VOL.
XXXIX.
No. 12.
DECEMBER] 1917.
THE JOURNAL OF THE
American Chemical Society with which has been incorporated the
American Chemical Journal (Found4 by Ira Remsen)
INTERNATIONAL COMMITTEE ON ATOMIC WEIGHTS. On account of the difficulties of correspondence between its members, due to the war, the International C,ommittee on Atomic Weights has decided to make no full report for 1918. Although a good number of new determinations have been published during the past year, none of them seems to demand any immediate change in the table for 1917. That table, therefore] may stand as official during the year 1918. F. W. CLARKE,Chairman. INTERNATIONAL ATOMICWEIGHTS, 1917. Symbol.
Aluminum.. ............A1 Antimony.. . . . . . . . . . . . .Sb Argon.. . . . . . . . . . . . . . . . .A Arsenic. . . . . . . . . . . . . . ..As Barium. . . . . . . . . . . . . . . . B a Bismuth. . . . . . . . . . . . . . .Bi Boron.. . . . . . . . . . . . . . . . .B Bromine. . . . . . . . . . . . . ..Br Cadmium.. . . . . . . . . . . . .Cd Caesium. . . . . . . . . . . . . ..Cs Calcium.. . . . . . . . . . . . . . .Ca Carbon.. . . . . . . . . . . . . . . C Cerium. . . . . . . . . . . . . . . . .Ce Chlorine. . . . . . . . . . . . . ..C1 Chromium.. . . . . . . . . . . . .Cr
Atomic weight
2711 120.2
39.88 74.96 137.37 208.0 I 1 .o
79.92 112.40 132.81 40.07 12 .oo5 140.25
35.46 52.0
Symbol.
Cobalt.. . . . . . . . . . . . . . . .Co Columbium.. ........... Cb Gopper.. . . . . . . . . . . . . . . . Cu Dysprosium. . . . . . . . . . . * DY Erbium.. . . . . . . . . . . . . . .Er Europium. . . . . . . . . . . . ..Eu Fluorine.. . . . . . . . . . . . . ..F Gadolinium.. . . . . . . . . . . .Gd Gallium.. . . . . . . . . . . . . . .Ga Germanium.. . . . . . . . . . ..Ge Glucinum. . . . . . . . . . . . . .G1 Gold.. . . . . . . . . . . . . . . . . .Au Helium. . . . . . . . . . . . . . . . H e Holmium.. ............ .Ho Hydrogen . . . . . . . . . . . . . .H
Atomic weight.
58.97 93.1 63.57 162.5 167.7 152. o 19.0 157.3 69.9 72.5 9.1 197.2 4.00 163.5 I .008
25 18
CHARLES
.
.
.
t BURDICK A N D JAMES H ELLIS
INTERNATIONAL ATOMIC WEIGHTS.I 9I 7 (continued). Symbol .
Indium . . . . . . . . . . . . . . . . .In Iodine. . . . . . . . . . . . . . . . .. I Iridium . . . . . . . . . . . . . . . . .Ir Iron .................... Fe Krypton . . . . . . . . . . . . . . . .Kr Lanthanum............. .La Lead ................... Pb Lithium ................. Li Lutecium ............... Lu Magnesium . . . . . . . . . . . . .Mg Manganese . . . . . . . . . . . . .Mn Mercury . . . . . . . . . . . . . . . .Hg Molybdenum . . . . . . . . . . . .Mo Neodymium .............Nd Neon . . . . . . . . . . . . . . . . . .Ne . Nickel .................. Ni Niton (radium emanation)Nt Nitrogen. . . . . . . . . . . . . . . . N Osmium . . . . . . . . . . . . . . ..Os Oxygen .................0 Pdladium ...............Pd Phosphorus .............P Platinum . . . . . . . . . . . . . . .Pt Potassium ..............K Praseodymium . . . . . . . . . .Pr Radium . . . . . . . . . . . . . . . Ra . Rhodium Rh
................
Atomic weight
.
Symbol
Rubidium . Rb Ruthenium . . . . . . . . . . . . .Ru Samarium . . . . . . . . . . . . . .Sa
114.8 126.92 193.1 55.84 82.92 139.0
Silicon . . . . . . . . . . . . . . . . .Si
.
207 20
6.94 I75 .0 24.32 54.93 200 .6 96.0 144.3 20.2
58.68 222.4
14.01 190.9 16.00
106.7 31.04 195.2 39 1 0 140.9 226.0 +
Tin .................... Sn Titanium . . . . .Ti Tungsten ............... W Uranium ................U Vanadium . . . . . . . . . . . . .V . Xenon .................. Xe Ytterbium(Ne0ytterbium)Yb Yttrium . . . . . . . . . . . . . . . Y .t Zinc ..................... Zn Zirconium...............Zr
.
,
.
Atomic weight
.
85.45 101.7 150.4 44.1 79.2 28.3 107.88 23.00 87.63 32.06 181.5 127.5 159.2 204.0 232.4 168.5 118.7 48.1 184.0 238.2 51.0
130.2 173.5 88.7 65 -37 90.6
102.9
[CONTRIBUTIONS FROM THE CHEMICAL LABORATORIES OF
TECHNOLOGY. N o . 3.1
THROOP COLLEGEOF
THE CRYSTAL STRUCTURE OF CHALCOPYRITE DETERMINED BY X-RAYS
.
BY CHARLBS L . BURDICK AND JAMES H . Received October 3. 1917
Introduction.
.
ELLIS .
This investigation of the atomic structure of crystals of chalcopyrite (CuFeSz) was undertaken. as no study of a complex sulfide by the method of X-rays had previously been carried out . Moreover. comparatively few crystals of the tetragonal system in which chalcopyrite crystallizes, have been examined. the only ones being certain oxides (rutile. anatase. cassiterite. zircon) of the formula MOz studied by Vegard' and by Williams.2 Yet the determination of the structure of crystals belonging to other than the isometric system is likely t o throw most light on the fundaPhil . Mag., 32, 65. 505 (1916) . * Proc. Roy . SOC. London. 93. 418 (1917).
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