylpentane, 3-methylpentane, 2,2-dimethylbutane, 2,3-dimethylbutane, and the straight-chain compound, / -hexane. Commercial hexane is a narrow-boiling mixture of these compounds with methylcyclopentane, cyclohexane, and benzene (qv) minor amounts of and hydrocarbons also may be present. Hydrocarbons in commercial hexane are found chiefly in straight-mn gasoline which is produced from cmde oil and natural gas Hquids (see Gasoline AND OTHER MOTOR fuels Gas,natural). Smaller volumes occur in certain petroleum refinery streams. 

Woker points out that the closing of a chain compound to form a ring compound does not affect the odour much, thus the aliphatic terpineol of W. H. Perkin, Jr., 2 3 di-methyl 5 hexenol 2 has a verj similar odour to a-terpineol, their respective formulae being —... 

Baker and Smith have isolated an alcohol of the formula C,oH,gO from the cajuput oil, distilled from the leaves of Melaleuca uncinata. The alcohol, which is probably an open-chain compound, forms snow-white crystals, melting at 72 5°, and having a specific rotation + Sfi fifi . 

Naphthenes (C Hj ) have the same formula as olefins, but their characteristics are significantly different. Unlike olefins that arc straight-chain compounds, naphthenes are paraffins that have been bent into a ring or a cyclic shape. Naphthenes, like paraffins, are saturated compounds. Examples of naphthenes are cyclopentane, cyclohexane, and methylcyclohexane (Figure 2-3). 

Arts. These compounds can each form isomers (having the same molecular formulas). C4H,0 can occur as a straight-chain compound and a branched-chain compound. C3H6 can occur with a double bond or in a ring. 

By very careful hydrogenation (with stannous chloride in ethereal hydrogen chloride) phenyl azide has been converted into the exceedingly sensitive phenyltriazene (Dimroth), which, as has been shown, can be reconverted into the former by dehydrogenation. As in the case of the aliphatic diazo-compounds, an open chain structural formula has lately also been assigned to hydrazoic acid and its esters, so that the changes just mentioned may be formulated as follows ... 

Normal" The designation given to a straight-chain compound that has isomers. The designation in tire molecular formula is an "n-" in front of the formula. 

The three types of compounds to be considered here are a homologous series of linear polysilanes with the general formula CH3[Si(CH3)2]BCH3, where n equals 2 through 12 a few branched-chain compounds and three cyclic polysilanes of the formula [(CH3)2Si] , n being 5, 6, and 7. 

Another type of extended array is also built up of octahedra, but with the sharing of opposite faces. Compounds in this class range from those containing only two or three fused octahedra to infinite chain compounds (Fig. 16-24), which have deceptively simple formulas such as MzMoeXg (X = S, Se, Te M = In, Tl, Na, K). 

The compound consists of macroanionic chains (empirical formula [ZrP20ioH3] ), separated by NH4 cations. The octahedral Zr atoms are bridged with PO4 and HPO4 groups via Zr-O-P-O-Zr linkages. Thus each ZrOe octahedron shares four PO4 tetrahedra with each of its neighbors on either corner. 

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. 

A-cyclic or Open Chain Compounds.—Such compounds, because their structure is that of a chain of carbon groups, the ends of which chain do not unite to form a ring, are known as open chain or a-cyclic compounds in distinction from closed chain or cyclic compounds which we shall meet with in the second part of our study. Their structure explains also the general formula for the series as given at the top of the table, viz., CnH2n+2- Each carbon atom excepting the two end... 

Such a formula as this agrees with the facts we have thus far given in regard to benzene, viz., that it is not an unsaturated open chain compound, nor is it an ali-cyclic compound like cyclo-hexane. It is, however, directly related to the latter. 

Similarly, the absorption of only one mole of hydrogen shows that cyclohexane contains only one carbon-carbon double bond yet its molecular formula is which in an open-chain compound would correspond to two carbon-carbon double bonds or one triple bond. Again, only a cyclic structure fits the facts. 

IR-4.4.3.2 Formal treatment as coordination compounds IR-4.4.3.3 Chain compounds IR-4.4.3.4 Generalized salt formulae IR-4.4.3.5 (Formal) addition compounds IR-4.4.4 Figand abbreviations IR-4.5 Isotopically modified compounds IR-4.5.1 General formalism IR-4.5.2 Isotopically substituted compounds IR-4.5.3 Isotopically labelled compounds IR-4.5.3.1 Types of labelling IR-4.5.3.2 Specihcally labelled compounds IR-4.5.3.3 Selectively labelled compounds IR-4.6 Optional modibers of formulae IR-4.6.1 Oxidation state IR-4.6.2 Formulae of radicals IR-4.6.3 Formulae of optically active compounds IR-4.6.4 Indication of excited states IR-4.6.5 Structural descriptors IR-4.7 References... 

For chain compounds containing three or more different elements, the sequence of atomic symbols should generally be in accord with the order in which the atoms are bound in the molecule or ion, rather than using alphabetical order or order based on electronegativity. However, if one wishes to view a compound formally as a coordination compound, e.g. in connection with a discussion of additive naming of the compound, one may use a coordination-compound type of formula, as in Example 1 below. 

While the bulk of the hydrocarbon content of crude oils is represented by the paraffins, naphthenes, and aromatics, small percentages of several other types of compounds are also present. Olefinic hydrocarbons, unsaturated chain compounds having a carbon-carbon double bond and a type formula CnH2n, also occur in natural petroleum but only to a very small extent since they are relatively unstable. They are mentioned here, however, since substantial amounts of these are formed by some refinery processes, in particular those involving cracking. 

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