1848
L. BROUSSARD
extended charge since the ions must reach the surface before specific adsorption is possible. We should also like to mention in passing that it is possible to give a more accurate account of the diffuse nature of the boundary between the extended charge and the bulk solution during the charging period. This has not been included here since the potential a t the surface would not be changed significantly.
Conclusions Large, nonequilibrium potentials should be produced by large, fast changes in the charge of an ideally polarizable electrode in a dilute solution. This phenomenon, which can be analyzed by neglecting diffusion, is associated with a charged region much thicker than the equilibrium diffuse charge layer. Such potentials should decay faster than can be observed in most experiments. Nonequilibrium potentials associated with the back-diffusion of salt into the space vacated by the extended charge should be smaller in magnitude but persist for longer times. Acknowledgment. The problem treated here was posed to the author by Fred C. Anson. This work was supported by the United States Atomic Energy Commission.
Nomenclature A B Ci
c
Di e
E &
F F L
Ni !l
Q R t ti
T T X
X 2/ zi E K, U
uz 7
0
Dimensionless parameter; see eq 6 Magnitude of electric field far from electrode, V/cm Concentration of species i, mol/cma Dimensionless average concentration of cations and anions Diffusion coefficient of species i, cmz/sec Dimensionless electric field Dimensionless electric field Electric field, V/cm Faraday's constant, C/equiv See eq 33. Disturbance distance, cm Flux of species i , mol/cm2 sec Dimensionless charge density Dimensionless charge density Universal gas constant, J/mol deg Time, sec Transference number of species i Absolute temperature, OK Dimensionless time of charging Distance from inner limit of diffuse layer, om Dimensionless distance Dimensionless distance Charge number of species i Dielectric constant, F/cm Conductivity of bulk solution, mho/cm Dimensionless surface charge density in diffuse layer Dimensionless surface charge density in extended oharge Dimensionless time Dimensionless potential a t X = 0
The Disproportionation of Wustite by L. Broussard Esso Research Laboratories, Humble 0.11 and Refining Company, Baton Rouge Refinery, Baton Rouge, Louisiana (Received May 1 6 , 1 9 6 8 )
Mossbauer spectrometry provided a new tool for studies of the mechanism of disproportionation of normally prepared nonstoichiometric wustite, FeO,. The conclusions of these studies are supported by chemical analyses and by X-ray diffraction data. Initially, FeO, disproportionates by forming FeaO4 using Fe3+ cations already present in the structure plus Fez+ and 02- ions necessary to form Fes0.i. Stoichiometric wustite, which we designate as FeOl.o, is also formed during this initial stage but no a-Fe is formed. Finally, when all Fe3+cations initially present have been used to make Fe304, FeOm begins to disproportionate forming a-Fe and additional Fea04according to the generally accepted formula: 4Fe0 + Fe -I-FeaOl.
Introduction The properties of nonstoichiometric wustite, FeO,, have been studied by many investigators.l-13 It is generally recognized that stoichiometric wustite is difficult to prepare. Katsuri, et aZ.,l3 report synthesizing FeOl.oooat high pressures above 36 kbars a t 770" by the reaction of FeOl.osz with metallic Fe. Fischer, et produced stoichiometric wustite by decomposing nonstoichiometric wustite containing 1.2% precipiThe Journal of Physical Chemistrv
tated iron. We will describe the formation of FeOl.0 by decomposing nonstoichiometric wustite containing (1) E. R . Jette and F. Foote, J . Chem. Phys., 1 , 29 (1933); Trans. Amer. Inst. M i n . Met. Engrs., 105, 276 (1933). (2) L. S. Darken and R. W. Gurry, J. Amer. Chem. SOC.,6 7 , 1398 (1945). (3) J. BBnard, Bull. SOC.Chim., 16, D109 (1949). (4) P. K. Foster and A. J. E. Welch, Trans. Faraday Soc., 5 2 , 1626 (1956). (5) W. A. Fischer. A. Hoffmann, and R. Shimada, Arch. Eisenhuttenw., 2 7 , 521 (1956).
THEDISPROPORTIONATION OF WUSTITE
1849
no metallic iron. I n this paper FeOl.o refers to compositions that are either stoichiometric or at least where x < 1.02. In addition, we will show how Mossbauer spectrometry serves as a new tool to describe the complete mechanism for the disproportionation of normally prepared wustite, FeO,. The consequence of the well-known deficiency of Fe in wustite (FeO,) is that some Fe3+ cations are required in this structure to provide electrical neutrality. Because of the presence of both Fe3+ and Fez+cations in these structures, Mossbauer spectrometry offers an attractive technique to characterize these materials. Unfortunately, the complete interpretation of the Mossbauer spectrum of FeO, is still a matter of some controversy.*J2 Work is in progress a t the Esso Research Laboratories to resolve this controversy and will be published later. However, for the purposes of this study on disproportionation it is sufficient to say that at room temperature FeO, gives a L'tw~-line" Mossbauer spectrum (actually one line is a doublet, see Table 111) and FeOl.o gives a "one-line" spectrum. These patterns are referred to later. The main purpose of this work is to describe the mechanism of the disproportionation of nonstoichiometric wustite. This explanation was developed independently by us from Mossbauer data and is supported by chemical analyses and by X-ray diffraction. As will be shown in the Discussion section of this paper, others had arrived a t this same explanation from other considerations.
Experimental Section Preparation of FeO, and Its Disproportionation. The starting material for all studies reported here was a naturally occurring hematite ore (a-FezOa). Typical analyses on this ore are given in Table I. From other studies carried out here we know that the majority (perhaps all) of the impurities (SiOz and AI2O3) are present as particles that are distinctly separate from the hematite particles. The ore was ground and screened through 60 on 200 mesh screens to provide good fluidizatJion in the reactor in which reduction and disproportionation took place. Reduction took place in a fluidized bed for 1 hr a t 732" in a gas stream consisting of 50% Hz-50% HzO a t atmospheric pressure. The samples were then treated with dry prepurified nitrogen for 15 min to remove hydrogen and water. The Table I: Typical Analyses on Hematite Ore Used in These Studies r
____ Wt
--Chemical----.
Total Fe Si02 AlzOa a
--
%.----M&wbauer----
65 2 0.8
Hematite
NOother Fe compounds were observable,
100"
temperature was then lowered quickly (60 to 90 sec) to 400" while continuing to fluidize the bed with prepurified nitrogen. The samples were kept fluidized with nitrogen at 400" for varying times to induce varying degrees of disproportionation. After disproportionation, the samples were quenched to room temperature by spraying cold water on the outside of the reactor. This quenching took place in 45 to 75 sec. Mossbauer Spectrometer. Our spectrometer is a conventional constant acceleration unit assembled a t this laboratory and patterned very closely to one a t the Bureau of Standards.14 We use a Nuclear Chicago ( I up-down" address scaler to accumulate 400 data points while scanning in one direction and repeating these 400 data points in reverse order while scanning in the other direction. A Reuter-Stokes proportional counter is used with an Austin Science Associates fast data accumulation system to gather data. The Mossbauer source was 67C0 in a platinum matrix. An annealed sample of a-Fe served as a calibration standard for the velocity scale and zero chemical shift is with respect to this iron absorber. All Mossbauer data were obtained with source and absorber at room temperature, Quantitative Analyses. The amount of FesO4 and of a-Fe in these samples was measured directly from the Mossbauer spectra. The absorption intensity of line 1 was used as a measure of the amount of a-Fe and the absorption intensity of line 10 was used as a measure of the amount of Fe304. No attempt was made to measure the amount of FeO, directly from Mossbauer spectra because of the changing nature of FeO, spectra. Quantitative data for Fea04 and for a-Fe were obtained by using calibration samples containing known amounts of FeO,, Fea04, and a-Fe. These calibration samples always contained the same amount of total Fe. I n getting Mossbauer spectra of these calibration samples and of all samples in this study 30 mg of sample were weighed out and carefully spread in collodion over a +in. diameter circle on a $-mil mylar support. In every case, sample thickness was adjusted to be as close as practical to a value of 23.G mg/cm2 of sample. Each sample was run long enough to accumulate roughly 250,000 counts in each of 400 channels. (6) A. Hoffmann, 2. Elektrochem., 6 3 , 207 (1959). (7) W. L.Roth, Acta Cryst., 1 3 , 140 (1960). (8) G. Shirane, D. E. Cox, and 8. L. Ruby, Phys. Rev., 1 2 5 , 1158 (1962). (9) T.Herai and J. Manenc, Mem. Scient. Rev. Met., 6 1 , 677 (1964). (IO) T. Herai, B. Thomas, and J. Manenc, ibid., 6 3 , 397 (1966). (11) R. L. Levin and J. B. Wagner, Jr., Tfans. Met. Soe. A I M E . 2 3 6 , 516 (1966). (12) H. Shecter, P. Hillman, and M. Ron, J . A p p l . Phys., 3 7 , 3043 (1966). (13) T. Katsuri, B. Iwasaki, 9. Kimura, and 9. Akimoto, J . Chem. Phys., 47, 4559 (1967). (14) J. J. Spijkerman. F. P. Ruegg, and J. R. Devoe, National Bureau of Standards Technical Notes 248, Aug 21, 1964, and 276. J a n 7, 1966, U. S. Government Printing Offlce, Washington, D. C.
Volume 75,Number E June 1969
1850
L. BROUSSARD
Table 11: Disproportionation of FeO, a t 400"
0 2 3 4 5 6
0 5 9 9 13 14 13 25 24 24 28 31 25 31
7 7.5 8 9 12 15 20 30
0 0 0 0 0 0 0 0 0 0 0 0 0 0
1.105" 1.09 1.08 1.08 1.07 1.07 1.07 1.03 1.04 1.04 1.02 1.01 1.03 1.01
...
...
0 14 17 16 25 25 28 30 26 29 30 31 30
0 0 0 0 0 0 0 0 0 0 0 0 0
... I00 86 83 84 75 75 73 70 74 71 70 69 71
4.2906 4.2958 4.3029 4.3048 4.3050 4.3096 4.3094 4.3199 4.3204 4.3144 4.3209 4.3228 4.3210 4.3226
0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0
59.5 57.5 59.1 59.1 66.8 59.1 58.7 57.5 58.4 58.6 58.2 57.6 60.9 58.9
14.0' 16.0 14.3 14.5 16.7 14.3 15.0 16.2' 15.4 15.2 15.4 16.0 12.7 13.8,
Av = 0.266(see Figure4)
Table 111: Effect of Disproportionation Time on Wustite Spectra" Reo,, mm/sec
Disproportionation time, min 0 2 3 4
5 6 7
7.5 8 9 12 15 20 30 45 BO 90 120 150 240 360 975
+0.47
I
fO.O1
29 23 19 17 16 10 9 2 0 4 0 0 0 0 0 0 0 0 0 0 0 0
I
+0.73 i O . 0 1
25 24 18 25 20 21 25 15 18 19 0 0 0 0 0 0 0 0 0 0 0 0
a-Fe, mm/sec
1
+0.85 &0.01
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 2 2 4 4 6
FeOl.0, mm/sec
1
+1.06 f O . 0 1
+1.28 i 0 . 0 1
0 3 12 8 13 21 19 37 36 33 69 69 63 68 65 57 52 34 29 10 9
45 37 30 35 32 24 25 12 12 16 0 0 0 0 0 0 0 0 0 0 0
0
0
Numbers in this table are relative areas of these absorption peaks based on computer-fitted curves, In each case these relative are&sare normalized so that total absorption due to all observed absorption lines = 100. The Journal
of
Phyeical Cheqistry
1851
THEDISPROPORTIONATION OF WUSTITE All Mossbauer data were analyzed also by a computer program, This program automatically scans the data, locates major absorption peaks, and fits the data with Lorentzian line shapes. From this program we get line positions, widths, and intensit,ies. In this case the areas, which are proportional to the product of intensity and width, were normalized so that the total area of all observed absorption lines was equal to 100. The computer data were especially useful in €allowing the changes taking place in the wustite structures. Chemical Analyses. All samples in this series of disproportionation runs were also submitted for chemical analyses for Fe", Fe2+ and Fea+. The bromine-methanol procedure of Kraft and Fischer16 was used for these analyses. X - R a y Diffraction. Conventional X-ray diffraction procedures were used to determine the amounts of crystalline FeO,, Fe304,and a-Fo in these samples and to determine the lattice constants of the various wustite samples. Accurate quantitative measurements were made by using CaFzas an internal standard and by calibrations with known mixtures of FeO,, Fe304, and a-Fe. Lattice constant determinations for FeO, were based on measurements of the position of the 220 line. I n general, these lines were sufficiently broad that their peak positions were located by a calculation of the centroid of the diffraction intensities.
3 .I
. *
Results Mossbauer Spectra. In this series of disproportion% tion studies a total of 22 samples were prepared with disproportionation times ranging from 0 to 975 min. Mossbauer spectra were obtained on each of these samples but due to space limitations only ten representative spectra are shown here. All the data (except computer data) are tabulated in Table 11. The computer data are given in Table 111. Figure 1 shows typical Mossbauer spectra of wustite samples that have disproportionated for various lengths of time. The following important features should be noted here. a-Fe is not formed in the initial stages of disproportionation-its first appearance occurs in the sample disproportionated for 60 min. The "two-line" Mossbauer pattern for wustite quickly changes to a "one-line" pattern in the initial stages of disproportionation. FeaO4 is formed in increasing amounts as the extent of disproportionation proceeds. Figure 2 shows that the amount of Fe304increases from the very beginning as the extent of disproportionation increases. This figure also shows that a-Fe was not observable by Mossbauer spectrometry until disproportionation was permitted to proceed for 60 min. The computer data applying specifically to the changes in wustite spectra are shown in Table IT1 and are plotted in Figure 3. These data show that FeOl.a
RELATIVE
VELOCITY
(mm/sec.)
Figure 1. Mossbauer spectra of FeO, after various times of disproportionation at 400': a, 0 min; b, 2 min; c, 4 min; d, 6 min; e, 8 min; f, 45 min; g, 60 min; h, 120 min; i, 240 min; and j, 360 min.
begins to form immediately-even after only 2 rnin of disproportionation. It is interesting to notice also that FeOl.,, is up to its maximum value in about 12 min; however, the amount of FeOl.o remains substantially constant up to 45-60 min, at which time it disproportionates rapidly. Chemical Analyses. The results of chemical analyses for Fe", Fez+, and Fea+ on all these samples are shown in Figure 4. These data also show that no metallic iron (Fe") was formed until a 60-min disproportionation time is reached. In addition, this figure shows that the amounts of Fez+and of Fea+remain constant until a 4560 rnin disproportionation time is reached. X - R a y Analyses. Quantitative data by X-ray diffraction for FeO,, FeaOl, and for a-Fe are shown in Table 11. The data for Fe304and for a-Fe agree so (16) G . Kraft and J. Fischer, 2. Anal. Chem., 197, 217 (1963).
Volume 7S,Number 6 June 1969
1852
L. BROUSSARD
40-
-
0 40 80 TIME (MiN.)
loo
200
500
Figure 2. Mossbauer analyses of disproportionated samples: 0,wt % FesOh; 0 , wt % a-Fe.
well with those from Mossbauer spectra that Figure 2 is substantially a plot of the X-ray data also. Lattice constant measurements for these various wustite samples are shown in Table I1 and are plotted against wustite composition in Figure 5. The wellknown increase in lattice constant as the composition of wustite approaches FeOl.,, is shown here compared with data reported by other observers.
in Table IV shows how the Fe cations rearrange themselves in the early stages. I n fact, “rearrangement” is more appropriate than “disproportionation” for this stage of the process shown in Table IV. By this mechanism, a-Fe will not be formed initially, but will be formed when FeOl.,, begins to disproportionate. From the data in Figure 4 the ratio of Fe3+ to Fezin the original wustite (FeO,) is found to be 0.265. This gives a value of 1.105 for z in FeO,. From these data we can calculate that according to the above mechanism of disproportionation, 33% Fe304 will be formed before a-Fe begins to form. Reference to Figure 2 shows that a-Fe begins to form at 45 to 60 min and at this time there is actually about 35% FeaOl in the disproportionated sample. Additional proof that this mechanism of disproportionation is correct can be seen from the data in Figure 4. The fact that the Fe2+content remains con80
I
I
I
I I Ill
I
I
I I I l l 1 1
I
1
I I I I I I
Discussion The material, FeO,, which was subjected to disproportionation was initially deficient in Fe. We know that FeO, contains both Fe3+ and Fe2+ cations. Because of these factors the usual disproportionation equation: 4Fe0 + Fe Fea04 cannot be used. Jnstead, it is more consistent with the data to consider disproportionation from the following point of view. For convenience, consider a unit cell of FeO, containing 32 oxygen anions instead of the crystallographic unit cell containing four oxygen anions. For z = 1.14 this unit cell contains 20 Fe2+ and 8 Fe3+ cations, a definciency of 4 Fe cations per unit cell. As disproportionation proceeds in the early stages, the Fe3+ cations (plus the required quantity of Fez+and 02-) are used first to form Fea04. This is indicated by the change from a “two-line” Mossbauer pattern to a “one-line” Mossbauer pattern for wustite. The scheme
+
0
40
TIME
(MIN.)
Figure 3. Effect of disproportionation time on wustite spectra: 0 , FeO,; 0,FeO1.o. The Journal of Physical Chemistry
TIME (MIN.)
Figure 4. Chemical analyses of disproportionated samples: 0 , wt % Fez+; A, wt % Fea+; 0,wt % Fe”.
stant for 45-60 min shows that the Fe3+cations already available in the FeO, structure are used first, along with the required numbers of Fez+ and Oz-, to form FeaO4. However, at ca. 45-60 min the wustite no longer has any Fe3+ cations. Therefore, Fez+ cations must be converted to Fea+cations to produce Fea04. At this stage the Fez+content in the sample begins to decrease, the Fe3+ content increases, and Fe” begins to form. The composition of the remaining FeO, at any time can be calculated by knowing the composition of the original FeO, and the amount of Fe304 that has been formed. Since the amount of FeaO4 is known to about &5% the value of z in FeO, is reliable to about f0.02. Our calculated values of wustite composition are plotted in Figure 5 to show the well-known fact that lattice constant increases as wustite composition approaches FeOl.o. These data show that considering
1853
THEDISPROPORTIONATION OF WUSTITE
h
Table IV : Rearrangement of Cations in Early Stages of Disproportionation Original wustite
4.82
(.
Magnetite
FeO1.14 a
32 0-2 Fez+]
..
8 FeS+
4,
-+
{
FeaOr
“Stoichiometric” wustite FeO1.o
16 4 Fez+] 0-2 f
{i:
8 Fe3+
a “Two-line” Mossbauer pattern representing FeO, containing both Fe*+ and FeZ+ cations. b “One-line” Mossbauer pattern representing FeOl.0 containing only or mostly Fez+ cations.
d
1.00
X IN FeO,
1.12
Figure 5. Effect of wustite composition on lattice constant (ao): (a) this work; (b) Levin and Wagner” (0)and Jette and Footel (0); (c) Foster and Welch;4 (d) BBnard;S (e) Katsura, et al.;13 and (f) Fischer, et aZ.6
the reliability of x as f0.02 in this new experimental approach our results are in reasonable agreement with those of Jette and Footel and of Levin and Wagner” within the range of composition covered by them. The slope of the curve given by Foster and Welch4 seems to be too low. BBnard’s3 data seem to reflect wustite compositions that were not as stochiometric as claimed. In the range near FeO1.o the results of Katsura, et ~ l . , ’ and ~ of Fischer, et suggest that our “stoichiometric” samples might still be slightly iron deficient. As refinements are made in this approach to this problem we expect the reliability of the data to increase so that more positive statements can be made in comparing our results with others. Since measurements of lattice constant are relatively easy to make with high accuracy, we feel that the improvements needed are in determining the composition of the wustite. Fischer, Hoffmann, and Shimadas developed a similar mechanism of disproportionation based on dilatometric, X-ray, and microscope studies. Their main conclusions were the following. 1. For Decomposition Temperatures below about 460”. Magnetite precipitates first, causing the remaining wustite to become enriched in Fe and thereby increasing its lattice parameter. Finally, the iron-enriched wustite disproportionates forming metallic iron and more magnetite. 2. For Decomposition Temperatures between 460 and 480”. Precipitation of metallic iron and magnetite occurs simultaneously.
3. For Decomposition Temperatures above 480”. Precipitation of metallic iron begins before the formation of magnetite. We have extended our studies in a limited way to cover the temperature range from 400 to 495’ in seven steps. In all cases magnetite precipitated first. Perhaps the difference between our results and those of Fischer, Hoffmann, and Shimada is due to the fact that our wustite samples contained no metallic iron initially whereas theirs contained above 1.2% iron. Herai and Manenee have employed microscopy, X-ray diffraction, and magnetic susceptibility to study the disproportionation of wustite. Their results indicate that disproportionation below 400” takes place in three stages: 1. pre-precipitation; 2. formation of magnetite with a corresponding enrichment in iron for the remaining wustite; and 3. formation of metallic iron and more magnetite. Stages 2 and 3 correspond to the two-step process we propose in this paper. Stage 1, pre-precipitation, is a step which we did not observe by X-ray diffraction, probably because our X-ray diffraction technique was not specifically directed to this problem. Herai and Manenc considered the possibility that the pre-precipitation stage supported Roth’s’ conclusion that FeO, contains clusters of defects having an atomic arrangement approximating that of Fes04. In a later study, Herai, Thomas, and Manendo interpreted their pre-precipitation stage as due to the formation of two phases of wustite: one rich in iron, the other rich in oxygen. Our Mossbauer data certainly show the presence of two types of wustite in the early stages (2-10 min) of disproportionation. We identify these as FeOl.o and FeO,. However, during this stage of decomposition we detect the formation of Fe304. This differs from Herai and Manenc’s pre-precipitation stage. The interpretation of our Mossbauer data directly in terms of Roth’s “clusters of defects” does not seem possible a t this time. This might be due to the fact that a completely satisfactory interpretation of the Mossbauer spectrum of FeO, has not yet been made. However, our observations that Fea04 begins to form at the very onset of wustite disproportionation, without the production of metallic iron, lends support to Volume Y$? Number 6 June 1960
1854
D. H. EARGLE, JR.
Roth's7 idea that FeO, contains regions having an atomic arrangement approximating that of Fes04. A point of interest to Mossbauer spectroscopists concerns the spectra we observe for FeO,. For the purposes of this paper we say that the Mossbauer pattern of FeO, consists of two absorption lines. This is based on its visual appearance. However, as shown in Table 111, the best computer fit shows that one of these lines is a doublet. This is consistent with observations made by Shirane, Cox, and Ruby.8
lattice; FeOl.o is produced in increasing amounts but does not disproportionate until all Fe8+ cations originally present are used to form Fed&; no a-Fe is formed. During the second step, true disproportionation takes place as FeOl.o begins to supply the Fe9+cations needed t o form Fea04and the Fe" to form a-Fe. I n this step the following takes place: FesOc continues to form in increasing amounts; a-Fe begins to form in increasing amounts; FeOl.o decreases in amount.
Summary From these results we conclude that wustite (FeO,) disproportionates in two steps. The first step is not a disproportionation but a rearrangement of Fe cations. During the first step the following takes place: FeaOl is produced in increasing amounts using preferentially Fea+ cations alrea,dy present in the FeO,
Acknowledgments. I take pleasure in acknowledging the helpful discussions I have had with Dr. D. P. Shoemaker, Dr. R. L. Collins, and Dr. M. E. Wadsworth. Sincere thanks are due also to Dr. W. J. Ristey for the X-ray data, Mr. R. C. Cox for computer analyses, Mr. W. H. Albritton for chemical analyses, and Mr. J. R. Wallace for preparing all samples and obtaining Mossbauer spectra.
Hyperfine Splittings in the Anion Radical of Thianthrene 5,5,10,10-Tetroxide and Molecules of Related Symmetry by D. H. Eargle, Jr. Department of Chemistry, University of Illinois, Chicago, Illinois
60680
(Received June 84, 1968)
Three sets of (natural abundance) hyperfine splittings have been detected for thianthrene 5,5,10,10-tetroxide of 4.74, 1.98, and 0.97 G and have been tentatively assigned to carbons 2, 1, and 4a, respectively. These splittings and other hyperfine splittings from molecules of Dzd symmetry are discussed.
In a recent study of thianthrene oxides the detection of 13C splittings in the epr spectra of the anion radical of thianthrene 5,5,10,10-tetroxide (I) were reported.' Recent measurements of the spectra (Table I) reflect some corrections and additional splittings obtained through considerably improved resolution. The observed splittings indicate the observation of three separate sets of lac splittings, designated by the subscripts 5,y, and z, arising from the natural abundance of 13C at the positions 1,2, or 4a.
1.2 x, Y = so2 11. x, Y = s 111. x, Y = 0 IV. X, Y = -C=CThe Journal of Physical Chemistry
thianthrene tetroxide thianthrene dibensodioxadiin
dibensocyolooctatetraene
Experimental Section Thianthrene tetroxide anion radical was produced by means of potassium metal reduction in 1,2-dimethoxyethane. The spectrometer used is a JEOLCO JES-3BSX (100-kc modulation). The instrument formerly used was not capable of the resolution found in the present study.
Results The y set of splittings possesses intensity ratios 1:4:6:4:1 as does the much more intense HB set. The 2 set has central peaks as close shoulders on the tail (1) D. H. Eargle, Jr., and E. T. Kaiser, Abstracts, 149th National Meeting of the American Chemical Society, Detroit, Mich., April 1965, p 455. (2) Numbering of these rings follows IUPAO Organic Nomenclature Rules B-2 and A-22.3. I would like to urge that other authors follow suit in order to avoid the prodigious proliferation of private preferences presently prevalent.
