IBS XBOPPIHG GALLIUM ELECTRODE

II PUSBD SALTS

APPROVES;

^ u

fjci .Professor

f > / si ,? " 7 //f--)

A/* , K ^ " " in' Ill I wi*i|Mpii)wiifiiwi'wwlfe'r>n» vrliriiiiitiiiiini' -inirfwnimnrfSnwr inmnmirii i fwirriir irnilrrr-iiir-TrriTir--iiiir(irvirr-rfrVmiiirf"rifiiti

linor professor I/1:

"TF

. , / , S i i i l f t T w V i i l l * l l i l < ! I III. I I j i t f t ^ i i w H g i l i Ill

Dira ton-jof the Department of Cfaemistry

Dean of the Graduate School'

THE DROPPING GALLIUM SLECTROUE

II FUSED SALTS

THESIS

Presented to the Graduate Council of the

North Texas State University in Partial

fulfillment of the Requirements

for the Degree of

MASTSR OF SCIEHCE

By

D. Kent Dickie, A,

Denton, Texas

January, 1966

TABLE OF CONTESTS

Page

LIST Of ILLUSTRATIONS . iv

Olaapter

I. INTRODUCTION . 1

II, EXPERIMENTAL PROCEDURE . . . . . . . 7

III. RESULTS AJTC) DISCUSSION 13

BIBLIOGRAPHY . . . . . . . . . . . 27

i i i

LIST Of ILLUSTRATIONS

Figure Page

1. TJi© Dropping Gallium Electrode 9

2* Current-voltage Curve for Dropping Gallium Electrode vs. P"t Reference • in LISO3-IIO3 Eutectic at 180°C U

3. Current-voltage Curve for Dropping Mercury Electrode va Pt Reference in LHO3-KIO3 Butectic at 180°C 15

4. Current-voltage Curve for Dropping Gallium Electrode vs Pt Reference in LiCl-KCL Eutectic aST450°C 17

5. Polarographic Wave for LINO3-KHO3 Eutectic Containing Gallium Nitrate and Nitric Acid . . 19

6. Polarographic Wave for LINO3-KNO3 Eutectic Containing Lead (II) . . . 21

7. Heyrovaky-Ilkovic Plot for Data Obtained From Polarogram of I1UO3-IIO3 Eutectic Con-taining Lead (II) . 22

iv

CHAPTER I

INTRODUCTION

In 1922, Heyrovsky (9) provided a novel interpretation

of the current-potential carves observed for the dropping

mercury electrode (DEB). Most important in this interpre-

tation was the establishment that the limiting current

varies direotly in proportion to the concentration of the

solution

kd = kC.

Initially, this method was an empirical procedure*

In time it was supplemented with a quantitative theory

which made possible the interpretation of current-potential

curves by means of physical concepts related to diffusion in

the electrolyte and characteristics of the mercury drop.

This new field of electrochemistry was called polarography.

While current-potential curves can be measured with a

solid platinum microelectrode, the electrode lacks several

of the advantages of the MS* The 1MB reaches a steady

state more rapidly after a change in potential? the freeh

exposure of electrode surface allows the current to be in-

dependent of the previous history of the electrode, and the

current-potential curves obtained with the DIE can be treated

mathematically more eaaily by the Heyrovsky-Ilkovic equations

1

b M B - sl/2 - H l o g|!

where Rf equals .059 volts at T 298°K, a equals the electron -f

change, % equal® the diffusion current, and BTMB ®»d i e$ual

the applied voltage- and resulting current respectively.

Us© of the DUB in fused salts was reported in 1943 by

Steinberg and lachtrieb (10) who reported reduction waves for

Hi*"* , Cu**, Bi++ in the IH4IO3- MIO3-SH4OI eutectio at 86°G.

Steinberg and Eachtrieb (11) reported in 1950 that reduction

wa' es for Hi** , Cd+*, Zn++, and Fb , obtained with the M B

in LiHOj-KMO^-lalOj eutectlc at 160°C, obeyed the Ilkovio

equation. Christie and Qsteryoung (2) utilised the 1MB for

a polarographic study of the ciiloro-complexes of PbHi 4" 4",

and Cd** in th® LiNO -KIO eutectic at 180°C. Suzuki and co-

workers (12) have reported M B polarography in the LiCl-KCl-

A101 ©utectic at a temperature of 160°C. fell-defined re-

duction wives were reported for lb*"1", Cd**( and Zn** which

were found to obey the Ilkovic equation. Use of the M S in

fused salts is limited to investigations below about 220°C

due to the increased volatility of mercury at temperatures

above this value.

Difficulties encountered with solid electrodes (poisoning

of electrode surface and slow response to potential change)

are jasgnified in fused salts. This ha a led to investigations

of otter metals as substitutes for mercury at high temperatures,

Steinberg and Nachtrieb (11) in their work on dropping

electrode polarography in fused salts tried dropping lead

and dropping bismuth electrode® but reported these electrodes

became inoperable after several second® due to the clogging

of the capillaries. An attempt with, dropping silver in borax

at 1000°C produced erratic polarograms. Hewand Egan ($}

reported that the dropping bismuth electrode could be operated

reproducibly if the drop time was controlled by a positive

gas pressure on the liquid metal* They reported polarograms

for Cd++, Pb++, and Znt+ in the LiCl-KCl eutectic at 450°C

and a diffusion current of 5«A for the pur© melt.

Gallium, which has the unique property of being a' liquid

between 30°C and 2000°C t has been investigated by several

groups. Crabb (3), as quoted in Dissertation Abstracts# at-

tempted aqueous electr©capillary studies but reported that

the tendency for gallium to oxidise in aqueous solutions was

a Major problem. Glguer# and Lamontage (6) studied the drop-

ping gallium electrode (DGE) in aqueous solutions but found

that it behaved eratieally due to oxide formation, and pro-

duced no reproducible curves. They reported a residual

current of 50uA with a gallium drop fives times larger than

the mercury drop, lo reduction waves were attempted.

Graham (7) reported that the use of a larger oapillary

and an acidic solution overcame the oxide problem. He re-

marked that the BCKE was a useful research tool and recommended

a methanol solvent rather than water. Frumkin and co-workers

(4, 5) published several papers on electrocapillary studies

of gallium in which control of pH and voltage allowed them

to overcome the oxide problem. They found that the oxide-

forming tendencies increased as the electrode was charged

more anodioally and that it became more pronounced near the

electrocapillary maximum. Increasing the acidity of the

solutions minimized the oxidation allowing a larger voltage

span to be utilized. Pruufein (5) noted that larger errors

aay be introduced if the gallium used is of insufficient

purity. Slectr©capillary studies of gallium in fused LiCl-

KC1 have been reported by Bukum and Ukshev (1).

This gaper is an attempt to appraise the usefulness of

the D&E in fused LiNOj-KHOj, to compare it with the M B , and

to study the M B in fused LiCl-KCl.

CHAPEEB BIBLIOG-HAPHY

1. Bukun, 1. and S. Ukshev, "Electrocapillary Phenomena on Gallium in fused liCl-K01f

w ihurnal Pizicheskoi Khimii. XXXVII (1963), 1401.

2. Christie, J. 1, and R. A* Osteryoung, "Polarographic Determination of Formation Constanta of Complex Ions in Fused Journal of the American Chemical Society, LXXXII (April, 19&)), 1841.

3. Crabb, H. T., "Electrocapillary Measurements at the Gallium Electrode," unpublished dissertation, Department of Chemistry, Ohio State University, Columbus, Ohio, 1962, Dissertation Abstracts, XXII (1962), 3562-3364.

4. Frumkin, A.t 1. Grigriev, and I, Bagotateyn, "Electro-capillary Measurements Using the Gouy Capillary Electrometer," Doklady Akademik Nauk USSR. CLVII (1964), 957-963. — '

5. Frumkin, A., J. Polianoiskaya, N. Grigoriev, and I. Bagotskayn, "Electrocapillary Phenomena on OaIlium," •Electrochiaioa Acta, X (August, 1965), 793-805*

6. Giguere, P. A. and D. Lamontage, "Polarography With a Dropping Gallium Electrode»»• Science, CXX (March, 1954), 390-392.

7. Graham, D. C., "Analytical Applications of Electrical Double Layer Measurements," Analytical Chemistry# XXX (Hovember, 1958), 1736-1741."" ^

8. Heue, R. J., and J. J. Egan, "Fused Salt Polargraphy Using a Dropping Bismuth Cathode," Journal of Electro-chemical Society, CVII (October, I960),824^53?: '

9. Heyrovsky, J., ^Processes at the Mercury Dropping Cathode," Chemicke Listy. XVI (1922), 256-271.

10. Steinberg, M. A., and 1. H. lachtrieb, "Characteristics of the Dropping Mercury Electrode in Fused Salts," Journal of the American Chemical Society. MX (August, 1948),

XI, Steinker in Fuse Society»

12. Suzuki, M

T M. A.f and N. H» Nachtrieb, "Polarography Salts ,n Journal of the American Chemxoal LXXII (Auguai, l55"Oj7~355S-3567.

Hidehiro, and S. Goto, "The Dropping \lA£V.*i» f m# p mm V I iiiu Q • WM Wf * XXW JJFUJ/jXZig Mercury Electrode in Molten MCI-KCI-AICI3,» Journal

focigty of Japan, Pure Chemistry Section,

CHAPIER II

EXPERIMENTAL PROCEDURE

An inert atmosphere box constructed lay S. Blickman, Inc. ,

Weehawken, lew Jersey, was used for ail M B work* Materials

were introduced into the box after the entrance port bad

been evacuated to a pressure of ten microns and flushed

with nitrogen several times. While the atmosphere was not

circulated, the box was evacuated periodically to twenty-

five microns and flushed with nitrogen three times. The

nitrogen used was nominally 99-99 per cent pure and was

used without further purification. Metallic sodium was ex-

posed in the box to remove trace impurities. As the work

progressed it became apparent that the level of oxygen and

water vapor in the box atmosphere was high enough to cause

some interference with the work, but available methods for

changing the box*s atmosphere and desiccation were not ade-

quate.

Reagent grade chemicals were used in all cases without

further treatment except drying, four hundred grams of 99.99

per cent gallium supplied by "Reanal" finomvegysaergyar

Budapest, Hungary, were available for this investigation.

About twenty-five grams of gallium were needed to produce a

polarogram. The LiNO^-KNO^ euteetic system (38.6 mole fo

7

LllO^t mp 139°C) was prepared from oven-dried materials.

After the euteotic had teen mixed and fused,, it was stored

under desiccation at room temperature for twenty-four hours

"before it was introduced into the "box. All metal ions were + «|r

added to the melt as the nitrates except Od and Ba which

were added as the chlorides; Ca** was added as the carbonate + 4 "V

and I& was added as the oxide.

She melt was contained in an eight inch Pyrex test tube

which was heated by a Vycor tube furnace (3 x 20 cm) wound

with nichrom® ribbon covered with asbestos cord, and fitted

into a larger diameter tube. A temperature of 18Q»30Ot as

measured by a mercury thermometer dipped into the melt, was

maintained by varying the potential on the nichroaie ribbon

with a rheostat. Initially, a silver-silver chloride electrode

(1) was used as a counter electrode. It consisted of silver

wire placed in a Pyrex tube containing eutectic saturated

with AgCl, and containing 3.86 milligrams of K.C1 per gram

of eutectic. This was in contact with the system through a

fritted glass disc in the end of the tube. later, a platinum

strip (8 x 50 mm) was used as a counter electrode. The liquid

electrode reservoir (see figure 1) was fabricated from Pyrex

glass.

fhe procedure required to produce M E polarograrns was

somewhat awicward and tedious. Solid eutectic was added to

the test tube and brought to furnace temperature; an approximate

6a INLET

Pt CONTACT TO Ga

TYGON CONNECTION

INLET

fig. 1—The dropping gallium el#etrode

10

amount of metal salt was added, and the system was allowed

to equilibrate. Dropping of the J3GS was initiated by positive

nitrogen pressure on the gallium contained in the reservoir.

On several occasions it was necessary to continue this pressure

to produce a uniform drop rate. When the polarograra was com-

pleted, the electrodes were removed and a sample of the melt

collected, The gallium colleoted in the tube during the

polarogram was returned to the reservoir and the melt was

then returned to the test tube. The ?yrex oapillaries varied

in length from 75 to 125 millimeters and were hand-drawn to

a bore of about 0.25 millimeters. They were fitted down to

a ground glass ball joint with Tygon tubing which facilitated

their changing when elogging occurred after several days of

use. Gleaning with aqua regia, following by a washing with

water, allowed them to be reused. Ordinary polarographic

drop time© of one to four seconds were- observed with a pres-

sure head equivalent to 90 centimeters of gallium.

Studies were also made using LiCl-KCl. The LiCl-KCl

eutectic (58.5 mole i» mp 359°G) was dried using the method

described by Maricle and Hume (2). A platinum strip (2 x 10

cm) was used as a counter electrode. The furnace was main-

tained at 450-5°C. Phosphorus pentoxide was used rather

than sodium to reduce the moisture level in the dry box. The

oapillaries used were of a smaller bore (.15mm) than those

used in the nitrate experimentation. Heavy walled Byrex test

11

tubes were used at this higher temperature because the thinner

walled Pyrex tubes proved unreliable when exposed to thermal

shock. About five grams of gallium was needed for a polar©gram*

She polarograms using the dropping mercury electrode were

run in the atmosphere with no attempt made to shield the melt.

In each run the procedure consisted of placing solid ©utectic

in a test tube and bringing it up to furnace temperature.

Polarograms were then run on the melt in the usual manner*

It was noted that flushing the melt with nitrogen for fifteen

minutes produced no visible change in the polar©grama obtained. .

All polarograms were recorded by.- a Sargent Model XXI Recording

Polarograph with a polarization rat® of 0.074 volts per minute

on a one volt apan and 0.222 volts per minute on a three volt

.span.

CHAPTER BIBLIOGRAPHY

1, Christie, J. H., and R« A. Osteryoung, "Polar©graphic Determination of Porsmtion Constants of Complex Ions in Fused Journal of th® American Chemical Society. LXXXII (April, I960), 1841-1847.

2. Maricle, D. L. and D. !• Hume, "A New Method for Preparing Uydroxlde-Pree Alkali Chloride Malta." Journal of the Electrochemical Society, CVII (April,

12

COUPTER III

RBSTOffiS AID DISCUSSION

A comparison of the residual current curves in MNO3-

KHO3 melt was made for tooth the USE and M B . The same plati-

num counter electrode m s used so that these curves could tee

compared directly (see Figure 2 and figure 3). The available

working range for the DGE (0.1V —•* - 1.24V vs J&uch

larger than the available working rang© for the USE {-O.06-*

— 55? va Pt). The electrocapillary maximum was .04? va Pt

for the 1MB and -.4¥ vs Pt for the DGE. Frumkin and co-

workers (3) found the difference between the electrocapillary

maximum for gallium and mercury to be .42 volts in the absence

of anion adsorption on the electrode surface and .17 volts

with equal surface charge. In consideration of this, he

interpreted the .35 volts difference between the electro-

capillary maximum of mercury and gallium in chloride melt to

indicate that the predominant adsorption of anions on gallium

ia more pronounced than on mercury. Our valu® for this dif-

ference, .44 volts, using the same consideration would indicate

greater adsorption on gallium in nitrate than on gallium in

chlorides. She largest residual currents were I32«jl at-1.24

vs Pt for the DGE and 0.32j & at -0.55 vs Pt for the DME. This

much greater residual current for the DGE is due to the much

13

14

+» PI

% u 4» 0 m H 0)

rH H

Oi 9

* 8 © H

O 4* O

fl» *P # Hi p r\ • o 4B « I * KN

7 -CM *H * 0> t«0 0 •h a ft ©

© ©

1 3 ^ 8 0 0

1 5

|f f"*f EA 0 0

(vrf) lNBayno

16

|pr«ater aur facte aran of t l» iplll iM -'irop {&gpr oxiuiat«3ly

100x)« a poaeible rougi* oeetlcg of Sa203 on tha surface sf

tb® trop could gr*fitly inereaaa tb« effeotivo surface ar t*

between the wirowrj dro* and tha g a l l i w dye#.

A 'residual currant ourtm for t t» 74.C1-&C1 autaotle mm

4#tar»laa<l for tb» 3SS (aaa Figur* 4). fit® available worteitsg

raoga m e -•2S? -.73? m Pi„ a»ct the vaxiaiMft raai£uai cur-

rant wa# 23uA» a t -75Y v« J?t. Tb» alaoiroeapillary tmximxm

was looat«4 a t -*26V. $l» reaidual current varied with drop

t i»c , but the voltaga raaaiasd constant. The addition of

HbCl to the a#It produced ao visible obange in tbo residual

current curva.

?b» »ucb aaallar residual ourrant ©an be axpl&inad by

'til© aaallar dropa a t the % in t&e chloride s a l t . HIS

polcu*ograpby 'las bee;. reported by Uusimi and oo-wosrMra (?)»

but t i» atoaaae* of a aeeasia ooualiar el®otr®d® uada eanyarlaon

of tba two impractical.

On botfc « a m g a w»va ia to ba noted a t about ttoa ©site

voltage of -0 * 4? iji i?t# $&ia wava, whiob i s mtioh star® pro-

nouncad on tJaw§ BSt* s t a r t s diraotly a f t a r tfaa alaotraaaylllavy

o x t e w a . TM® mm appear® to be the radtuetiott of log to 902",

f l » addition of .Kg* as tkw yotaaaiuoa sa l t ommm iim mm to

diaappaar abioh can b® explained by the reaotioti

®% 1%- HO5- 10

17

m »a o

0 -#3 m 1 *i4 iH

ML o o *3 Sk4» p c$ O

# *rl • 4* &§ •°s © 0) wj , {8 H •PO •if id

m -u « jU *HI

1 ® O

a N # #

m%4 *r4 # PH «4 4$ P* pi

(vW) i N a y y n o

18

as suggested by Topol, Osteryoung, and Christie (9). Sailte

nitrate (prepared lay dissolving gallium in nitric acid and

dehydrating) when added' to the melt produced a wave whose

rising portion occurred in this same region of potential

(see figure 5). fhe wave diminished with passing time, end

the curve became indistinguishable from the residual current

curve after a period of about two hours. It appears that

the gallium nitrate formed was not free of nitric acid and

that this aoid caused the reduction wave. This can be ex-

plained by a series of reactions suggested by fopol and co-

workers (9) as follows:

2I(>3~ -» 2N02 + 1/2 0 2 + 0*

2I02 + 0S->103"* + !02~

HC2 + I02*^I03~ * 1 0 •

fh® ©volution of nitrogen oxides which was observed at tM.s

time also indicates these reactions.

2hat this melt behaves as a strong oxidizing medium can

be shown by its effect on silver. A silver-silver chloride

electrode was initially used as a reference electrode, but .

the potentials of gallium oxidation of the extracapillary

uaximum, and of the melt decomposition were not reproducible,

fhe silver-silver chloride electrode was found to have the

same potential as an oxide-coated silver wire. Also* the

wire became brittle and quite fragile after immersion in the

melt. Platinum electrodes also became visibly corroded and

19

CO

UL

IA H

(v?Y) iN3yano

20

covered with a dark oxide-like coating which dissolved in

concentrated HOI. from studies in a chloride melt it appears

that this corrosion occurs only after the platinum has been

in direst contact with gallium. After testing two similar

strips of platinum, It was found that a strip dipped in

gallium arid placed in a LiCl-KCl eutectic melt corroded

markedly in a twenty-four hour period while a strip simply

placed in the inelt did not. However, the platinum electrode

served for the duration of the experimentation with a potential

reproducibility of about 0.02 volts.

A polar©graphic study of Fb++ was attempted with the B£*E|

and a wave TO® obtained (see Figure 6) which followed the

Heyrovsky-Ilkovic equation. Plots of log ( t $ p i — ^ D G S

yield straight lines (see figure 7) with n « 1.0* 0.2 and

E 1/2 - -.4-0 - .03? vs Pt. The wave height was time dependent.

Apparently the lead ion was involved in a reaction with the

melt to produce 102 which undergoes reduction, The appearance

of nitrite oxidation with the addition of halid© iasae has been

reported by Novlk and Lyalikov (6). On several occasions a

red precipitate was noted at the surface of the melt. In one

case a sufficient amount was Isolated to obtain an X-ray dif-

fraction pattern identifiable aa Pb304. The formation of

PfrjO could be explained by the following reactions

3Pb++ + 7N03~-» N02~ + 6NO2 + PbjO# + 3/2 02.

21

cc 5.0

E DGE vs Pt REFERENCE (V)

Fig* 6—Polar ©graphic wave for MHO3-KNO3 euteotio containing toad ( I I ) .

22

-0 .40

'DGE

-0.45 -0 -50

vs Ft REFERENCE (V)

fig. 7—Heyrovsky-Ilkovio plot, for data obtained from polarograra of hiEOj-KMOj eutectic containing lead (II).

23

She lOg would have dissolved In the melt,and this solution

was indicated by the yellow color observed at this time. The

appreciable solubility of N02 in nitrate melts M a "been re-

ported (8), In a separate experiment it was noted that the

red product not appreciably soluble in the tie It and

produced no color change.

Polarograma of Cu**, 2»++, La++ +, Ba+4> , Ca*+ Tl+ , Cd* ,

and Ag + were attempted, but no other waves were obtained. Prom

electromotive force information available (4, 5) all of these

ions except Cu*+ and Ag+ should have been reduced.

Barlow (1) reported a well-defined wave in the I»iCl-KCl

eutectic at 450°C. The ourve had a half-wave potential of

-.56 volts vs Pt, and it became indistinguishable from the

melt after twenty-four hours. Analysis of samples taken

from the gallium, and »®lt used by standard aqueous polarography

showed no lead ion in the melt, and a much higher concentration

of lead ion w e found in the gallium than would be expected by

the electrode reaction. Barlow (1) postulated that this was

due to an exchange reaction between the electrode surface and

the melt. Polarograms were obtained for Sn++, $a++'% and 2n++|

but no reduction waves were observed,

Gallium is so susceptible to oxide formation that it ap-

pears that the surface of the gallium drop is oxidized by the

nitrate melt and that this oxide coating hinders the reduction

of metal species at its surface (10). The lack of an anhydrous

24-

melt would also lead to gallium oxide formation. Bertozai (2)

bag reported high, water solubility in nitrate melts.

Work on the chloride melt as well as on the nitrate a#lt

could be greatly hindered by the impurity of the gallium used*

Frumkin and co-workers (3) have shown that the value for

electrocapillary curve heights differed "by forty-one dynes

per centimeter and that the value for electrocapillary maximum

differed by almost a tenth of a volt when one compared the

values obtained with 99*9999 per cent pure gallium and 99.996

per cent pure gallium* If there is an exchange reaction oc-

curring as postulated by Barlow (1), the values obtained from

the DGE would become increasingly sore inaccurate with the

length of use.

CHAPTER BIBLIOGRAPHY

1. Barlow, J. D., "Electrolysis in MC1-K01 Euteotio With the BrOffing Gallium Electrode," unpublished report, V. 8. I. Research Participation Institute for High School Teachers, Benton, North Taxa© State University, 1965.

2. Bertozzi, G., "Water Solubility in Molten Salts,1* Intended Abstracts of the Electrothernics arid Metallury Division, The SlecTrochimTca1 Society ISpFing, 19*>5>), lo8-0L71*

3. Prumkin, A n J. ,Polianoiskaya, If. Grigoriev, and I. Bagotskayn, "Slectrocapillary Phenomena on Gallium, Electrochimica Acta, X (August, 1965), 793-805.

4. Gurovich, E. 1. and M, D. Matueeva, "Electromotive Force Series in Molter: Salts,"' Jhurnal Analiticheskoi Khimii, XXXVII (1965), 974-978. ^ ~ "" ^ ^ *

5. Laitinen, H. A. and C. H. Liu, "An Electromotive Force Series in Molten Lithium Chloride-Potassium Chloride Eutectic,* Journal of the American Chemical Society, LXXX (March, 1355) ,ToT5^LD2i:

6. Jlovik, R. M. and Yu S. Lyalikov, "Polarographic Deter-mination of Anions in Melts," Jhurnal Fizicheskoi Shiaaai, XXXIII (1962), 333-883T '

7« Suzuki, 5., M. Hidehiro and S. Goto,"The Dropping Mercury Electrode,*' Journal of the Chemical Society of Japan, Pure Chemical Section, UKSXltf (19&2),'883~88FT

8. Swafford, H. S., Jr. and P. G. McCormick, "A Yoltammetrio Study of the Oxidation of Iodide and Bromide in Potassium Hitrate-Sodium Nitrate Eutectic Melts,*1

Analytical Chemistry. XXXVII (July, 1965), 974-978.

9. Topol, I. B., J. H. Christie and R. A. Osteryoung, "Electrochemical Studies of Acid-Bases Equilibria in Molten Alkali Iitrate©,w Extended Abstracts of the Sleo trothermics and Metallury Mvision, The ETectro-oheaioai iocliTyTgprl'nE'; 207-212:

25

26

10. Wolf, Guenter, "Electrode Reactions on Solid and Liquid Gallium in Aaueous Electrolyte SolutionsZeitachrift fur Bhyaiteliscfae gfaemii, CCXXIII (1963), 2 W % W * "

BIBLIOGRAPHY

Articles

Bukun, I. and B. TJkshev, "Electrocapillary Phenomena on

Gallium in fused MC1-IC1," Zhurnal Fizicheekoi KMmli. XXXVII (1963), 1401-1409.

Christie, J. H. and R. A. Qsteryoung, "Polar©graphic Deter-mination of Formation Constanta of Complex Ions in Fused LiKOj-KNO^," Journal of the American Chemical Society. LXXXII (April, 196oI, 1841-1847.

Frumkin, A., J. Polianoiskaya, 1. Grigoriev, and I. Bagotsteyn, "Blectrocapillary Phenomena on Gallium," Sleotroohimloa Acta* X (1965), 793-805.

Frumkin, A., H, Grigoriev, and 1. Bagotskayn, "Eleotrocapillary Measurement® Using the Gouy Capillary Electrometer," Doklady Akademii Haul S8SR. CLVII (1964), 957-963.

Giguere, P. A. and B. I&aontage, «Polarography With a Dropping Gallium Electrode9

U Science. CXX (March, 1954), 390-392.

Graham, D. 0., "Analytical Application of Electrical Double layer Measurements,w Analytical Chemistry, XXX (Hoveatber, 1958), 1736.

Gurovich, 1. I. and If. D. Matueeva, "Electromotive Force Series in Molten Salts,w Jhurnal Analfiticheakol Khiimai. XXXVII (1965), 974-978.

Heu®, E. J. and J. J. Igan, "Fused Salt Polarography Using a Dropping Bismuth Cathode," Journal of the Electro-chemical Society. CVII (October, 19bOT7 S2T-533:

Heyrovsky, J., "Processes at the Mercury Dropping Cathode," Chemioke Listy. XVI (1922), 256-271.

Laitinen, H. A. and C. H. Liu, "An Electromotive Force Series in Molten lithium Chloride-Potassium Chloride Eutectic," Journal of the American Chemical Society. £XXX (March,

27

2'8

Maricle, 2). L. and D. I. Hume, "A Sew Method for Preparing Hydroxide-feee Alkali Chloride Melts," Journal of the Electrochemical Society, CVII (April,. I960), 354-359•

lovik, R. M. and Yu S« Lyalikou, "Polarographic Determination of Anions in Melts," Jhurnal Pizicheskoi Khiinmi, XXXIII (1962), 883-888.

Steinberg, 1. A. and N. H. Nachtrieb, "Characteristics of the Dropping Mercury Electrode in Fused Salts,H Journal of the American Chemical Society. M X (August, 1948), 2FT3-WE4~ 1

, "Polarography in Pused Sale's»'*""Journal of the American Chemical Society. IXXII (August, 1950), 5558-5567*

Suzuki, M., M. Hidehiro, and S. Goto, "The Dropping Mercury Electrode in Molten LiCl-KCl-AlClj," Journal of the Chemical Society of Japan. Pure Chemical Section, LXXXIII l(19i

l2)"","i"88,5«88S; ~

Swafford, H. 3., Jr., and P. G, MoCormick, WA Voltammetric Study of the Oxidation of Iodide and Bromide in Potassium Hitrate-Sodium Nitrate Eutectic Melts,« Analytical Chemistry, XXXVII (July, 1965), 974-978.

Wolf, Guenter, "Electrode Reactions on Solid and Liquid Gallium in Aqueous Electrolyte Solutions," Zeitschrjft fur Physikalisch® Chemii. CCXXIII (1963)» 249-259•

Publications of Learned Organizations

Bertozssi, G., "Water Solubility in Molten Salts," Extended Abstracts of the Electrothermics and Metallurgy Division, f m Slectrochiilcal Society (BgriBST W W ) , 118-1717

Topol, L. E., J. H. Christie, and R. A. Oateryoung, "Electro-chemical Studies of Acid-Bases Equilibria in Molten Alkali nitrates," Extended Abstracts of the Electrothermics and Metallurgy Division, lh#" llecirocEimlcal' Society (Spring, 1955); 207-212.

Unpublished Materials

Barlow, J. D., "Electrolysis in LiCl-KCl Eutectic With the Dropping Gallium Electrode," unpublished report, I. S. P. Research Participation Institute for High School feachers, Denton, North Texas State University, 1965.

29

Crabb, 1. T., "Slectrocapillary Measurements at the Gallium Electrode," unpublished dissertation, Dej>artment of Cherniatry, Ohio State University. Columbus. Ohio. 1962, Dissertation Abstracts, XXII (1962), 3362-3364*