V O L U M E 28, NO. 1 2 , D E C E M B E R 1 9 5 6
2023
.4xial Elements. a:b:c = 0.493:1:0.464 (derived from unit cell dimensions). Habit. Dipyramidal by equaldevelopment of (111)and ( 1171, usually with subordinate (010) and often with [ 110). No hemihedral development was noted.
X-RAYDIFFRACTION DATA Space Group. Fddd (Ci:).
Cell Dimensions. a. = 11.17 ZIZ 0.03 A . ; bo = 22.68 =E! 0.06 A , : co = 10.53 f 0.04 A. Formula Units per Cell. 8; volume per formula unit 333.5 .4.3 Formula T e i g h t . 478.24. Density. 2.38 grams per cc. (x-ray); 2.403 (flotation).
144. 145. 146. 147.
Yttrium Sesquioxide, Y,O, Dysprosium Sesquioxide, Dy,O; Erbium Sesqeioxide, Er,O, Ytterbium Sesquioxide, Yb,O,
E U G E N E STARITZKY, The University of California, Los Alamor Scientific Laboratory, Los Alamos. N. M.
Partial Powder X-Ray Diffraction Pattern d , A., Calcd. 7 26 5 67 5.38
hkl
5.01
4.78 3.98 3.90 3 83 3 63 3.47 3 31 3.18 3.17 3.13
d , A., Obsd." 7.23 5.64 5.36 4.98 4.76 3.97 3.88 3.82 3.61 3 46 3 30
2.984 2,835 2,792 2 , 778 2.711 2.694'l 2.6911 2,632 2.538
