Triaid Döbereiner

Faoi 1829, i stair an tábla pheiriadaigh, luath iarracht ab ea triaid Döbereiner na dúile a shórtáil in ord loighciúil éigin de réir a n-airíonna fisiciúla. Sa bhliain 1817, thuairiscigh litir faoi bharúlacha Johann Wolfgang Döbereiner ar na miotail chré-alcaileacha; is é sin, go raibh airíonna ag an strointiam a bhí idirmheánach dóibh siúd a bhí ag cailciam agus bairiam.  From pp. 332–333:  "In der Gegend von Jena (bei Dornburg) … Schwerspaths seyn möchte." (In the area of Jena (near Dornburg) it is known that celestine has been discovered in large quantities.  This gave Mr. Döbereiner cause to inquire rigorously into the stoichiometric value of strontium oxide by a great series of experiments.  It turned out that it [i.e., the molar weight of strontium oxide] – if that of hydrogen is expressed by 1 or that of oxygen is expressed by the number 7.5 – is equal to 50.  This number is, however, precisely the arithmetic mean of that which denotes the stoichiometric value of calcium oxide (= 27.55) and of that which denotes the stoichiometric value of barium oxide (= 72.5) ; namely (27.5 + 72.5) / 2 = 50.  For a moment, Mr. Döbereiner found himself thereby caused to doubt the independent existence of strontium; however, this withstood both his analytical and synthetic experiments.  Even more noteworthy is the circumstance that the specific weight of strontium sulfide is likewise the arithmetic mean of that of pure (water-free) calcium sulfide and that [i.e., the sulfide] of barium, namely (2.9 + 4.40) / 2 = 3.65 ; which must cause [one] to believe even more that celestine might be a mixture of equal stoichiometric amounts of anhydrite [i.e., anhydrous calcium sulfate] and barite.)   Faoi 1829, bhí grúpaí eile de thrí dhúil (mar sin "triaid") aimsithe ag Döbereiner a raibh baint chéanna ag a n-airíonna fisiciúla leo. For an English translation of this article, see: Johann Wolfgang Döbereiner: "An Attempt to Group Elementary Substances according to Their Analogies" (Lemoyne College (Syracuse, New York, USA)) Thug sé faoi deara freisin gur lean roinnt airíonna inchainníochtaithe de dhúile (m.sh. meáchan adamhach agus dlús) treocht trína ndéanfaí luach na dúile lárnaí sa triad a thuar go díreach nó beagnach trí mheán uimhríochtúil luachanna don mhaoin sin den dá dhúil eile a thógáil.

+Mais adamhach tuartha vs mais adamhach iarbhír d'adamh lárnach i ngach triadAinm an triaidDúile agus maiseanna adamhachaDúil 1MaisDúil 2Meán of 1 and 3Mais iarbhírDúil 3Mais Dúile a chruthaíonn miotail alcaileLitiam6.94Sóidiam23.0222.99Potaisiam39.10 Dúile a chruthaíonn miotal chré-alcaileachaCailciam40.1Strointiam88.787.6Bairiam 137.3 Dúile a chruthaíonn salannClóirín35.470Bróimín80.47078.383Iaidín126.470 Dúile a chruthaíonn aigéadSulfar 32.239Seiléiniam80.74179.263Teallúiriam129.243  Triad iarainnIarann 55.8Cóbalt 57.2558.9Nicil58.7

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