THE PRINCIPLES OF CHEMISTRY

By D. MENDELÉEFF TRANSLATED FROM THE RUSSIAN (SIXTH EDITION) BY GEORGE KAMENSKY, A.R.S.M. OF THE IMPERIAL MINT, ST PETERSBURG: MEMBER OF THE RUSSIAN PHYSICO-CHEMICAL SOCIETY EDITED BY T. A. LAWSON, B.Sc. Ph.D. EXAMINER IN COAL-TAR PRODUCTS TO THE CITY AND GUILDS OF LONDON INSTITUTE FELLOW OF THE INSTITUTE OF CHEMISTRY IN TWO VOLUMES VOLUME II. LONGMANS, GREEN, AND CO 39 PATERNOSTER ROW, LONDON NEW YORK AND BOMBAY 1897 All rights reserved

Table III.

The periodic dependence of the composition of the simplest compounds and properties of the simple bodies upon the atomic weights of the elements.

Molecular composition of the higher hydrogen and metallo-organic compounds Atomic weights of the elements Composition of the saline compounds, X=Cl Peroxides Lower hydrogen compounds Simple bodies

Sp. gr. Sp. vol. Melting point

Br, (NO₃), ½O, ½(SO₄), OH, (OM)=Z, where M=K

½Ca, ⅓Al, &c.

E=CH₃, C₂H₅, &c. Form RX RX₂ RX₃ RX₄ RX₅ RX₆ RX₇ RX₈

Oxides R₂O RO R₂O₃ RO₂ R₂O₅ RO₃ R₂O₇ RO₄

[1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] [12] [13] [14] [15] [16] [17] [18] [19]

HH H 1,005 (mean) HX or H₂O H₂O₂ — _*0·05 20 -250°?

Li 7·02 (Stas) LiX — — 0·59 11·9 180°

Be 9·1 (Nilson Pettersson) — BX₂ — BeH 1·64 5·5 900°?

BE₃ — — B 11·0 (Ramsay Ashton) — — BX₃ — — 2·5 4·4 1,300°?

CH₄ C₂H₆ C₂H₄ C₂H₂ C 12·0 (Roscoe) — CO — COZ₂ C₂O_5* — _*1·9 6·3 2,600°?

NH₃ N₂H₄ — N 14·04 (Stas) N₂O NO NOZ NO₂ NO₂Z N₂O_6* N₃H _*0·6 23 -203°

OH₂ — O 16 (conventional) — OX₂ O₃ — _*0·9 18 -230°?

— FH F 19·0 (Christiansen) FZ — — — ?1·0 19 ?

NaE Na 23·04 (Stas) NaX NaO Na₂H 0·98 23·5 96°

MgE₂ — Mg 24·3 (Burton) — MgX₂ — MgH 1·74 14 500°

AlE₃ — — Al 27·1 (Mallet) — — AlX₃ — — 2·6 11 600°

SiH₄ Si₂E₆ — — Si 28·4 (Thorpe Young) — — — SiOZ₂ — — 2·3 12 1,300°?

PH₃ P₂H₄ — P 31·0 (v. d. Plaats) — — PX₃ — POZ₃ — P₂H 2·2 14 44°

SH₂ — S 32·06 (Stas) — SX₂ — SOZ₂ — SO₂Z₂ S₂O₇ — 2·07 15 114°

ClH Cl 35·45 (Stas) ClZ — ClOZ — ClO₂Z — ClO₃Z — — _*1·3 27 -75°

K 39·15 (Stas) KX KO₂ K₂H 0·87 45 58°

Ca 40·0 (Dumas) — CaX₂ CaO₂ CaH 1·56 26 800°

Sc 44·0 (Nilson) — — ScX₃ — — ?2·5 ?18 1,200°?

Ti 48·1 (Thorpe) — TiX₂ TiX₃ TiX₄ TiO₃ — 3·6 13 2,500°?

V 51·2 (Roscoe) — VO VOX — VOZ₃ — — — 5·5 9 3,000°?

Cr 52·1 (Rawson) — CrX₂ CrX₃ CrO₂ — CrO₂Z₂ Cr₂O₇ — 6·7 7·7 2,000°?

Mn 55·1 (Marignac) — MnX₂ MnX₃ MnO₂ — MnO₂Z₂ MnO₃Z — — 7·5 7·3 1,500°

Fe 56·0 (Dumas) — FeX₂ FeX₃ — — FeO₂Z₂ — Fe_nH_* 7·8 7·2 1,450°

Co 58·9 (Zimmermann) — CoX₂ CoX₃ CoO₂ — — 8·6 6·8 1,400°

Ni 59·4 (Winkler) — NiX₂ NiX₃ — Ni_nH 8·7 6·8 1,350°

Cu 63·6 (Richards) CuX CuX₂ Cu₂O_5* CuH 8·8 7·2 1,054°

ZnE₂ — Zn 65·3 (Marignac) — ZnX₂ ZnO₂ — 7·1 9·2 418°

GaE₃ — — Ga 69·9 (Boisbaudran) — — GaX₃ — — 5·96 11·7 30°

GeE₄ — — — Ge 72·3 (Winkler) — GaX₂ — GaX₄ — — 5·47 13·2 900°

AsH₃ — — As 75·0 (Dumas) — AsS AsX₃ AsS₂ AsO₂Z — As₄H_* 5·65 13·3 500°

SeH₂ — Se 79·0[A] (Pettersson) — — — SeOZ₂ — SeO₂Z₂ — — 4·8 16 217°

BrH Br 79·95 (Stas) BrZ — BrOZ — BrO₂Z — BrO₃Z — — 3·1 26 -7°

Rb 85·5 (Godeffroy) RbX RbO Rb₂H_* 1·5 57 39°

Sr 87·6 (Dumas) — SrX₂ SrO₂ SrH 2·5 35 600°?

Y 89 (Clève) — — YX₃ — — _*3·4 _*26 1,000°?

Zr 90·6 (Bailey) — — — ZrX₄ — Zr_4nH_* 4·1 2·2 1,500°?

Nb 94 (Marignac) — — NbX₃ — NbO₂Z — Nb_nH_* 7·1 13 1,800°?

Mo 96·1 (Maas) — — MoX₃ MoX₄ — MoO₂Z₂ Mo₂O₇ — 8·6 11 2,200°?

Unknown metal (eka-manganese, Em = 99). EmO₃Z — — — — —

Ru 101·7 (Joly) — RuX₂ RuX₃ RuX₄ — RuO₂Z₂ — RuO₄ — Ru_nH_* 12·2 8·4 2,000°?

Rh 102·7 (Seubert) — RhX₂ RhX₃ RhX₄ — RhO₂Z₂ — Rh_nH_* 12·1 8·6 1,900°?

Pd 106·4 (Keller Smith) PdX PdX₂ — PdX₄ — Pd₂H 11·4 8·3 1,500°

Ag 107·92 (Stas) AgX AgO — 10·5 10·3 950°

CdE₂ — Cd 112·1 (Lorimer Smith) — CdX₂ CdO₂ — 8·6 13 320°

InE₃ — — In 113·6 (Winkler) — InX₂ InX₃ — — 7·4 14 176°

SnE₄ — — — Sn 119·1 (Classen) — SnX₂ — SnX₄ SnO₃ — 7·2 16 232°

SbH₃ — — Sb 120·4 (Schneider) — — SbX₃ — SbO₂Z — — 6·7 18 432°

TeH₂ — Te 125·1 (Brauner) — — — TeOZ₂ — — 6·4 20 455°

IH I 126·85 (Stas) IZ — IZ₃ — IO₂Z — IO₃Z — — 4·9 26 114°

Cs 132·7 (Godeffroy) CsX — Cs₂H_* 2·37 56 27°

Ba 137·4 (Richards) — BaX₂ BaO₂ BaH 3·76 36 ?

La 138·2 (Brauner) — — LaX₃ — — 6·1 23 ?

Ce 140·2 (Brauner) — — CeX₃ CeX₄ — — 6·6 21 700°?

Little known Di = 142.1 and Yb = 173.2, and over 15 unknown elements.

Ta 182·7 (Marignac) — — — — TaO₂Z — Ta_nH_* 10·4 18 ?

W 184·0 (Waddel) — — — WX₄ — WO₂Z₂ W₂O₇ — 19·1 9·6 2,600°

Unknown element.

Os 191·6 (Seubert) — — OsX₃ OsX₄ — OsO₂Z₂ — OsO₄ — — 22·5 8·5 2,700°?

Ir 193·3 (Joly) — — IrX₃ IrX₄ — IrO₂Z₂ — Ir_nH_* 22·4 8·6 2,000°

Pt 196·0 (Dittmar McArthur) — PtX₂ — PtX₄ — Pt_nH_* 21·4 9·2 1,775°

Au 197·5 (Dittmar McArthur) AuX — AuX₃ — — 19·3 10 1,045°

HgE₂ — Hg 200·5 (Erdmann Mar.) HgX HgX₂ — — 13·6 15 -39°

TlE₃ — — Tl 204·1 (Crookes) TlX — TlX₃ — — 11·8 17 294°

PbE₄ — — — Pb 206·90 (Stas) — PbX₂ — PbOZ₂ — — 11·3 18 328°

BiE₃ — — Bi 208·9 (Classen) — — BiX₃ — BiO₂ — — 9·8 21 269°

Five unknown elements.

Th 232·4 (Krüss Nilson) — — — ThX₄ — — 11·1 21 ?

Unknown element.

U 239·3 (Zimmermann) — — — UO₂ — UO₂X₂ — UO₄ — — 18·7 13 2,400°?

Columns 1, 2, 3, and 4 give the molecular composition of the hydrogen and metallo-organic compounds, exhibiting the most characteristic forms assumed by the elements. The first column contains only those which correspond to the form RX₄, the second column those of the form RX₃, the third of the form RX₂, and the fourth of the form RX, so that the periodicity stands out clearly (see Column 16).

Column 5 contains the symbols of all the more or less well-known elements, placed according to the order of the magnitude of their atomic weights.

Column 6 contains the atomic weights of the elements according to the most trustworthy determinations. The names of the investigators are given in parenthesis. The atomic weight of oxygen, taken as 16, forms the basis upon which these atomic weights were calculated. Some of these have been recalculated by me on the basis of Stas's most trustworthy data (see Chapter XXIV. and the numbers given by Stas in the table, where they are taken according to van der Plaats and Thomsen's calculations).

Columns 7–14 contain the composition of the saline compounds of the elements, placed according to their forms, RX, RX₂ to RX₈ (in the 14^th column). If the element R has a metallic character like H, Li, Be, &c., then X represents Cl, NO₃, ½ SO₄, &c., haloid radicles, or (OH) if a perfect hydrate is formed (alkali, aqueous base), or ½ O, ½ S, &c. when an anhydrous oxide, sulphide, &c. is formed. For instance, NaCl, Mg(NO₃)₂, Al₂(SO₄)₃, correspond to NaX, MgX₂, and AlX₃; so also Na(OH), Mg(OH)₂, Al(OH)₃, Na₂O, MgO, Al₂O₃, &c. But if the element, like C or N, be of a metalloid or acid character, X must be regarded as (OH) in the formation of hydrates; (OM) in the formation of salts, where M is the equivalent of a metal, ½ O in the formation of an anhydride, and Cl in the formation of a chloranhydride; and in this case (i.e. in the acid compounds) Z is put in the place of X; for example, the formulæ COZ₂, NO₂Z, MNO₂Z, FeO₂Z₂, and IZ₃ correspond to CO(NaO)₂ = Na₂CO₃, COCl₂, CO₂, NO₂(NaO) = NaNO₃, NO₂Cl, NO₂(OH) = HNO₃; MnO₃(OK) = KMnO₄, ICl, &c.

The 15th column gives the compositions of the peroxides of the elements, taking them as anhydrous. An asterisk (*) is attached to those of which the composition has not been well established, and a dash (—) shows that for a given element no peroxides have yet been obtained. The peroxides contain more oxygen than the higher saline oxides of the same elements, are powerfully oxidising, and easily give peroxide of hydrogen. This latter circumstance necessitates their being referred to the type of peroxide of hydrogen, if bases and acids are referred to the type of water (see Chapter XV., Note 7 and 11 bis).

The 16th column gives the composition of the lower hydrogen compounds like N₃H and Na₂H. They may often be regarded as alloys of hydrogen, which is frequently disengaged by them at a comparatively moderate temperature. They differ greatly in their nature from the hydrogen compounds given in columns 1–4 (see Note 12).

Column 17 gives the specific gravity of the elements in a solid and a liquid state. An asterisk (*) is placed by those which can either only be assumed from analogy (for example, the sp. gr. of fluorine and hydrogen, which have not been obtained in a liquid state), or which vary very rapidly with a variation of temperature and pressure (like oxygen and nitrogen), or physical state (for instance, carbon in passing from the state of charcoal to graphite and diamond). But as the sp. gr. in general varies with the temperature, mechanical condition, &c., the figures given, although chosen from the most trustworthy sources, can only be regarded as approximate, and not as absolutely true. They clearly show a certain periodicity; for instance, the sp. gr. diminishes from Al on both sides (Al, Mg, Na, with decreasing atomic weight; and Al, Si, P, S, Cl, with increasing atomic weight, it also diminishes on both sides from Cu, Ru, and Os.)

The same remarks refer to the figures in the 18th column, which gives the so-called atomic volumes of the simple bodies, or the quotient of their atomic weight and specific gravity. For Na, K, Rb, and Cs the atomic volume is greatest among the neighbouring elements. For Ni, Pd, and Os it is least, and this indicates the periodicity of this property of the simple bodies.

The last (19th) column gives the melting points of the simple bodies. Here also a periodicity is seen, i.e. a maximum and minimum value between which there are intermediate values, as we see, for instance, in the series Cl, K, Ca, Sc, and Ti, or in the series Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, and Ge.