CATHODIC . I S D S S O D I C D E P O S I T S O F IROS C O M P O C S D S
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SCHMITT,
F.
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o., B E I R , R. s., i S D PLLMER, K. J.: J. C'ellular Comp. Physiol. 18, 31
(1941).
(24) S ~ E D B E RT., G , . ~ S D PEDERSE?;, K. 0.: T h e Cltraceirtrzfuge. T h e Clarendon Press, Oxford (19.10). (25) WRINCH,D. M.: S a t u r e 160, 270 (1942); and many other articles.
O S SOME COMPOUSDS OF IROS DEPOSITED O S BOTH POLES SI3IULTASEOCSLT GEORGE h S T O S O F F Chemzstry Department, Fordham Unaversaty, .Yew 1-ork, S e w Y o r k Recezved September 28, 1943
K h e n finely divided natural ores containing iron TI ere suspended in acidified water and a current applied, a deposit appeared on the platinum anode (1). In thin layers, this deposit had the appearance of gold. -4lthough not qoluble in dilute acids, the deposit could be stripped by a misture of dilute acid and hydrogen peroxide with an evolution of gas. Besides iron, there nere large quantitieq of calcium, sodium, and other metals present in the deposit. I t contained no traces of the anion of the acid used for acidif) ing the bath. The deposit had a variable composition. The amount plated out n a s not proportional t o the current, i.e., it did not follow Faraday's lan . Pure precipitated iron hydroside suipended in acid solution gave no anodic deposit. However, ignited ferric oxide gaye tlepositq similar t o the one5 described above. When the ferric oside i i a s heated to red heat and quenched in n-ater, larger amounts of anodic deposits 11ere obtained. I t \vas thought a t first that high temperature is necessary in order to produce these results, but further experiments indicated that if the precipitate is simply dried, it acquires the property oi giving the same effect.. For example, if one takes crystals of commercial aluminum sulfate, cliswlve- them in n-ater, and filters the solution, an insoltilde pon (lei of wnie wrt of iron oside remainion the filtei. This oside suspended in ncidulnted 11 atel inn\- giye effects similar t o those derciibed above. -1sample of ferric oxide may contain only minute traces of impurities but by thiq procedure, lead, manganese. and other metals 11ere estracted in appreciable quantities. For one series of experiments ferric oside \vas made from material which contained no inanganese (llerck analysis : manganese, 0.000 per cent). Hou-ever, qualitative tests of the anodic deposit shoved traces of manganese. These phenomena are easily reproducible. The piocedure u-as as follon-s: 30 g. of ferric oside uas suspended in 2 liteis of uater and 2 cc. of concentrated sulfuric acid added. The misture was itirretl mechanically and heated t o G O T . The degree of acidity of the bath \\as of no importance; it x a q only nece+sarj-to keep it acid. Platinum electrode. ( 2 in. x 2 in.) were inserted and
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GEORGE . I S T O S O F F
a current pa.+ed. There n no set voltage. Some of the experiment> \\-ere performed \\-ith GO volt.. qome \\it11 150 volt,, and in qome cases 6 volts was sufficient. I n m0.t of the espetiment* the current v-a. about 2 ampereq, but thi. a1.o varied. For .tri;)ping. a Inisture of equal volume. of dilute hyclrochloric acid and 3 pel cent hydrogen perositle I\ a- u4ed time- it a- necesqary t o change the amount* of acid 01 hydrogen peroxide. oning to the variable compoLition of the depoiit In thi. proce- a u n i l a r depo-it n a q noticed on the cathode, but it n a b uwally masked by large quantitie.; of othei matter IThich \I a- deposited cataphoretically. Hon-ever, T\ hen the cathode nas in.erted in a porous cup, a deposit \vas obtained which \\-a. 4milar to the anodic depo and T\ hich alio decomposed hydrogen peroxide. K h e n the current density 11 increased 11~-decreacing the size of the cathode, the deposit became grayish in .pot-. K h e n the electrode was reduced to the size of ]\-ire, the entire deposit \\-a< gray and I\-a+ easily recognizable as metallic iron. On the inner wall of the porous cup there n-as a brown deposit which 11-asscraped off. I t was different from the substances found on the anode or cathode, for it did not decompose hydrogen peroside. It was difficult t o do a satisfactory analysis of the non-metallic content of the deposit, because it could not be easily detached mechanically from the platinum anode. For the metallic analysis. strippings 11 ere accumulated from many depositions in order to have sufficient material. The weight of the material deposited was obtained by \I eighing the platinum before and after deposition. The platinum itself lost no neight.’ Becauqe of the variable nature of the deposit, the analysis gave only a rough indication of its composition. I n all cases, the weight of the metals piesent in the deposit was less than the total weight of the material .tripped. The difference can only be osygen or possibly hydrogen. There was no evidence of water of hydration. The deposit was stable up t o the beginning of red heat. I n a stream of hydrogen, the deposit \vas reduced and a gray mass resulted n-hich evidently was iron. This iron would not dissolve in acids quantitatively. It is the belief of the author that these deposits are of the nature of peroxides Tvhich, as a rule, decompose hydrogen peroside. They are of complex and variable composition and may be deposited on either the anode or the cathode according t o conditions. This can be esplained by assuming that the particle of a fairly complex matter has a certain dipole moment, the position of which may be not the same in difThus in one case the negative pole may be nearer the ferent configuration.. periphery, and the particle n-ill -tick to a positive ion of the acid used and Tvill go the cathode, and izce iersn. On the basis of chemical analysis of various deposits, it v a s not po-ible to conclude nhether they consist of any new substance or of a mixture of substance,, in vien of their ...arinbleconiposition. At this point, nithout reeing TI hat elhe could be done under the circumstances, the author coniniuiiicated TI ith the late Dr. I-I. Freundlich. The latter found these 1 I t is therefore improbable t h a t the ion of platinum participated in the formation of these deposits, ss some people may think.
VISCO>iTT OF G.1SES A S D TAPORS
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re.xlts extremely interesting :ind suggested that s-ray method night t h r o x some light on the subject. The nutlior rhought that Dr. Freundlich might be the 4 t a b l e man to carry through this piece of work, hut hi udden and unexpected cleatli interrupted the correspondence. The author then took advantage of the kindness of the General Electric Company, which expressed n rvil1ingnes.i t o perform the3e experiments. Samples of both cathodic and anodic deposits xvere submitted t o them. The results olitained, 1ioTves-er, did not explain anything. They IT-ere examined by Dr. C. J . Darisson of the Bell Telephone Po., t o n-hom the author wishes to espress thanks, but he could not draw any conclusion from them. I n view of the great interest attached t o this problem the author wishes t o publish these results as they are, n i t h the hope that investigators having suitable facilities n-ill w m t t o Tvorli in this field. REFERESCE
(1) ANTOXOFF,G . : Iiolloid-Z. 79, 331 (193i).
T H E V h R I A T I O S OF T H E 1-ISCOSITI’ OF GhSES -1SD 1-APORS WITH TEIIPERAITLTRE KILLIAM L I C H T , JR.. AXD D I E T R I C H G . S T E C H E R T Department of Chemical Engineeririg, L-nirersity of Cincinnati, Cincinnati, Ohio Receiced J u l y 26, 1949
Fruitful studies of the viscosity of substances in the gaseous state have been carried out for the past century. The results of these studies have been of both theoretical and practical importance. Esperimental determinations of the coefficient of viscosity of pure subntances as a function of temperature, pressure, and the nature of the molecules making up the substance have led t o elaboration and modification of the classical kinetic theory of gases and t o a more T h e symbols used in this paper a r e given below: = characteristic constant in the esponential equation, = characteristic coiistant in T r a u t z ’ s equation, = characteristic constant in Yutherland’s equation, C’ = characteristie constant in Reingniium’s equation, D = characteristie constant in Yutherland’s modified equation. d = characteristic constant in T r a u t z ’ s equation, G = constant characteristic of :I s a b s t a n c e ; dependent upon molecular weight, critical temperature: and pressure. J = characteristic constant iii Jones’ equation, fi = charncteristic constant in Piutherland’s equation. I
