CRYSTALLOGRAPHIC D A T A
78. Succinic Acid I (Butanedioic Acid) Contributed by W. C. MCCRONE and RALPH Illinois Institute of Technology, Chicago 16,111.
HITES, JR., Armour Research Foundation of
S
UCCINIC acid crystallizes readily on a microscope slide from water or benzyl slcohol. It is almost insoluble in ether, benzene, Canada balsam, moclor, and the Cargille refractive index media. A second modification of succinio acid stable abovo 137" C. has been reported (S). This modification should not be confused with the recrystallization of the stable form which occurs just after solidification of the melt (see fusion data).
Figure 2.
Crystals of Sueeinio Acid From tho melt
C
Figure 1.
C
Crystals of Suceinio acid Sul3limate
r'cx !209 Figure 3.
Optic Axial Plane. 010. Acute Bisectrix. a Extinction. Y A c = 45" in acute E. Molecular Refraction (R) (5893 A.,' 25" C.). = 1.530. R(calcd.) = 23.8. R(obsd.) = 23.4. FUSIONDATA. Succinic acid melts at 189' C . with sublimation. Twinned crystals lying on 010 are very common (Figure 1). The melt crystallizes spontaneously on cooling a few degrees below the melting point and usually shows extensive reerystdliaation for a few seconds (Figure 2). This phenomenon is very similar in appearance to a polymorphic transformation hut on reheating, the two areas show little further change and both melt at 189" C.
Principal Lines d 5.51 4.88 4.69 4.44 4.05 3.80 3.49 3.41 3.33 3.27 2.84 2.76 2.63 2.55 2.44 2.41 2.37
I/Ii 3 1
2 8 5 1 5 10 1 1
8 4 3 4 2 2 8
d 2.34 2.29 2.26 2.22 2.14 2.11 2.06 1.930 1.913 1.891 1.867 1.802 1.742 1.727 1.709 1.669
1.643
1/11 8
1 1
4 7 2 3 4 4 1
3 5 2 1
2 2 1
d
1.608 1.585 1.564 1.535 1.512 1.500 1.486 1.444 1.428 1.378 1.346 1.315 1.222 1.215 1.150 1.132
Orthographic Projection of Typical Crystal of Succinic Acid
l/I, 4 4 5 1
ACKNOWLEDGMENT
3 3 2
Joan French determined the x-ray powder diffraction data
3 1
LITERATURE CITED (1) Groth, P., "Chemisehe Xristnllographie." Vol. 111. p. 263, Leipeig, Engelmann, 1910. (2) Morrison. J. D.. and Robertson, J. M.. J . C h a . SOC.(London), 1949, 980. (3) Winchell, A. N., "Optioal Properties of Organio Compounds," P. 29, Madison, University of Wisconsin Press. 1943. (4) Yardley, K., P m .Roy. Soc. (London), 105A. 451 (1924).
1
1 1
1 1
4 3
OFTICALPROPERTIES
Refractive Indices (5893 A,; 25" C.). a = 1.450 =t 0,002, = 1.534 i 0.002, y = 1.610 =t 0.002. ODtic Axial Andes (5893 A,: 25"'C.). 2V = 1-)82" (calculatea from a,8, &d i);87" (8)
C o ~ ~ n r ~ r n r oof l r serystallogrwhic data for thia section should be 6ent to Walter C. MeCrone. Anslytiosl Section. Armour Research Foundation of Illinois Institute of Technology, Chioago 16. Ill.
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