ANALYTICAL CHEMISTRY
552
Table 11. Absorption SpectrumQ Ordinary Vibration Direction Wave length, mp Description 440 Strong, wide 444
Weak, medium
469 471 477 479 482 484 487
Weak, narrow Weak, narrow Medium, wide Weak narrow Weak: narrow Weak, narrow Weak, narrow
496 512 520 522
a
Band
Extraordinary Vibration Direction Wave length, mp Description 440 Strong, medium Weak, narrow 441 448 452 469 471 478 480
h l e diu m ,,m ediu in Weak wide AIedidm, narrow Weak, narrow hledium medium Weak, n h u m
485 487 493 496 510 519 520 525 533
Strong, narrow Rlediuni, narrow Strong, medium Weak, medium Weak, wide Strong, medium Weak, narrow Medium, inediuni hledium, medium
Ordinary Vibration DirectionWave length, mp Description 535 Strong, medium 538 Strong, narrow 540 Strong narrow 542 Tt'eak, 'narrow 545 Medium, narrow 581 582 588
Extraordinary Vibration Direction Wave length, I ~ P Description 536 Strong, medium 538 Medium, narrow 540 Medium, narrow 544 548
551
Weak, narrow Strong, narfow hledium, wide
583 588 59 1 596 Medium, wide 595-602 600 Medium, wide} Strong, mediuin 607 Weak narrow 605 Weak, narrow 609 Stron;, medium 609 Medium, wide 613 Strong, medium 613 Weak, narrow Strong, medium 017 617 630 63 1 639 maxima in millimicrons, I.elative intensities, nd relative widths 0'bands as viewed wi.th Zeiss prism micro: ;pectiroiiieter eyr
LITERATURE CITED (1) Goldschmidt, V. N., Ulrich, F., Barth, T., S k r i f f e r Sorskc vsenskaps.~kad, osl0,I, ,~~at,-l\~atzLrv, ~ 1 1925, . xo,5 , 5-24, ( 2 ) I a n d e l l i , A,, Garz. china. {tal. 7 7 , 312-18 (1947). (3) Paulinp. L.. 2. K r i s t . 69, 415-21 (1929). (4) Strukturber. 1, pp. 242-4; 745, Akadeinische Verlagsgesellschaft, Leipzig, 1913-1928.
Strong, narrow Weak, narrow Medium, narrow Medium, medium Strong, mediuin Medium, narrow Medium Medium, medium Weak, medium Weak, medium Weak, mediurn Weak, narrow Weak narrow Weak: narrow tce.
(51 Swanson. H. E.. Fumt. R. IC.. Uarinic. G. AI.. Natl. Bur. Standurds Circ. 539, IV, 26 (1955). (6) Ttryckoff, R. W.G., "Crystal Structures," vel. 1, chap. V. P. 1. T a b l e pp. 3, 5, I n t e r s c i e n c e , New York, 1951. (7) Zachariasen, W.H., Z. p h y s i k . C h e w 123, 134-50 (1926). \\-ORK
done under the auspices of the Atomic Energy Coinmission.
112. Samarium Sesqsioxide, Sm,O,, Form B R. M.D O U G L A S S and EUGENE STARITZKY, The University of California, Los Alamos Scientific Laboratory, Los Alamos, N. M. of samarium sesquioxide form B were preA pared by crystals Irving R. Tannenbaum of this laboratory by fusing NHEDRAL
samarium sesquioxide in an oxyacetyleneflame (3000" to 3500" C). Form B has been recognized as one of the three polymorphic modifications of the rare-earth sesquioxides by Goldschmidt., Ulrich, and Barth ( I ) , who described it as pseudotrigonal, orthorhombic or monoclinic. No other crystallographic data on this form have been published. CRYST.4L bf ORPHOLOGY
The preparation examined consisted of coarse-grained nggregates of anhedral crystals.
X-RAYDIFFRACTION DAT~ Diffraction Symbol. 2/mC-/-, embracing space groups C2/m (&), C2 (C;), and Cm ((2). Cell Dimensions (from calibrated Weissenberg and precession photographs). uo = 14.177 f 0.01 A.: bo = 3.G33 f 0.01 A . ; co = 8.847 f 0.01 A.: B = 99.96 & 0.03"; n:b:c = 3.90:1:2.44; cell volume 448.8 A3 ' Formula Weights per Cell. 6. Formula Weight. 348.86. Density. 7.74 grams per cc. (calcu$ted; w i g h t of unit atomic weight 1.6602 X gram); i.68 (mean of densities of two small fused beads measured with Bernian balance).
OPTICALPROPERTIES Refractive Indices (5893 A.). IZS = 2.070 f 0.005, n 1 - = 2.093 f 0.005, nz = 2.095 f 0.005; geometric mean 2.086. Molecular refraction 23.8 cc. (using calculated density). Optic Orientation. Z = b. Optic Axial Angle (5893 A,). 2Vx = 291/20. Color. Yellowish tan. Absorption Spectrum (band maxima in millimicrons and relative intensities as viewed with Zeiss prism microspectrometric eyepiece). 468 (strong, wide), 472 (weak, wide), 482 (strong, narrow), 496 (very weak, narrow), 5GD (weak, narrow).
Partial Powder X-Rag Diffraction Pattern" hkl 111 401 402 003 31_0 203 112 600 5 1z 602 510 601 318 313
d , A., Calcd. 3.212 3.063 2,988 2.905 2,864 2.863 2.796 2.327 2.220 1 2.218 i 2.214 J 2.157 1.939 1.817 1.778 1 1 771 1.764 1.719
}
1
I
:;A \ 021
1
801
205 403
7 12
GO?
}
1.080
d , A., Obsd. b 3.185 3.040 2,980 2.890 2.843 2.780 2.315
2.208
IlIl
c
3 .3 10 4 5 4
