209:
305:
In 1953 in
Stockholm IUPAC recognized that either of the conventions is permissible; however, it unanimously recommended that only the magnitude expressed according to the convention (2) be called "the electrode potential". To avoid possible ambiguities, the electrode potential thus defined can also
517:
This follows from the IUPAC definition of the electric potential difference of a galvanic cell, according to which the electric potential difference of a cell is the difference of the potentials of the electrodes on the right and the left of the galvanic cell. When
512:
446:
149:
367:. Proponents of the convention (2) argue that all reported electrode potentials should be consistent with the electrostatic sign of the relative potential difference.
158:
at the working electrode ("reversible potential"), or a potential with a non-zero net reaction on the working electrode but zero net current ("corrosion potential", "
226:
92:
In an electrochemical cell, the cathode and the anode have certain electrode potentials independently and the difference between them is the cell potential:
458:
17:
395:
669:
613:
609:
384:
642:
C.A. Hamel, "The
Encyclopedia of Electrochemistry", Reinhold Publishing Corporation, New York-Chapman & Hall Ltd., London, 1964, p. 429–431.
98:
310:. In both conventions, the standard hydrogen electrode is defined to have a potential of 0 V. Both conventions also agree on the sign of
196:
involves this reference electrode with hydrogen ion in an ideal solution having is "zero potential at all temperatures" equivalently to
181:
The value of the electrode potential under non-equilibrium depends on the nature and composition of the contacting phases, and on the
651:
P. van
Rysselberghe, "Bericht der Kommission für electrochemische Nomenklatur und Definitionen", Z. Electrochem., 58 (1954), 530–535.
581:
61:
The electrode potential has its origin in the potential difference developed at the interface between the electrode and the
712:
363:
switches sign when a reaction is written in reverse, so too, proponents of the convention (1) argue, should the sign of
246:
in the electrolyte, e.g., by positioning the reference electrode near the surface of the working electrode (e.g., see
389:
Potential of a cell assembled of two electrodes can be determined from the two individual electrode potentials using
197:
85:
due to the transfer of charged species across the interface, specific adsorption of ions at the interface, and
317:
The main difference between the two conventions is that upon reversing the direction of a half-cell reaction
660:
Anson, Fred C. "Common sources of confusion; Electrode Sign
Conventions," J. Chem. Educ., 1959, 36, p. 394.
576:
545:
171:
380:
58:. It may also be defined as the potential difference between the charged metallic rods and salt solution.
255:
193:
51:
186:
707:
155:
283:
182:
325:
also switches, whereas in the convention (2) it does not. The logic behind switching the sign of
586:
356:. It is assumed that the half-reaction is balanced by the appropriate SHE half-reaction. Since
251:
159:
528:
is positive, then positive electrical charge flows through the cell from the left electrode (
78:
290:
279:
376:
8:
262:
connected to the working electrode and the negative terminal to the reference electrode.
232:
50:
and another electrode to be characterized. By convention, the reference electrode is the
216:
The measurement is generally conducted using a three-electrode setup (see the drawing):
550:
163:
555:
385:
Electrolytic cell § Anode and cathode definitions depend on charge and discharge
330:
220:
679:
623:
686:
674:
627:
618:
507:{\displaystyle \Delta V_{\text{cell}}=E_{\text{red,cathode}}+E_{\text{oxy,anode}}.}
353:
247:
31:
441:{\displaystyle \Delta V_{\text{cell}}=E_{\text{red,cathode}}-E_{\text{red,anode}}}
239:
In case of non-zero net current on the electrode, it is essential to minimize the
192:
An operational assumption for determinations of the electrode potentials with the
591:
560:
294:
174:
for a given electroactive species by extrapolation of the measured values to the
162:"), or a potential with a non-zero net current on the working electrode (like in
270:
Historically, two conventions for sign for the electrode potential have formed:
275:
175:
258:. The potential measurements are performed with the positive terminal of the
701:
678:, 2nd ed. (the "Gold Book") (1997). Online corrected version: (2006–) "
622:, 2nd ed. (the "Gold Book") (1997). Online corrected version: (2006–) "
565:
370:
86:
43:
690:
631:
259:
240:
167:
82:
65:. It is common, for instance, to speak of the electrode potential of the
62:
208:
298:
47:
144:{\displaystyle E_{\text{cell}}=E_{\text{cathode}}-E_{\text{anode}}.}
570:
533:
243:
89:/orientation of polar molecules, including those of the solvent.
39:
529:
55:
314:
for a half-cell reaction when it is written as a reduction.
212:
Three-electrode setup for measurement of electrode potential
170:). Reversible potentials can be sometimes converted to the
371:
Potential difference of a cell assembled of two electrodes
329:
is to maintain the correct sign relationship with the
461:
398:
101:
27:
Electromotive force of a cell built of two electrodes
200:
of hydrogen ion is also "zero at all temperatures".
506:
440:
143:
54:(SHE). It is defined to have a potential of zero
699:
235:(standard hydrogen electrode or an equivalent).
321:, according to the convention (1) the sign of
154:The electrode potential may be either that at
72:
381:Electrochemical cell § Cell potential
348:is the number of electrons involved and
301:" (sometimes referred to as "European").
286:" (sometimes referred to as "American"),
207:
14:
700:
582:Table of standard electrode potentials
308:Gibbs–Stockholm electrode potential
265:
77:Electrode potential appears at the
24:
18:Electrochemical corrosion potential
680:electric potential difference, ΔV
675:Compendium of Chemical Terminology
636:
619:Compendium of Chemical Terminology
462:
399:
25:
724:
377:Galvanic cell § Cell voltage
46:built from a standard reference
183:kinetics of electrode reactions
663:
654:
645:
603:
203:
198:standard enthalpy of formation
13:
1:
597:
577:Standard electrode potential
546:Absolute electrode potential
172:standard electrode potential
7:
539:
194:standard hydrogen electrode
52:standard hydrogen electrode
10:
729:
713:Electrochemical potentials
532:) to the right electrode (
374:
81:between an electrode and
73:Origin and interpretation
691:10.1351/goldbook.E01934
632:10.1351/goldbook.E01956
624:electrode potential, E
587:Thermodynamic activity
508:
442:
252:supporting electrolyte
213:
187:Butler–Volmer equation
185:at the interface (see
145:
509:
448:however , it depends.
443:
254:of sufficiently high
211:
146:
571:Potential difference
459:
396:
99:
233:reference electrode
87:specific adsorption
36:electrode potential
682:of a galvanic cell
551:Electric potential
504:
452:or, equivalently,
438:
306:be referred to as
214:
164:galvanic corrosion
141:
556:Galvani potential
498:
485:
472:
435:
422:
409:
333:change, given by
331:Gibbs free energy
250:), or by using a
227:counter electrode
221:working electrode
135:
122:
109:
16:(Redirected from
720:
708:Electrochemistry
693:
667:
661:
658:
652:
649:
643:
640:
634:
607:
527:
513:
511:
510:
505:
500:
499:
496:
487:
486:
483:
474:
473:
470:
447:
445:
444:
439:
437:
436:
433:
424:
423:
420:
411:
410:
407:
366:
362:
354:Faraday constant
351:
347:
343:
328:
324:
313:
266:Sign conventions
248:Luggin capillary
150:
148:
147:
142:
137:
136:
133:
124:
123:
120:
111:
110:
107:
68:
32:electrochemistry
21:
728:
727:
723:
722:
721:
719:
718:
717:
698:
697:
696:
668:
664:
659:
655:
650:
646:
641:
637:
608:
604:
600:
592:Volta potential
561:Nernst equation
542:
526:
519:
495:
491:
482:
478:
469:
465:
460:
457:
456:
432:
428:
419:
415:
406:
402:
397:
394:
393:
387:
373:
364:
357:
349:
345:
334:
326:
322:
311:
268:
206:
160:mixed potential
132:
128:
119:
115:
106:
102:
100:
97:
96:
75:
66:
28:
23:
22:
15:
12:
11:
5:
726:
716:
715:
710:
695:
694:
662:
653:
644:
635:
601:
599:
596:
595:
594:
589:
584:
579:
574:
568:
563:
558:
553:
548:
541:
538:
524:
515:
514:
503:
494:
490:
481:
477:
468:
464:
450:
449:
431:
427:
418:
414:
405:
401:
372:
369:
303:
302:
287:
267:
264:
237:
236:
230:
224:
205:
202:
176:standard state
152:
151:
140:
131:
127:
118:
114:
105:
74:
71:
69:redox couple.
26:
9:
6:
4:
3:
2:
725:
714:
711:
709:
706:
705:
703:
692:
688:
684:
683:
677:
676:
671:
666:
657:
648:
639:
633:
629:
625:
621:
620:
615:
611:
606:
602:
593:
590:
588:
585:
583:
580:
578:
575:
572:
569:
567:
566:Overpotential
564:
562:
559:
557:
554:
552:
549:
547:
544:
543:
537:
535:
531:
523:
501:
492:
488:
479:
475:
466:
455:
454:
453:
429:
425:
416:
412:
403:
392:
391:
390:
386:
382:
378:
368:
361:
355:
342:
338:
332:
320:
315:
309:
300:
296:
292:
288:
285:
281:
277:
273:
272:
271:
263:
261:
257:
253:
249:
245:
242:
234:
231:
228:
225:
222:
219:
218:
217:
210:
201:
199:
195:
190:
188:
184:
179:
177:
173:
169:
165:
161:
157:
138:
129:
125:
116:
112:
103:
95:
94:
93:
90:
88:
84:
80:
70:
64:
59:
57:
53:
49:
45:
44:galvanic cell
41:
37:
33:
19:
681:
673:
665:
656:
647:
638:
617:
605:
521:
516:
451:
388:
359:
340:
336:
318:
316:
307:
304:
289:convention "
274:convention "
269:
260:electrometer
256:conductivity
238:
215:
191:
180:
153:
91:
76:
60:
35:
29:
484:red,cathode
421:red,cathode
204:Measurement
168:voltammetry
156:equilibrium
83:electrolyte
63:electrolyte
702:Categories
598:References
375:See also:
319:as written
573:(voltage)
497:oxy,anode
463:Δ
434:red,anode
426:−
400:Δ
299:Stockholm
126:−
79:interface
48:electrode
540:See also
534:cathode
352:is the
295:Ostwald
284:Latimer
244:IR-drop
121:cathode
40:voltage
38:is the
383:, and
344:where
276:Nernst
670:IUPAC
614:IUPAC
610:IUPAC
530:anode
291:Gibbs
280:Lewis
241:ohmic
134:anode
56:volts
42:of a
525:cell
471:cell
408:cell
108:cell
687:doi
685:".
628:doi
626:".
536:).
341:nFE
339:= –
189:).
166:or
67:M/M
30:In
704::
672:,
616:,
612:,
379:,
178:.
34:,
689::
630::
522:V
520:Δ
502:.
493:E
489:+
480:E
476:=
467:V
430:E
417:E
413:=
404:V
365:E
360:G
358:Δ
350:F
346:n
337:G
335:Δ
327:E
323:E
312:E
297:–
293:–
282:–
278:–
229:,
223:,
139:.
130:E
117:E
113:=
104:E
20:)
Text is available under the Creative Commons Attribution-ShareAlike License. Additional terms may apply.
