A treatise on chemistry. Vol. II, Metals. Part II / by H.E. Roscoe & C. Schorlemmer ...

  • Roscoe, Henry E. (Henry Enfield), 1833-1915.
Date:
1880
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Licence: Public Domain Mark

Credit: A treatise on chemistry. Vol. II, Metals. Part II / by H.E. Roscoe & C. Schorlemmer ... Source: Wellcome Collection.

Provider: This material has been provided by University of Bristol Library. The original may be consulted at University of Bristol Library.

    531/576 (page 511)
    aud heptads. But the original idea of quantivalence (see vol. ii. part i., page 28) was deduced from the observation that different elements combine with 1, 2, 3, or 4 atoms of hydrogen to form volatile compounds, no compounds with 5, 6, or 7 atoms of hydrogen being known. In order to avoid confusion in this respect Lothar Meyer^ has introduced the term index of afinitij, by which he signiiies the quantivalence obtained from the con- sideration of the composition of the highest oxides. He has shown that these, as well as their hydroxides, may be represented by the general formula i-r,„XA.in0i-H,.X0v_4«. wheia (X) signifies the element in question, (v) the index of affinity, and (n) a small whole number. The compounds given on page 512 correspond, amongst others, to the above formula. Many of these formula are divisible by two, and the simple formulcB ordinarily in use are thus obtained. In a similar way the formulse of the chlorates, sulphites, selenites, nitrites, and phosphites may be represented by the general formula and the chlorites, liypophosphites, and hyposulphites by the formula IIo„X20v-+n_4, &c. The oxychlorides and chlorides, &c., may be represented in a similar way, and thus a classification may be introduced corresponding to that which has long been emploj^ed in organic chemistry. Up to the present time, however, such an arrange- ment has been necessarily incomplete in the case of inorganic compounds, and one of the m.ost important problems to the solution of which cliemists have to direct their attention is the discovery of the general law which governs the relation- ships observed in the natural classification of the elements, for this law will express the mode of the formation of all chemical compounds. ' Bcr. Dculsch. Chcm. Gcs. vi. 101.