{
    "system": "GoGuides Verified Text",
    "api_version": "verified-text-v1",
    "status": "ok",
    "response_type": "verified_text_record",
    "source_key": "britannica_1911",
    "source_title": "Encyclopaedia Britannica (1911)",
    "license_code": "public_domain",
    "attribution": null,
    "license_url": null,
    "chunk_id": "1911:ch2o:9ce6858ecda3",
    "title": "CH2--O",
    "section": null,
    "hash_alg": "sha256",
    "hash_sha256": "b35fe72fba4ab5b2605cb12a968dc0c245f4c725ee991408e13776c3f4226f19",
    "normalizer": {
        "name": "ggnorm",
        "version": "1.0"
    },
    "verified_text": "whereas honey-sugar corresponds to ch2oh.choh.choh.choh.choh.cho, each point representing a linking of the carbon atom to the next. this observation is closely related to the above-mentioned resistivity of the carbon-link, and corroborates it in a special case. as carbon tends to hold the atom attached to it, one may presume that this property expresses itself in a predominant way where the other element is carbon also, and so the linkage represented by --c--c-- is one of the most difficult to loosen. the conception of metamerism, or isomerism in restricted sense, has been of the highest value for the development of our notions concerning molecular structure, i.e. the conception as to the order in which the atoms composing a molecule are linked together. in this article we shall confine ourselves to the fatty compounds, from which the fundamental notions were first obtained; reference may be made to the article chemistry: _organic_, for the general structural relations of organic compounds, both fatty and aromatic. a general philosophical interest is attached to the phenomena of isomerism. by wilhelm ostwald especially, attempts have been made to substitute the notion of atoms and molecular structure by less hypothetical conceptions; these ideas may some day receive thorough confirmation, and when this occurs science will receive a striking impetus. the phenomenon of isomerism will probably supply the crucial test, at least for the chemist, and the question will be whether the ostwaldian conception, while substituting the daltonian hypothesis, will also explain isomerism. an early step accomplished by ostwald in this direction is to define ozone in its relation to oxygen, considering the former as differing from the latter by an excess of energy, measurable as heat of transformation, instead of defining the difference as diatomic molecules in oxygen, and triatomic in ozone. now, in this case, the first definition expresses much better the whole chemical behaviour of ozone, which is that of \"energetic\" oxygen, while the second only includes the fact of higher vapour-density; but in applying the first definition to organic compounds and calling isobutylene \"butylene with somewhat more energy\" hardly anything is indicated, and all the advantages of the atomic conception--the possibility of exactly predicting how many isomers a given formula includes and how you may get them--are lost. to kekule is due the credit of taking the decisive step in introducing the notion of tetravalent carbon in a clear way, i.e. in the property of carbon to combine with four different monatomic elements at once, whereas nitrogen can only hold three (or in some cases five), oxygen two (in some cases four), hydrogen one. this conception has rendered possible a clear idea of the linking or internal structure of the molecule, for example, in the most simple case, methane, ch4, is expressed by h | h--c--h | h it is by this conception that possible and impossible compounds are at once fixed. considering the hydrocarbons given by the general formula c_xh_y, the internal linkages of the carbon atoms need at least x - 1 bonds, using up 2(x - 1) valencies of the 4x to be accounted for, and thus leaving no more than 2(x + 1) for binding hydrogen: a compound c3h9 is therefore impossible, and indeed has never been met. the second prediction is the possibility of metamerism, and the number of metamers, in a given case among compounds, which are realizable. considering the predicted series of compounds c_nh_(2n + 2), which is the well-known homologous series of methane, the first member, the possible of isomerism lies in that of a different linking of the carbon atoms. this first presents itself when four are present, i.e. in the difference between c--c--c--c and c--c--c | . c with this compound c4h10, named butane, isomerism is actually observed, being limited to a pair, whereas the former members ethane, c2h6, and propane, c3h8, showed no isomerism. similarly, pentane, c5h12, and hexane, c6h14, may exist in three and five theoretically isomeric forms respectively; confirmation of this theory is supplied by the fact that all these compounds have been obtained, but no more. the third most valuable indication which molecular structure gives about these isomers is how to prepare them, for instance, that normal hexane, represented by",
    "source_url": "https://archive.org/details/EB1911WMF",
    "observed_at": "2026-02-08 18:43:09",
    "integrity": {
        "hash_check": "match",
        "hash_scope": "full_normalized_text",
        "computed_sha256": "b35fe72fba4ab5b2605cb12a968dc0c245f4c725ee991408e13776c3f4226f19"
    },
    "machine_use": {
        "read": true,
        "cite": true,
        "decision": "verified_public_domain_text"
    },
    "goguides_data_license": "https://www.goguides.com/data-license",
    "goguides_data_license_version": "2.0",
    "documentation": {
        "white_paper_url": "https://www.goguides.com/white-paper.php",
        "pdf_url": "https://www.goguides.com/whitepapers/goguides-ai-source-clearance-white-paper.pdf"
    }
}