(free of other barium salts); no transfer of the sample from its preparation tube to the apparatus is necessary if the sample has been collected or prepared in a standard taper centrifuge tube (The preparative or collecting test tube becomes test tube A ) ; test tube G can be removed and placed in position A for the preparation of a uniformly mixed sample or for conversion of the obtained barium carbonate to carbon dioxide for other uses; and by use of preweighed centrifuge tubes gravimetric assay of the resulting barium carbonate is possible. The results in Table I were obtained with this equipment. Easily oxidizable and refractory materials were utilized
and results with or without ca,talyst and -with and without recycling are reported. ACKNOWLEDGMENT
The author is indebted to Samuel Gurin for his kind encouragement and advice. This work was carried out with the technical assistance of Herbert D. Straws.
(2) Phares, E. F., Long, M. V., J . Am. Chem. SOC.77, 2556 (1955). (3) Pregl, Fritz, Grant, Julius, 'Q:,antitative Organic Microanalysis, 4th ed., p. 62, Blakiston, Philadelphia, 1946. (4) Rabinowitz, J. L., Sall, Theodore,
Bierly, J. N Jr., Oleksyshyn, Olha. Arch. Bihchem. and Biovhus. ." 63, 437 (1956).
Van Slyke, Donald, Folch, Jordi, J . Biol. Chem. 136,509 (1940).
Van Slyke, Donald, Plazin, John, Weisiger, J. R., Zbid., 191, 299 (1951). (7) Van Slyke, Donald, Steele, Robert, Plazin, John, Ibid., 192, 769 (1951).
LITERATURE CITED
(1) Calvin, Melvin, Heidelberger, Charles,
Reid, J. C., Tolbert, B. M., Yankwich, P. E., "Isotopic Carbon," pp. 74, 79, Wiley, New York, 1949.
RECEIVED for review September 15, 1955 Accepted January 2 1957. All radioactive materials were obtAned on allocation froni the U.S. Atomic Energy Commission.
159. Aluminum Trifluoride, AIF, EUGENE
STARITZKY and L. 6. ASPREY
The University of California, Los Alamos Scientific Laboratory, Los Alamos, N. M.
ALUMINUM fluoride was prepared by
reaction of 99.99% pure aluminum metal with aqueous hydrofluoric acid. The compound was oven-dried a t 110" C., and then sublimed under vacuum. The structure of aluminum fluoride was determined by Ketelaar (1). The space group is R32 Dl with 2(A1F3)
-
~~~~~
~~
per unit cell. The cell dimensions determined by Ketelaar are, after converting from k X to Angstrom units, = 5.039 =k 0.005 A., a = 58'31'. MORPHOLOGY System and Class. Trigonal, trapeaohedral. ChsTAL
~
Powder X-Ray Diffraction Pattern of Aluminum Trifluoride hkl 110 211 210 222 200 220 201 321 21 1 332 3 10 112 320 422 202 432 433 212 411.330 30i 43 1 442 420 222
d, A.,
d, A . , Obsd.a
3.519 2.514 2.118 2.074 2.018 1,760 1.599 1.587 1.561 1.462 1.432 1.422 1,354 1,257 1.232 1.206 1,195 1.1781 1.1730 1.1626 1.1197 1.0750 1.0591 1,0514
3.52 2.512 2.119 2.074 2.019 1.759 1.600 1,587 1.560 1 460 1.431 1.422 1.355 1.257 1.233 1.207 1.195 1,1794
Calcd.
1.1741
1.1631 1.1202 1 ,0700 1.0593 1.0511
Ib 100 2 19 2 1 24 2 14 7
1 1 2 1 1 3 1 1
