CRYSTALLOGRAPHIC DATA
77. 3,4,5-Tricarbethoxypyrazole Contributed b J O N A T H A N PARSONS, Henry Ford Hospital, Detroit, Mich., and WALTER C. k C R O N E , Armour Research Foundstion of Illinois Institute of Technology, Chicago 16, 111. Principal Lines
NH'
I/II
10.28 8.12 7.50 6.53 5.96 5.71 5.20 4.87 4.73
2
1 10 6 3 2
d 4.51 4.21 4.08 3.97 3.84 3.66
7
3.58
3
3.44 3.31
6
l/lr 1 5
1
7 9 6
d
1/11
d
I/l#
d
l/I>
3.20 3.10 2.Y8 2.89 2.84 2.73 2.65 2.60 2.47
5 3 4 4 2 3 1 3
1
2.41 2.36 2.29 2.25 2.20 2.17 2.13 2.09 2.05
1 5 1 1 I 2 1 4 3
1.99 1.92 1.88
2 3
OPTICAL PROPERTIES Refractive Indices (5892 A.; 25" C.). 8 = 1.556 0.002. y = 1.582 =t0.002.
*
Structural Formula for 3,4,5-Tricarbethoxypyrazole
a =
1.85
1.80 1.70 1.65 1.58 1.49
I
2 3
1 2 1
2
1.485 =t0.003.
f
~,~,s-TRICARBETHOXYPYKAZOLE is very soluble in most organic solvent-.g., ethyl alcohol, benzene, and amyl aoehteand is slightly soluble in water, carbon tetraohloride, and acetone. It can he reorystdlhed from benzyl alcohol on a microscope slide (Figure 1). Large well-formed crystals can be obtained from bemyl alcohol solution by touching a drop containing the good crystals with B corner of filter paper to remove excesa solution and then teasing the best crystals away from the drop with a needle. Sliding the crystals with the needle across the slide wipes away the excess solution and precludes recrystallisation of smdl crystals on the well-formed crystals. CRYSTAL MORPHOLOGY CrySt,al System. Monoclinic. Form and Habit. Rods and tablets elonsated parallel to b showing the orthopinitcoid. I100 I ; ortho$Tome, I101 1; and clinodome, {Olll. Axiallatio. a:b:c = 1.417:1:1.310, Interfacirtl Angles(P_lar). 101 A 101 = 94"32'. 011 A 071 = 104" 48'. 101 A 100 = 136"48'. Beta Angle. 97" 35'. X-RAYDIFFRACTION DATA Space Group. P21 - C?. Cell Dimensions. a = 10.38 A,; b = 7.33A.; e = 9.60 A Formula Weishts per . Cell. 2 (1.996 raloulrtted from x-ray data). Formula Weight. 284.14. Density. 1.300 (displi~cemmt); 1304 (x-ray)
Figure 1. Typical Cry-stals of 3,4,5-Tricarhethoxypyrazole from Benzyl Alcohol on Miemscope Slide
d
Figure 3. Orthographic Projection of Typical Crystals of 3,4,5-Triearbethox.ypyrazole
Optic Axial Angles (5893 A.; 25' C.). 2V = (-)60" (rald a t e d from a,B, and y). 2E = 103". Dispersion. r > v, strong. Optical Axial Plene. 010. Acute Rinectrin. a A a. = 28' in obtuse 8. Molecular Refraction (R) (5893A.;25'C.). = 1.540. R (cralcd.) = 66.7; R (ohsd.) = 68.6. FUSIONDATA. 3,4,&Tricarhethoxyp azole melts without suhrmation or decomposition a t 92-93" C. The melt supercools to a v i s cous liquid and remainins liquid indefinitely. On rewarming. crystallization may oCcur; however, even seeding at 80" t o 85" C. results only in slow growth of rods(Figure2)withavariety of pmfile angles. All refraxtive indices observed are higher than that of the melt. Some crystals show an optic axis interference figure [ Z V = (-)60"; 1 > v, strong].
*&
Figure 2. Crystals from Melt C-sed
Niools
Conmmem~oasof arystauaeraphio dats for this section should be sent to Walter C. McCrone, Analrtical Seotion. Armour Research Foondation of ILlinois Inatitute ofTeohnolam, Chicago 16. 111
O o o e e d Nifole
241
