construction of the electronic equipment. LITERATURE CITED
(1) , , Blake. G. G.. “Conductimetric Anal-
ysis at Radio-Frequency,” pp. 34-
42, Chemical Publishing Go., New York, 1952. (2) Crufts Electronics Staff, “Electronic Circuits and Tubes,” McGraw-Hill, New York, 1947. (3) Hall, J. L., Gibson, J. A., Phillips, H. 0.. Critchfield. F. E.. ANAL. CHEM.’26, 1539 (1954). ’
(4) Peech, AI., IND.ENG.CHEX, ANAL. ED.,13, 436 (1941). (5) Reilley, C. N., McCurdy, W. H., ANAL.CHEM.25, 86 (1953).
RECEIVEDfor review Mav . . 7.. 1956. Accepted January 28, 1957.
Selective Precipitation of Thorium Iodate from a Tartaric Acid-Hydrogen Peroxide Medium Application to Rapid Spectrophotometric Determination of Thorium in Silicate Rocks and in Ores F. S. GRIMALDI, LILLIE B. JENKINS, and MARY Geological Survey, Washington 25, D. C.
H.
FLETCHER
U. S.
)This paper presents a selective iodate separation of thorium from nitric acid medium containing d-tartaric acid and hydrogen peroxide. The catalytic decomposition of hydrogen peroxide is prevented b y the use of 8quinolinol. A few micrograms of thorium are separated sufficiently clean from 30 rng. of such oxides as cerium, zirconium, titanium, niobium, tantalum, scandium, or iron with one iodate precipitation to allow an accurate determination of thorium with the thoronmesotartaric acid spectrophotometric method. The method is successful for the determination of 0.001% or more of thorium dioxide in silicate rocks and for 0.01% or more in black sand, monazite, thorite, thorianite, eschynite, euxenite, and zircon.
T
HE precipitation of thorium iodate from nitric acid medium (4) is a generally reliable and widely used method for the separation of thorium. Lead, mercury, tin, niobium, tantalum, tungsten, cerium(IV), uranium(IV), zirconium, titanium, silver, and to a smaller extent scandium, bismuth, and iron(II1) also precipitate from this medium. A clean separation of thorium iodate is obtained from the rare earth elements by reprecipitation. A dense, less contaminated, and easily filterable precipitate is obtained from homogeneous solution (6). Tillu and Athavale (7) used oxalic acid to prevent the precipitation of 20 mg. each of titanium and bismuth and 40 mg. of zirconium. The procedure was not applied to the determination of small
848
ANALYTICAL CHEMISTRY
amounts of thorium. Kronstadt and Eberle (3) used mercury as a carrier for the precipitation of 20 y or more of thorium. The present investigation concerns the separation of thorium iodate from nitric acid medium containing hydrogen peroxide, d-tartaric acid, and S-quinolinol. Tartaric acid minimizes the coprecipitation of zirconium, tungsten, scandium, and bismuth. Hydrogen peroxide minimizes the precipitation of titanium, niobium, and tantalum; 8-quinolinol prevents the catalytic decomposition of hydrogen peroxide, which is especially serious in the presence of cerium. Although less than 10% of the iron added is precipitated, the mixed carrier of mercury and iron used is more effective than mercury alone for the precipitation of microgram amounts of thorium. This separation procedure combined with the recently developed (9) spectrophotometric determination of thorium with the thoron-mesotartaric acid system is applied successfully to the determination of 0.001% or more of thorium dioxide in silicate rocks and 0.01% or more in black sand, monazite, thorite, thorianite, eschynite, euxenite, and zircon. REAGENTS AND APPARATUS
All chemicals used are reagent grade. Ferric nitrate (carrier solution), 1 ml. equivalent to 2 mg. of Fe20B. Dissolve 0.875 gram of ferric nitrate hexahydrate in 100 ml. of (1 plus 99) nitric acid. Potassium hydroxide (precipitating solution), 50% by weight aqueous. Potassium hydroxide (wash solution). Dilute 2 ml. of 50’% potassium hydroxide solution to 500 ml. with water.
Ammonium nitrate (wash solution), 1% aqueous. 8-Quinolinol. Dissolve 0.5 gram of reagent in 100 ml. of (1 plus 99) nitric acid. Hydrogen peroxide solution, 3%. Dilute 10 ml. of 30% hydrogen peroxide to 100 ml. with mater. &Tartaric acid solution. Dissolve 600 grams of tartaric acid in sufficient water to make 1 liter of solution. Filter through a dry paper and do not mash. Potassium iodate solution, 6% aqueous. Filter through a dry paper and do not wash. Mercuric nitrate (carrier solution), 1 ml. equivalent to 1 mg. of HgO. Dissolve 1.58 grams of mercuric nitrate monohydrate in 10 ml. of (1 plus 1) nitric acid and dilute with water to a liter. Iodate mash solution. hlix 60 ml. of nitric acid, 6 ml. of 30% hydrogen peroxide, and 200 ml. of 6% potassium iodate solution with enough water to make a liter of solution. PROCEDURE
The preparation of the solution for analysis should present no problems, except occasionally for a niobium and tantalum ore. illthough the medium for the precipitation of thorium will keep niobium and tantalum in solution, there may be a problem in preparing the solution of the sample in this medium without prior hydrolysis of niobium and tantalum. Two alternative procedures are given. The first procedure is the simplest but may fail on high-grade tantalates containing very little titanium. The second procedure is of general applicability. Procedure 1 (Ores and Silicate Rocks). hlix 0.0500 gram of a finely
ground iepresentative sample of the ore with 2 grams of sodium peroxide in a platinum crucible. For a silicate rock, use 0.3 gram of rock and 3 to 5 grams of sodium peroxide or potassium carbonate. Sinter the sodium peroxide niiyture (covered) in a small furnace. a t 460' =t20' C. for 1 hour (fuse if potassium carbonate is used). B true sinter with no attack on the platinum will be obtained if the sodium peroxide is fresh and dry. Place the crucible and melt in a 150ml. beaker containing 30 to 100 ml. of water. Cover the beaker immediately with a watch glass; the dissolution reaction may be vigorous. Digest the solution on a steam bath for 15 minutes. Acidify with (1 plus 1) nitric acid, adding about 2 ml. in excess. Observe whether the sample is completely decomposed. The resuleti of this observation determine whether additional steps are required later. Add 1 nil. of ferric nitrate carrier solution. Add 1 or 2 drops of 30% hydrogen peroxide and then 50% potassium hydroxide solution to neutrality. Add 5 ml. excess for each 50 ml. of solution. Digest on the steam bath for about 15 minutes. Filter on a fast filter paper and wash the precipitate several times with potassium hydroxide wash solution. Drain the precipitate thoroughly by placing the p a h i of the hand over the funnel and pressing down. If incomplete decomposition of the sample was indicated above, wash the precipitate several times with ammonium nitrate wash solution. Disregard any cloudiness that may form in the filtrate. Reject filtrate. Ignite the precipitate in a small platinum or porcelain crucible and fuse with a small amount of potassium pyrosulfate. Leach the melt with 30 ml. of (3 plus 97) nitric acid solution. Add several drops of 30% hydrogen peroxide and then neutralize with 50% potassium hydroxide solution, adding 5-ml. excess for each 50 ml. of solution. Digest the precipitate on the steam bath for 15 minutes. Filter on a fast filter paper and wash with potassium hydroxide wash solution. Omit the foregoing steps, if complete decomposition was obtained. Pipet 5 ml. of water and 1 ml. of 8quinolinol into a 100-ml. beaker and place under the funnel. Dissolve the hydroxide precipitate as follows: d d d 1 ml. of 3% hydrogen peroxide over the precipitate, being careful to make the peroxide come in contact with all portions of the precipitate. When the hydrogen peroxide has drained, add 2 ml. of hot (1 plus 1) nitric acid slowly and dropwise to allow the acid to dissolve as much precipitate as possible. After the acid drains, add 5 ml. of hot water, playing the water over all surfaces of the filter paper. Repeat the sequence of peroxide, acid, and water twice more. Drain the funnel. Add all reagents and water with pipets to ensure proper concentrations for the subsequent iodate separation. Add 0.1 ml. of potassium iodate solution and 5 ml. of dtartaric acid solution. The solution is now ready for the iodate separation.
Procedure 2 (Ores). Follon. Procedure 1 through the first precipitation with potassium hydroxide (end of third paragraph). After washing with potassium hydroxide, wash the precipitate several times with ammonium nitrate wash solution. Ignite the precipitate in a small porcelain or platinum crucible and fuse with no more than 0.5 gram of potassium pyrosulfate until a clear melt is obtained. If sulfur trioxide is lost completely before sample is completely dissolved, cool the melt and add one drop of sulfuric acid to convert the sulfate to bisulfate. Heat gently and increase heat until a clear melt is obtained. Cool. Transfer the crucible to a 100-ml. beaker containing 15 ml. of water, 6 ml. of (1 plus 1) nitric acid, 5 ml. of dtartaric acid solution, 1 ml. of 8-quinolinol, 0.1 ml. of potassium iodate solution, and 3 ml. of 3% hydrogen peroxide solution, all added with pipets. Allow the melt to dissolve in the cold by stirring the solution. Remove crucible and rinse inside and outside with exactly 5 ml. of water from a pipet, adding the rinses to the beaker. The solution is now ready for the iodate separation. Iodate Separation. Add slowly from pipets, first 10 ml. of potassium iodate and then 5 ml. of the mercury carrier solution, stirring the solution during each addition. Place the beaker in a n ice bath and allow t o stand for 45 minutes. Stir in a small amount of paper pulp and filter on a slow (No, 42 Whatman or equivalent) 7-em. filter paper. Wash the precipitate thoroughly six to eight times with ice-cold iodate wash solution (25 to 35 ml.). Wash further if the sample is known to contain large amounts of titanium, niobium, or tantalum. Disregard any cloudiness or small precipitate that sometimes forms in the filtrate. This is due to post p r e cipitation of mercury. Drain the precipitate and stem of funnel by pressing funnel with hand. Also drain the last drop from the beaker in which the precipitation mas made. Remove beaker containing the filtrate and substitute the beaker in which the iodate precipitation was made. Dissolve the precipitate from the filter with alternate additions of 5 ml. each of hot (1 plus 1) hydrochloric acid and 5 ml. of hot water. Repeat the cycle twice more. Drain the paper and funnel stem. Add 1 ml. of perchloric acid to the solution and evaporate the solution on a steam bath until it is colorless and fumes of perchloric acid appear. Place the beaker on a sand bath (170' to 190" C.) until the perchloric acid is completely evaporated (about 30 minutes). Cool. Careful heating at sandbath temperature is necessary to prevent the formation of an insoluble form of any zirconium that might be present. Add 2 ml. of (1 plus 1) hydrochloric acid and evaporate the solution on the steam bath until dry. Cool. The sample is now ready for the spectrophotometric determination of thorium ( 2 ) . Ordinarily, 2 to 60 y of thorium dioxide are determined in the spectro-
photoinetric pm;edure. If more tlian these amounts of thorium are present, an aliquot of the solution should be taken. The proper size of aliquot is estimated by comparing the siae of the iodate precipitate obtained prior to the addition of the mercury carrier against thorium standards similarly precipitated. The blank correction for each batch of reagents is obtained by carrying about five water samples through the iodate separation and spectrophotometric determination and averaging the results. Ordinarily, the blank correction amounts to an absorbance of about 0.005. EXPERIMENTAL DATA
The conditions adopted for the iodate separation require a total volume of solution of 50 ml. containing 3 ml. of nitric acid, 3 grams of &tartaric acid, 0.3 ml. of 30% hydrogen peroxide, 2 mg. of ferric oxide (added as the nitrate), 5 mg. of mercuric oxide (added as the nitrate), 5 mg. of 8-quinolinol. and 0.6 gram of potassium iodate. These conditions permit the presence of a t least 500 mg. of potassium pyrosulfate without loss of thorium through formation of sulfate complexes. Effect of Variables. IODATE AND NITRIC ACID CONCENTRATION. The solubility of thorium iodate increases with increase in acidity or decrease in iodate concentration. The ideal balance should allow complete precipitation of thorium and yet minimize the coprecipitation of foreign ions. The recommended combination of acidity and iodate concentration is one of many fulfilling these objectives. The sensitivity of the recommended system to changes is best illustrated by the fact t h a t if more t h a n the recommended amount of nitric acid is present, 2 ml. of excess iodate solution are required for each milliliter of excess nitric acid to precipitate the thorium completely. .4t the 500-7 level of thorium dioxide, an increase of either 1 ml. of nitric acid or a decrease of 2 ml. of 6% potassium iodate results in a 77& loss of thorium. MERCURY CARRIER. Greater amounts than recommended result in increased coprecipitation of foreign ions; stoichiometric amounts of halides-to form, for example HgClz-completely prevent precipitation of mercuric iodate; thus halides must be absent. HYDROGEN PEROXIDE.Only slightly more than the stoichiometric amounts required to form the peroxy compounds of niobium, tantalum, and titanium are required. Amounts much greater than recommended cause the precipitation of a peroxy compound of zirconium, especially when 10 mg. or more of zirconium are present. KO more than 0.5 ml. of 300/, hydrogen VOL. 2 9 , NO. 5, M A Y 1957
849
peroxide should be used, preferably less. 8-QUINOLINOL.The concentration of 8-quinolinol is less critical than that of any of the other reagents. Although 5 mg. are recommended, 0.5 to 50 mg. may be used. &TARTARIC ACID. Tartaric acid delays the precipitation of thorium iodate. However, the concentration can be increased by a factor of 50% over the recommended amount without affecting the recovery of thorium, if the recommended 45 minutes are allowed before filtering. A few drops of potassium iodate are added before the tartaric acid to prevent the reduction of iron which would otherwise take place in the presence of peroxide and absence of iodate. Table I illustrates the results obtained on the recovery of 2.44 to 1950 y of thorium dioxide in the presence of 30 mg. each of the oxides of zirconium, cerium(III), titanium, niobium, tantalum, iron(III), or scandium; 50 mg. of iron(II1) oxide, and 15 mg. of tantalum oxide-each element tested separately. Also shown are the recoveries of the same amount of thorium in the presence of a mixture of 5 mg. each of the oxides of zirconium, cerium, titanium, niobium, tantalum, iron(III), and scandium. As no more than a 50-mg. sample of thorium ores containing these constituents is used for analysis, the experiments provide a good basis for the applicability of the separation procedure to the determination of thorium in such ores. The recoveries shown are satisfactory. Rare earth elements other than cerium were not tested because cerium is most likely to coprecipitate; the yttrium earth iodates are appreciably more soluble than the cerium earth iodates and substantial amounts of yttrium earths may be present without interference in the spectrophotometric determination of thorium. Other ions t h a t form insoluble iodates were not tested. Some (lead, bismuth, and mercury) can be tolerated in large amounts in the spectrophotometric determination; others (tungsten and bismuth) are soluble in the proposed tartaric acid medium; still others are separated during preparation of the sample solution-for example, tungsten and tin are separated as the soluble tungstate and stannate in the sodium hydroxide precipitation. The remaining tin is removed as insoluble metastannic acid by fuming with perchloric acid in the last stages of the analysis. The excellent recoveries shown in Table I should not be interpreted as proof that thorium &as completely separated from the elements tested. The determination of thorium was made spectrometrically by a method that tolerates the presence of several milli850
ANALYTICAL CHEMISTRY
Table 1.
Recoveries of Thorium in Presence of Various Elements
Tho2 Bdded, Elements Tested, Mg. (as Oxides) Blank 30 ZrOp 30 CenOa 30 TiO2 30 NbsOj
2.44
6.10
30 Ta20s 15 TazO, 50 Fe20s 30 Fez03 30 SczOa
5.91 6.02 5.85 6.35 5.95 6.37 6.05 6.62 6.08 6.20
Mixture of 5 mg. each of oxides of Zr, Ce, Ti, Nb, Ta, Fe, Sc
2.66
6.13
grams of zirconium and iron(II), and 20 to several hundred micrograms of the other elements without interference ( 2 ) . Occlusion tests shovied that the amount of zirconium occIuded varied from 0.2 to 2 mg. of zirconium dioxide, depending on the size of the thorium iodate precipitate and the amounts of zirconium tested (for thorium the rvnge tested was 2 y to 2 mg. of ThOz, for zirconium 2 to 30 mg. of ZrOz). Occlusion was highest for highest thorium. Similarly, the amounts of iron occluded varied from 200 y to 1.6 mg. of Fe203. For microgram amounts of thorium, less than 200 y of ceric oxide mere occluded when 30 mg. n-ere added and less than 20 y of titanium dioxide from 30 mg. of titanium oxide tested. The amounts of niobium and tantalum occluded were estimated to be less than 200 y of each. These elements are further separated during the perchloric acid fuming. Xo tests were made on the extent of scandium occlusion. TEST OF PROCEDURES
Several representative ores were analyzed according to the procedures out-
Test of Procedure on Ores
Sample Black sand 1 Black sand 2 Monazite la Monazite 2 Zircon 1 Zircon 2 Polycrase euxenite Eschynite Thorite Thorianite
y
48.75
390 0
1950-
Tho2 Found, 2.18 2 50 2.25 2.48 2.37 2.13 2.30 2.36 2.60 2.80
Table II.
24.38
ThOz, 7% Other New method method 4.00 4.05 2.13 2.16 9.65b 9.84 4.24 4.26 0.065 0.065 0.15 0.15 5.47 5.44 6.28 6.27,6.22 1.94 2.16 1 . 7 2 1.77
a New Brunswick AEC standard monazite. b Certificate value.
.
24.4 24.3 24.5 23.9 25.2 23.7 23.6 24.8 24.3 23.9
47.5 47.9 48.2 47.8 47.6 46.5 47.2 49.4 48.9 48.1
386 393 396 389 394 387
1950 1940 1920 1940 1960 1920
394 389 388
1960 1940 1920
25.3
48.6
397
1950
lined. The results are compared in Table I1 with those obtained by careful gravimetric analysis using standard methods. The zircon samples were analyzed according to the spectrophotometric procediiie of Cuttitta (1). The method for silicate rocks was tested on a standard diabase W-1 (5) containing about 0.0003% of thorium dioxide, to which known amounts of thorium were added. Two unspiked samples were included and the average absorbance obtained for these blanks was subtracted from the absorbances given by the spiked samples. The results are given in Table I11 in terms of the per cent of thorium dioxide that would be present if only the spike were considered.
Table 111.
Test of Procedure on Silicate Rock
Tho,, % Added
Found
0.00081 0.0020 0.0049
0.00095 0.0021 0.0048 0.0079 0.0097 0.019
0,0081 0.0097 0.019
The silicate rock procedure also was tested on three counting standards obtained from the AEC S e w Brunswick laboratory, as mixtures of a stand-
Table IV. Test of Silicate Rock Procedure on Monazite-Dunite Mixtures
ThOn, 70 Present
Found
0.0011 0.011 0.023 0.057 0.11 1.14
0,0014 0,012 0.022 0.055 0.11 1.10
ard monazite in a dunite base (Table IV). A sodium peroxide sinter was used to decompose the samples. LITERATURE CITED
(1) Cuttitta, Frank, U. S. Geological Survey, personal communication. (2) Fletcher, M. H., Grimaldi, F. S.,
(3)
(4) (5) (6)
Jenkins, L. B., ANAL. CHEM.,in press. Kronstadt, R., Eberle, A. R., U. S. Atomic Energy Comm. RMO-838 (1952). Meyer, 'R. J., 2. anorg. Chem. 71, 65 (1911). Schlecht, W. G., ANAL. CHEM. 23, 1568 (1951). Stine, C. R., Gordon, L., Zbid., 2 5 , 1519 (1953).
( 7 ) Tillu, M. M., Athavale, V. T., Anal. Chim. A d a 11, 62 (1954).
RECEIVEDfor review August 15, 1956. Accepted December 15, 1956. Publication authorized by the Director, U. S. Geological Survey. Part of a rogram conducted by the U. S. Geologicay Survey on behalf of the Division of Raw Materials, U. S. Atomic Energy Commission.
Paper Chromatography of 3,5-Dinitrobenzoates of Alcohols E.
SUNDT and M. WINTER
Research laboratories, Firmenich & Cie., Geneva, Switzerland
,The separation and identification of the 3,5-dinitrobenzoates of some primary, aliphatic alcohols in the range CIto Clz are described.
T
3,5-dinitrobenzoates are very commonly used for the identihation of alcohols. The separation of these derivatives by paper chromatography however, has been little investigated. Rice, Keller, and Kirchner (4) used a 20% aqueous dioxane solution among other solvents, for the separation of the 3,5-dinitrobenzoates of some alcohols, but stated t h a t a mixture of methyl, ethyl, propyl, and butyl 3,5dinitrobenzoates showed only two spots on development. One spot had a n R, value of 0.75 for the methyl 3,5-dinitrobenzoate, and the other large spot, with its center at a n R, of about 0.9, was believed to represent a mixture of ethyl, propyl, and butyl 3,j-dinitrobenzoates. A better separation was obtained by Meigh j2), who used the two-phase system methanol-n-heptane. However, the high volatility of the solvents is a disadvantage of this method. B y adapting the two-phase system HE
that a n important factor in obtaining good results was the saturation of the atmosphere in the chromatograph chamber with the vapors of the stationary phase (dimethylformamide) as well as with those of the mobile phase (Decalin). This also seemed to be the case in the separation of the 3,5-dinitrobenzoates of the alcohols as described in detail below. EXPERIMENTAL
Schleicher &- Schiill chromatographic paper No. 204313 was immersed in a 50% solution of S,N-dimethylformamide Werck) in acetone, followed by drying at room temperature for a short time to evaporate the acetone. The 3,5-dinitrobenzoate samples in chloroform solution (1 mg. per ml.) were applied to the dimethylformamide-impregnated paper in the normal way by means of a micropipet in quantities of 10 to 100 y. Thereafter the paper sheet was placed in the chromatograph developing chamber for about 12 hours for saturation at 25" C. (without filling the trough with the mobile phase). The correct saturation of the atmosphere in the developing chamber proved to be of great importance to the results obtained. I n a 38 X 30 X 54 em. dimethylformamide-Decalin(decahydr0- chamber both the side walls were covered with filter paper sheets (about 25 X naphthalene), first used by Horner and 45 em.) kept moist with dimethylKirmse (1) for the paper chromatogformamide previously saturated with raphy of the 2,4-dinitrophenylhydraDecalin. Two crystallizing dishes filled zones of aldehydes and ketones, the with the mobile phase were placed on authors obtained a very satisfactory the bottom of the chamber. separation and identification of the After having been kept for about 12 3,5-dinitrobenzoates of some primary, hours at 25" C. in a chromatograph chamber, the atmosphere of which had aliphatic alcohols in the range Cl to been saturated with both phases as deC,?. scribed above, the trough was filled with I t a n earlier stage and with excellent the mobile phase, Decalin (blerck) results, the authors had adapted the previously saturated with dimethylmethod of Horner and Kirmse ( 1 ) for formamide, and the chromatogram was a great variety of 2,4-dinitrophenylhydeveloped, using the descending techdrazones of aldehydes and ketones. It nique. The mobile phase traveled about had been their experience, in working 35 em. in 7 hours. The finished chroa i t h the 2,4-dinitrophenylhydrazonesJ matogram was dried a t 60" to 70" C.
I n spite of the fact that the 3,j-dinitrobenzoates of the alcohols examined are colorless, it was unnecessary to spray the chromatograms with 1naphthylamine, as described by Rice, or to use the Keller, and Kirchner (4, procedure of Meigh ( 2 ) with Rhodamine 6 G B S in order to reveal the spots. Simply hanging the dried sheets in the daylight for 1 to 2 hours or irradiating them under an ultraviolet lamp for 10 to 15 minutes resulted in the formation of distinct violet spots. About 5 to 10 y of a 3,5-dinitrobenzoate were easily detectable in this manner. -4 very satisfactory method for the examination of a chromatogram was to place it on a support consisting of another filter paper sheet, which had been made strongly yellow fluorescent by immersing it in a n 0.1% alcoholic SOlution of fluorescein made alkaline with a 10% aqueous potassium hydroxide solution, and examine the chromatogram under ultraviolet light. As a n ultraviolet source, a Philips mercury vapor lamp, HPTV 125 W, was used, which produced light mainly in the region of 3655 A. The ultraviolet lamp was placed about 40 to 50 em. in front of
Table I. R, Values of 3,5-Dinitrobenzoates of Some Aliphatic Alcohols (Ci Cn)
-
Compound Methanol Ethyl alcohol 1-Propanol 2-Propanol Sorbic alcohol 1-Butanol 1-Hexene-3-01 1-Pentanol 1-Hexene-2-01 1-Hexanol 1-Nonenol Lauric alcohol
Rf 0.21 0.40
0.50 0.52 0.55 0.64
0.69 0.72 0.73 0.79 0.86 0.92
VOL. 29, NO. 5 , M A Y 1957
851
