V O L U M E 2 6 , N O . 6, J U N E 1 9 5 4
1097
1,2,5-TRINITROh'APHTHALENEI1
1.2.5-Trinitronaphthalene(II)is the form normally obtained on rfwystallization from either solution or fusion. These crystals stion- an optic axial angle, 2E, of ( - ) 65" with little or no dispersion. 1,3,8-TRIIVITRONAPHTHALENE
Excellent crystals of 1,3,8-trinitronaphthaleneare obtained from nitromethane, chloroform, ethyl alcohol, and acrtic acid. It is insoluble in water.
Optic Axial Plane. 010. Acute Bisectrix. a: A c = 30" in acute 4. FUSIOXDATA. l13,8-trinitronaphthalenesublimes belolv the melting point, t o give a few small equant monoclinic crystals lying usually on t,he clinopinacoid (010). The melting point is 218-210" with little, if any, decomposition. Crystallization occurs with little supercooling and although rapid at, first, the rate of crystallization is essentially zero a t room temperature. The patterns of shrinkage cracks and gas bubbles are characteristic (Figure 3). Conoscopic observations may show an optic axis at the edge of the field. -4thymol mixed fusion shows a variable acute profile angle; all refractive indices are greater than that of the thymol melt.
CRYSTAL AfORPHOLOGY
Crystal System. Monoclinic. Form and Habit,. Stubby prisms from nitroniethane showing the prism (110), baPal pinacoid ( O O l } , and usually the orthopinacoid [ 100). Interfacial A4ngleso(Polar). 110 A l i 0 = 128". Beta Angle. 125 . OPTICAL PROPERTIES
6
Refractive indices (5893 -\.: 25' '2.). ct 1.i.27 i 0.005; y = 1.84 2 0.01. Optic ;\sin1 .ingle? (5893 .\.; 23" C,). 21' DiFpewIoii. r > 2'.
=
1.602
0.002:
I
=
=
ACKNOWLEDGMENT
The work described was performed under- contract _between Cornel1 University and the Office of Scientific Research and Development during World War 11. rllfred T. Blomquist w : tech~ nical representative of OSRD Srrtion B-2-A supervising ~ i i o g r r s s of tliis v o r k . COSTXIBPTIOXS of crystallographic d a t a for tliis section should he Eent t o X-alter c'. McCrone, Analytical Section, .4rmour Research Foiinilation of Illin(iis In-titiite of Technology. ('hicago IO, Ill.
( - j 8s".
SCIENTIFIC C O M M U N I C A T I O N
Sealed-Tu be Combustion for Determination of Carbon, Hydrogen, and Nitrogen compounds can be burned in a sealed quartz tube in 0 pure oxygen together with a bit of metallic copper as shown 1 water, carbon dioxide, and nitrogen from the sample RGASlC
in Figure ; are the only gaseous compounds formed. 4 n y nitrogen oxidecopper oxide compounds formed ( 2 ) are decomposed as the exwss of oxygen diffuses into the copper. The capillaries are filled as described for the filling of Carius tubes ( 1 ) . The gases can be used for isotopic analysis in a n i a ~ spectioms eter or counter or they can be determined in the apparatus shown in Figure 2: After the apparatus has been completely evacuated and leveling bulb G lowered so that the mercury level is situated below C, the sample tube, placed in tube C as shown, is broken by turning glass fork D. G is raised until the mercury level is situated in the graduated tube, A , and gas volume anti mercury pressure (10 t o 30 mm.) are read. G is raised, stopcock b' is opened, and the gas volume is read a t atmospheric presmrty. Potassium hydroxide is drawn in through E and the gas volume is read again. T h e third reading gives the nitrogen, the carbon dioxide plus nitrogen, and the first water plus c.:ii.l)oi~tlioxide plus nitrogen. =\ feiv analyses carried out with 0.1- t o 0.2-mg. ;winples gavcx
an accuracy somea hat less good than that of the Pregl methods on the 5-mg. scale. It is, however, expected that this will be changed after a thorough investigation of the method. LITERATURE CITED
(1) Kirsten, IT., ASAL. CHEM..25, i 4 (1953). ( 2 ) Kirsten, W., Mikrochemie, 40, 121 (1952).
Itistitute of Medical Chemistry University of Uppsala Uppsala, Sv,wlen RECEIVED for review December 28,
'fP
A
0
5 b c
0
-
d
C b c
0
Figure 1.
Quartz Tube
Capillary with sample Capillary after addition of copper and application of constrictions C. Capillary sealed off n. Sample e . Metallic copper b Constriction d Point where capillarl- is sealed ob Tubes used in first experiments had a total length. when sealed off. of 120 m m . and a n inner diameter of 8 mm.
1853.
Accepted March 19, 1954.
cA. E.
L-
-
WOLFGANG KIRSTEN
-4.
E.
Figure 2.
Apparatus
Measuring tube Ground joint lubricated with silicone grease and tightly fixed. with strong springs c. Side tube for capillary with sainple D . Glass fork for holding and breaking capillary E . Stovcock of n,eaFiirine tube F . Sto'prock of coliipa~leon tube G . Lewling bulb H . Point where tub?* A and L widen K . Rubber stopper rriiiented into ground joint a i t h Kronigp glass crment. Inner bore lubricated with silicone grease i.. Comparison tube M . Expansion room for combustion gases A-. Glass collar for catching mercury drops Ho. hIercury I n the apparatus used for the first analyses t h e volume of t h e upper m ~ a s u r i n grapillary was 0 2 nil. and the total volume of the graduated part was 25 nil. T h e volume of room .If was a b o u t 150 ml.
