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Salts of H,CrO, with those of

H.Mno, and H,Te0 Cr,03 with Al2O3, M110, and Feug Mn,03 with AlO3, Cr,0, and

Fe,, RMn0, with R. Cro
and R,Teon, 'RMno, with
KCIO
Fe,0, and derivatives with Al,0g,

Cr,Öz. Mn,O, and derivatives,
some Fe salts with those of Ni,
Co, and Cu
Ni with Co compounds, some Ni

compounds with those of Fe
(ferrous salts)
Co with Ni compounds, some Co
compounds with those of Fe
(ferrous salts)
most Cu compounds with those of

Ni and Co, some with Fe (ser.
rous) compounds, Cu with Ag
compounds of type R20
Zn compounds with those of Mg

and Mn
Ga alum with other alums

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As compounds with those of Sb
and Bi, organic compounds of
As with those of N, P, and Sb,
arsenates with phosphates and
vanadates
Se with S compounds
Bromides with analogous com-
pounds of Cl and I
Rb compounds with those of other
alkali metals

BROMINE

SeHą, Seo

directly
BrH, Br(CH3), Br,Cd, directly
Br,B, Br, Sn, Br,U, &c.

indirectly: doubtful
[from comparison of specific heats
of some compounds with those
of other alkali metals]

RUBIDIUM

none

STRONTIUM

nonc

indirectly : doubtful
(comparison of specific heats of

compounds of Sr, Ca, and Ba]

Sr compounds with those of Ca and Ba, and with some Pb salts

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sp. heats of a few compounds de. Yt compounds with those of other termined

earth metals directly [? too low]

Zr0, with Tio, Tho,, SnO, and

SiŐ, Nb with Ta compounds, Nb fluorides and oxyfluorides with Mo

do. do. directly [? too high)

Mo with W compounds, some salts of H M00, with those of H.CrO,, Mo with Nb fluorides and oxyHuorides

MOLYBDENUM MOCI,

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26'2

mate

55

27.5

559

27 95

55 9 (see p. 56)

586

293

20 Chromium chloride, silver

chromate, potassium dichro21 Manganese chloride, mangan.

ous-manganic oxide, manganous oxalate, silver per

manganate, &c. 22 Synthesis of ferric oxide,

reduction of ferric oxide, analysis of ferrous and ferric

chlorides 23 Nickel chloride, nickelous ox

ide, strychnine-nickelcyanide,

brucine-nickel cyanide, &c. 44 Ammonium . cobalt cyanide,

phenyl-ammonium cobalt cy: anide, strychnine and bru.

cine-cobalt cyanides 25 Reduction of copper oxide,

electrolysis of copper sul

phate, &c. 25 Synthesis of zinc oxide, analy.

sis of potassium-zinc chloride 27 Oxidation of the metal, analy.

sis of gallium-ammonia alum 28 Arsenic bromide, do. chloride,

do, oxide

59

29'5

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317

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32'3

69

23

69 (see p. 56)

74'9

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Rb. From analogies between Rb(and its salts) and the metals of the al. kalis, the formulæ RbCI, Rb,O, &c. are most probably correct : if so, the atomic weight of Rb is to be taken as equal to its combining weight. Sr. The atomic weight of strontium

must be taken as 4365 X 2 = 87'3 if the formula of its salts are to become analogous to those of the Ba and Ca salts. Yt. Atomic weight probably = 29*87 x3 = 89'6 because of analogy of Yt salts with those of earth metals.

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3132

zirconium fluoride
35 Niobium chloride, potassium-

niobium oxyfluoride
36 Molybdenum dichloride, tetra-

chloride and pentachloride

95.8

19*16

M. C.

6

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none

none

com

RUTHENIUM

directly

most Ru compounds with those of

Rh, Pd, Ir, Pt and Os PALLADIUM

directly

most Pd compounds with those of

Ru, Rh, Ir, Pt and Os SILVER none directly

some Ag compounds with those of Na and other alkali metals, Ag with Cu compounds of type R,O, a few Ag and Au com

pounds CADMIUM CABr

directly

some Cd compounds with those of

Be and Zn INDIUM InCl,

directly

some In compounds with those of

Cd and Be
TIN
SnClz, SnC,, Sn,Cla directly

SnO, with TiO2, Zr0, and Tho, ANTIMONY ShH3, SbCl3, SbF3, directly

Sb compounds with those of As Sb(CH3)2

and Bi IODINE IH, ICI, I(CH2', 1.P, directly

Iodides with analogous 1,Hg, 13P, 1,As, I.Si,

none

pounds of Cland Br* 1.AZ, &c. TELLURIUM Tella

directly

most Te compounds with those

of S and Se CÆSIUM

indirectly: doubtful

Cs compounds with those of other (comparison of specific heats of metals of alkalis

compounds with those of other

alkali metals] BARIUM none indirectly: doubtful

Ba compounds with those of Ca (comparison of specific heats of and Sr

compounds of Ca, Sr, and Ba) LANTHANUM none

directly CERIUM

directly

most La compounds with those of DIDYMIUM

Ce, Di, Er and Yt, some comnone directly

pounds of these metals with Ca ERBIUM

sp. heats of a few compounds

compounds

determined YTTERBIUM

sp, heats of a few compounds (? a few Yb compounds with those determined

of other earth metals) TANTALUM TaCl,

Ta with Nb compounds TUNGSTEN WOCIĄ, WCI,, WCIA directly

W with Mo compounds, some salts of H.WO, with those of

H.Cro, and H, Tel. IRIDIUM

directly OSMIUM OSO,

directly

Os, Ir and Pt compounds with

those of Ru, Rh and Pd PLATINUM none

directly

none

none

none

none

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Er. This metal belongs to the earth group, hence the atomic weight is taken as 55:33 X 3 = 166. Yb. For similar reasons to those which apply in cases of Sc, Yt and Er, the atomic weight of Viterbium is supposed to be 3 times its combining weight (= 173).

182

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54 Potassium - tantalum fluoride,

ammonium-tantalum fluoride 53 Reduction of tungstic oxide,

306

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analysis of tungsten hexclor

ide 54 Potassium iridium chloride

57 Osmium tetroxide

48.13 48 25 48.575

58 Potassium-platinum chloride

(s. The number given is calculated from 2 determinations of vapour density of Os(), by Deville and Debray, other experimenters have found numbers for atomic weight of this metal varying from 195 to 197.

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Notes to Table of Atomic Weights.
A. As the method based on isomorphism of compounds is chiefly used as a
means of verifying values assigned to atomic weights by other methods, no num-
bers are given in column iv., but merely an indication of the various compounds
which have been compared crystallographically, and on which, arguments for or
against a given value for the atomic weights in column v. have been, or may
be, based.

B. This column (vi.) is not to be regarded as containing anything like a
complete summary of the processes employed for determining the combining
numbers of the elements; only the more important processes are indicated ;-
references are given to the original papers.

A complete account of all researches on this subject will be found in A Ricalculation of the Alomic Weights, by F. W. Clarke [Part v. of the Constants of Nature published by the Smithsonian Institution), and also in Die Atomgewichte der Elemente, by L. Meyer and K. Seubert [Leipzig, 1883].

C. When the atomic weight given in column V. section (2) is a multiple of the combining number in column vii., no number being given in section (1) of column V., it is to be inferred that, besides the argument drawn from the value of the specific heat of the element in question, there are other chemical reasons for adopting the special multiple which appears in v. (2): these reasons may be broadly described as based on analogies between salts of the given element and salts of other elements, the atomic weights of which have been established by the two leading physical methods.

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