The discovery of the elements. XVII. The halogen family

THE DISCOVERY OF THE ELEMENTS. FAMILY*

XVII.

THE HALOGEN

The halogens were discmered in the order: chlorine, iodine, bromine, and fluorine. Although Scheele prepared chlorine in 1774 by the action of m n ganese d i o d e on hydrochloric acid, it was believed to be a compound until after 1810, when Sir Humphry Davy gave conwincing proof of its elementary nature. I n 1811 Bernard Courtois isolated iodine from the mother liquor obtained by leeching the ashes of marine algae. Balard's discovery of brominefifteen years later was a n especially important ment in the history of science, for chemists were just beginning to realize that there are family groups among the elements, and Dobereiner soon observed that chlorine, bromine, and iodine form a closely related triad. The long, dangerous search for fluorine, which brought suffering and death to senreral promising chemists, cnlminated successfully in 1886 through the brilliant efforts of Moissan.

Lo recherche d ' u n corps simple est toujours trds czptimnte ( I ) , (17). La science ne para& pas senlement avoir pour mission de satisfaire chez l'homme ce besoin de tout connattre, de tout apprendre, qui caractdrise la plus noble de nos facultBs; elle en a aussi une autre, m a n s brillante sans doute, mais peut-atre plus morale, je dirai presque plus sainte, qui consiste d colirdonner les forces de la nature pour angmenter la production et rapprocher les hommes de l'dgalitd par l'universalitd du &en-atre (2).

*

The bringing to light of the four halogens-chlorine, iodine, bromine, and fluorine-required a little more than a century. Although the first definite indication of the existence of chlorine was noted by Scheele in 1774, the isolation of fluorine by Moissan was not accomplished until 1886. Chlorine In his famous research on pyrolusite, Scheele allowed hydrochloric acid, or spiritus sulk as he called it, to stand in contact with finely ground pyrolusite (crude manganese dioxide), and noticed that the acid acquired thereby a suffocating odor like that of warm aqua regia, and "most oppressive to the lungs." He thought that the manganese dioxide had taken the combustible principle, phlogiston, from the hydrochloric acid, and tberefore called the gas "dephlogisticated marine acid," or "dephlogisticated muriatic acid." He noticed that it dissolved slightly in water, imparting to it an acid taste, that it bleached colored flowers and green leaves, and that i t attacked all metals (3).

* Illustrations collected by F. B. Dains of The University of Kansas 1915

1916

JOURNAL OF CHEMICAL EDUCATION

Novpm~n,1932

Lavoisier thought that all acids contain oxygen. Dr. William Henry, who obtained hydrogen by passing an electric discharge through gaseous "marine acid," concluded that it came from the water, and that water must be an essential constituent of hydrochloric acid (37), (38). Berthollet, who was a disciple of Lavoisier and not a phlogistonist, noticed that calcined pyrolnsite, which had lost some of the oxygen from its manganese dioxide, yielded less of the suffocating gas, "dephlogisticated marine acid," than could be obtained from an equal w e i ~ h tof fresh pyrolusite. He concluded that:.

British chemist and manufacturer, and author of books on chemistry. He discowed that. when a gas is absorbed in a liquid, the weight dissolved is ~rooortionalt o the Dressure of iheA gas (Henry's *law). He thought that water was an essential constituent of hydrochloric acid.

It is therefore to the vital air [oxygen] of the manganese [pyrolnsite], which combines with the marine acid, that the formation of the dephlogisticated marine acid is due. I ought to state that this theory was presented and announced some time ago by M. Lavoisier, and that M. de Fourcroy made use of i t in his "Elements of Chemistry and Natural History" to explain the properties of dephlogisticated marine acid such a s t h e y were t h e n known.

TITLE PAGEOR WILL= HENRY'S"EPITOME oa CEEMISTRY" I n the original Benjamin Silliman's autograph can be seen just above the words "Professor of Chemisw."

VOL.9, NO. 11 THE DISCOVERY OF THE ELEMENTS. XVII

1917

Berthollet thought that the gas now known as chlorine was a loose compound of hydrochloric acid and oxygen, or, to use his own words, that: [Dephlogisticated marine acid] is manifestly formed by the combination of vital air with marine acid, but in it the vital air is deprived of a part of the prinaple of elasticity, and adheres so feebly to the marine acid that the action of light suffices to disengage it promptly, light having more affinitv for its base than marine acid has (1). ,. In the year IS07 Sir Humphry I)a\-y obtained hydrogen by the action of ootassimn on "muriatic acid," and concluded that i t must have come from the water in the acid, and that the oxygen in the water must have converted the potassium to potassium

..

BERTROLLET. 1748-1822 French chemjst and physician. Professor at the Ecole Normale. He collaborated with Lavoisier in his researches and in reforming chemical nomenclature. Berthollet'i "Essai de statique chimique"emphasized the importance of the relative masses of the reactine suhstances in chemical reactions. COUNT

C ~ ~ u oLOUIS e

-

SIRHUMPHRY DAW 1778-1829

British chemist who isolated the alkali and alkaline earth metals and boron, and proved that chlorine is an element. Gay-Lussac and Thenard isolated boron independently at about the same time.

oxide (5). Gay-Lussac and Thenard, however, did not accept this exolanation. They that the . armed hydrogen came neither from the acid nor from the water, but from the potassium, which was t h e r e u p o n changed back into caustic potash, which then reacted with the acid. They tested the "oxidized marine acid" (chlorine) with glowing charcoal, but, since they could detect no oxygen, they concluded that oxygen was famed only in the presence of water. ,411their attempts to decompose the chlorine by heating it with dry charcoal proved fruitless (6).

1918


NOVEMBER, 1932

Gay-Lussac and Thenard believed (1) that muriatic gas contains onefourth of its weight of water, (2) that oxymuriatic gas is a compound of oxygen and some other substance, and (3) that the substance obtained by heating calomel with phosphorus is a triple compound consisting of dry muriatic acid, oxygen, and phosphorus. Davy's final views on these three points were as follows: (1) muriatic acid is composed of oxymuriatic acid (chlorine) and hydrogen, (2) chlorine is an element, and (3) the substance obtained by heating calomel with phosphorus is a compound of the elements chlorine and phosphorus (7). Since Berthollet, Gay-Lussac, Thenard, Fourcroy, and Chaptal all belonged to the French school founded by the illustrious Lavoisier, it was difficult for them to admit the existence of an acid that contained no oxygen, but nevertheless they soon had to yield to the convincing evidence presented by Sir Humphry (S), (41). Dr. John Murray in Edinburgh and Berzelius in Stockholm continued, for some time to regard ; however, chlorine as a compound. After iodine was discovered in 1811, the evidence for the elemen' tary nature of chlorine became still more convincing, and by 1820 even Berzelius had yielded (9). When Anna, his cook, remarked one day that the flask she was washing smelled of "oxidized muriatic acid," Berzelius replied, "Anna, you mustn't speak of oxidized muriatic acid any JONS JACOB BERZELI~S,* 1779-1848 more; from now on you must say He was one of the last chemical chlorine" (10). authorities to be convinced of the eleThe discovery of bromine by Balmentary nature of chlorine. ard and the preparation of prussic (hydrocyanic) acid, an oxygen-free acid, by Gay-Lussac made the evidence conclusive. Davy's formal announcement of the elementary nature of chlorine was made in a memoir which he read before the Royal Society on November 15, 1810 (8). Sir Humphry Davy's life was a short one, and his last years were marred by continued illness. In a letter written in Rome in February, 1829, he

* Reproduced from H. G. SBderbaum's "Jac. Berzelius Levnadsteckning" by kind permission of Dr. SOderbaum.

VOL. 9. No. 11 THE DISCOVERY OF THE ELEMENTS. X V I I

said, "If I die, I hope that I have done my duty and that my life has not been vain and useless" (50). Three weeks later he was stricken with palsy, from which he never recovered. Even the devotion and medical skill of his younger brother, Dr. John Davy, were in vain. When spring came Dr. Davy thought it best t o take his brother from Rome to Geneva in order to avoid the hot Italian summer. The long journey by horse and carriage was most exhausting, and Sir Humphry died a t Geneva on May 29, 1829. His desire that his life might be useful was so richly fulfilled that his name will always be honored as that of a supremely great scientist and humanitarian.

Iodine?

ANNA

lUlY

SUNDSTROM.* BEREELIUS'

HOUSEKEEPER She kept house for him for many years before he was married and prepared the meals in the kitchenlaboratory, where his sand-bath on the stove was never allowed to cool. Berzelius once said that he could not h a k thus entrusted the management of his home t o any other person of the servant clas.

Iodine, one of the most beautiful of all the elements, was first observed in 1811 by Bernard Courtois, who was born on February 8, 1777, in a house just across the street from the famous old Dijon Academy. His father, Jean Baptiste Courtois, was a saltpeter manufacturer who used to assist Guyton de Morveau, the lawyer, in his brilliant lectures on chemistry. Thus the son lived constantly in a chemical environment, dividing his time between the paternal saltpeter works and the laboratories of the Academy. After Citizen Guyton was called to the Legislative Assembly in 1791, J. B. Courtois gave up his position a t the Academy in order to devote all his time to the manufacture of niter. After assisting his father for a time, Bernard was apprenticed for three years t o a pharmacist a t Auxerre, M. Fremy, the grandfather of Edmond Fremy, the famous chemist. In

* Reproduced from H. G. Siiderbaum's "Jac. Berzeliur Levnadsteckning" by kind permission of Dr. Siiderbaum. t The pictures of the Dijon Academy, the scaled tube containing the first iodine, and the Courtois autograph letter have been reproduced by courtesy of Dr. L. G. Toraude from his book. "Bernard Courtois et la DCcouverte de I'Iode." The autograph letter belongs to the departmental archives of the CAte d'Or. The photograph of the sealed tube was taken a t Dijon on Nov. 9. 1913, the day of the ceremony in honor of the one hundredth anniversary of the discovery of iodine.

1920


From l'oraude'r " B r r r o r d Corcrloii al

NOVEMBER. 1932

lo DIcouverie d p i ' l o d r ' '

THEOLD DIJONACADEMY(B) AND THE B ~ T H P L A C(E) E OF BERNARDCOURTOIS (PRESENT CONDIT~ON OF THE BUILDINGS) In the middle of the nineteenth century the latter building was enlarged and made higher. The street at C is the Rue Monge (formerly Rue du P o d A m a d d ) . When it was widened, the quarters in the Academy Building formerly occupied by Bernard's father, Jean-Baptiste Courtois, assistant to Guyton de Morveau, were torn down. the meantime Guyton de Morveau had @come the director of the Bcole Polytechnique, and through his intervention Bernard Courtois was admitted to the laboratories of this school to study under Fourcroy. Here he entered into his research and courses in p u e chemistry with pleasure and enthusiasm. I n 1799, however, he was called to serve his country as a pharmacist in the military hospitals. In 1804, while serving as prdparateur under Seguin, he made an important investigation of opium (51). Although J. B. Courtois failed in business, he was an honest man, and both father and son struggled hard to pay their creditors. In 1808 Bernard Conrtois married Madeleine Eulalie Morand, a young girl of humble parentage who could barely read and write. Along the coasts of Normandy and Brittany many plants live a t shallow depth in the ocean, and some of them are cast ashore by the waves and tides. For plants such as these the French writers of the early nineteenth century used the term warech,* from which the English words wrack and wreck have been derived (13). By burning Fucus, Laminaria, and other brown algae gathered a t low tide, and by extracting the ash with water, * The word varech is at present applied only to cabin marine phanerogams used for packing and upholstering.

V ~ L9,. No. 11 THE DISCOVERY OF THE ELEMENTS. XVII

1921

"Bnnard Caurfois el lo DEcouverlE dc 1'Iodr"

AWOGRAFTI oa BERNARDCounrors (1794) Translation: "I have received fram D'orgeu township 50 casks of saltpeter solution which they have drawn fram their property and which they have asked me to take because they have no one sufficiently trained to extract the saltpeter from it. Dijon the 11th of Messidor, the 2nd year of the Republic, one and indivisible. B. Courtois. son. .". He was seventeen years old when he wrote this receipt.

.

C

Courtois obtained some mother liquors known as salin de oarech, or soude de varech. The algae that Courtois used yield an ash containing chlorides, bromides, iodides, carbonates, and sulfates of sodium, potassium, magnesium, and calcium. In his day, however, they were valued merely for their sodium and potassium compounds, which were recovered by burning the dried algae in longitudinal ditches along the seashore and leaching the ashes a t the works. As evaporation proceeded, sodium chloride began to precipitate, and later potassium chloride and potassium sulfate. The mother liquor then contained the iodides of sodium and potassium, part of the sodium chloride, sodium sulfate, sodium carbonate, cyanides, polysulfides, and some sulfites and hyposulfites resulting from the reduction of sulfates during calcination. To destroy these sulfur compounds Courtois added sulfuric acid, and on one eventful day in 1811 he must have added it in excess (54). To his astonishment lovely clouds of violet vapor arose, and an irritating odor like that of chlorine permeated the room. When the vapors condensed on cold objects, no liquid was formed, but there appeared instead a quantity

1 612"


t,>fcj2,x,t,

,I# ,.I,,, t,..

SEALED TUBE CONTAINLNI: IODINE

ISOLATED BI. COURTOISPROM THE MOTHERLIQUORSPROM THE PREPARATION OF SALTPETRR This tube, belonging t o the Salvay campany of Belgium, was presented a t the iodinc centenary (Nov. 9, 1913) throuah the courtem of M C. Crinon.

NOVEMBER, 1932

of dark crystals with a luster surprisingly like that of a metal (45). Courtois noticed that the new suhstance did not readily form compounds with oxygen or with carbon, that it was not decomposed a t red heat, and that it combined with hydrogen and with phosphorus. He observed that it combined directly with certain metals without effervrscence and that it formed an explosive compound with ammonia. Although thesc striking properties made him suspect the presence of a new element, he was too lacking in self-confidence t o attempt a thorough investigation in his poorly equipped laboratory and too poor to take the time from his business (11). H e therefore asked two of his Dijon friends, Chades Bernard Desormes and Nicolas Clement, Desormes' fnture son-in-law, t o continue his researches in their laboratory a t the Comematoire des arts et des mitiers, and allowed them t o announce the discovery to the scientific world (451, (55). Courtois was engaged for some years in the manufacture of iodine compounds and other chemical reagents, but in 1835 he was obliged to give up his business and go about the city taking orders. ~ i c o r d i nt~o Fremy, he prepared very pure iodine, gave specimens of it to his chemical friends. and noted its action on organic substances. Fremy also said:

Thev have been uniust to Courtois in keating him a& simple saltpeter-maker; he was a very skilful chemist (un chimiste trPs hahile) : he ought t o have been rewarded for his discovery of iodine, and not left to die in poverty (12), (13).

Vor.. 9,

No.

11 THE DISCOVERY OF THE ELEM13NTS. XVII

1923

Courtois died in Paris on September 27, 1838. The Montyon prize of six thousand francs which the Royal Academy had awarded him in 1831 "for having improved the art of healing" had all been spent, and the widow, poor and uneducated, struggled against approaching deafness and blindness in a vain attempt to earn her living by lacemaking. It is indeed sad to know that her last months were spent in a charitable institution. In the anditorium of thc niion ;Lademy, harmoniously decorated in the style of Louis XIV, there occurred on November 9, 191:j.* a solJ X A N A N ~ , ~ Cr.,~tmrc I $ CHAPIAT., C o m . ulr ~ CHAW~IILOUP, 1731; IX:?' emn civic ceremony in honor of the French physician, chemist, and manuone hundredth anniversary of the facturer of saltpeter. soda, and beet discovery of iodine. At that time a sugar. Minister of the Interior under Napoleon. Author of bookson chemical commemorative plaque was placed industry. on the birth~laceof Courtois, and in the following year a street was named for him. While Desormes devoted most of his time'to applied chemistry, Clement (1779-1841) carried out a classical research in h i c h he prepared the new substance and made a thorough study of its properties. In his report in 1813 he wrote: The mother liquor from seaweed ash contains quite a large quantity of a very peculiar and curious substance; it is easily extracted; one merely pours sulfuric acid on the mother liquor and heats the mixture in a retort the mouth of which is connected to a delivery-tube leading to a bulb. The substance which is precipitated in the form of a black, shining powder immediately after the addition of sulfuric acid, rises, when heated, in vapor of a superb violet color. This vapor condenses in the delivery-tube and receiver in the form of very brilliant crystalline plates having a luster equal to that of crystalline lead sulfide. Upon washing these plates with a little distilled water, one obtains the substance in the pure state ( 4 5 ) , (13). Clement believed iodine to be an element similar to chlorine (12), and showed it, first to Chaptal and AmpPre, and later to Sir Humphry Davy. *Although Courtois discovered iodine in 1811, the announcement by Clement and Desormes was not made until two years later. Therefore the centenary was obsrrved in 1913.

1924


NOYBMREH. 1932

The proof of its elemetllary naturc was given independently by Davy in England a n d by Gay-Lussac in France. Davy showed that iodine vapor is not decomposed by a carbon filament heated red-hot by a voltaic current (12), (46). In his classical research, the results of which were published in 1814, Gay-Lussac prepared hydrogen iodide and showed that i t reacts with mercury, zinc, and potassium to give the corresponding metallic iodides, hydrogen, and no other product ( 5 ) , (39). In 1820 Dr. Coindet of Geneva introduced the use of iodine in the treatment of goiter (13), (56). Long before this, however, i t had been unknowingly used for this purpose in the form of ash from sponges. Prolessor of chemistry at HeidelBromine berg. Zurich, and Breslau. He pre~ a r e dbromine in 1825. but before his In 1825 Carl Lowie. a new student investigation was completed Balard , had announced the discovery. %wig who had just entered the chemical discovered bromine hydrate, bromal iab8rat0ry at Heidelberg, the hydrate, and bromoform, and was the founder of the Silesian chemical inimmediate interest of Leopold Gmelin, dustry and of the Goldschmieden his professor. Lowig had brought alumina works at Deutseh-Lissa.

-.

with him from his home a t Kreuznach a red liquid which he had prepared by passing chlorine into the mother liquor from a salt spring and shaking it out with ether. The red liquid had remained after he had distilled off the ether. Professor Gmelin asked him to prepare more of it in order to study its properties, but in the meantime there appeared in 1826 in the Annales de chimie et de physique a paper by Balard announcing the discovery of bromine (28), (36), (57). The properties which Balard ascribed to bromine were identical with those Lowig had observed for the substance from Kreuznach. This explains why Balard, instead of Lowig, is regarded as the discoverer of bromine. Carl Lowig was born a t Kreuznach on March 17, 1803. In his youth he studied pharmacy, but his later study was confined entirely to chemistry.

* The author is deeply grateful to Dr. M m Speter of Berlin and Dr. Julius Meyer of Breslau for their assistance in obtaining this portrait, the original of which hangs in the Chemical Institute at Breslau. Some valuable information about Liiwig's scientific activities was also graciously contributed by Professor Meyer.

VOL.9, No. 11 T H E DISCOVERY OF T H E ELEMENTS. XVII

la5

1926

JOURNAL

017

CHIIMICAI. B1)UCATION

N o v ~ ~ n t i 1932 n,

He continued his investigation of the compounds of hromine for several years, 'and in 1820 published a monograph on "Bromine and Its Chemical Relations." In 1833 he was called to the newly founded University of Zurich, where, in spite of the very meager equipment, he analyzed many Swiss mineral waters and published monographs on them. His "Chemie der orcanischen Verbindungen," based on the radical theory, "was the Beilstein of that time, and was to he found in the hands of every chemist" (57). I n 1853 Lowig became Bunsen's successor a t Breslau. He was given offices of great responsibility, and served as Rector both a t Zurich and a t Breslau. He taught six semesters a t Heidelberg, forty a t Zurich, and seventy-two a t Breslan, and hoped to teach two more in order to make the total one hundred and twenty. This hope was not to be realized, however, for, while walking in the zoological garden, he failed to notice some steps, fell, and received a fracture of the hip from which he never recovered. He died on March 27, 1890, ten days after his eighty-seventh birthday (57). Antoine JkrBme Balard (or Ballard) ( 1 4 ) , was horn a t Montpellier on September 30, 1802. Since his parents were poor, he was adopted and educated by his godmother. He studied at the College of Montpellier for a time, and a t the age of seventeen years he became a prbfarateur a t the &ole de Pharmacie, where he graduated in 1826 (47). In 1824, while studying the flora of a salt marsh, he noticed a deposit of sodium sulfate which had crystallized out in a pan containing mother liquor from common salt. I n an attempt to find a use for these waste liquors he performed a number of experiments, andnoticed that when certain reagents were added, the mother liquor became brown. His investigation of this phenomenon, made when he was only twenty-three years old, led to the remarkable discovery which Dulong described in the following letter t o Berzelins written on July 1. 1826: . . .But here is another piece of recent news. . . It is a new simple body which will find its place between chlorine and iodine. The author of this discovery is M. Ballard of Montpellier. This new body, which he calls muride, is found in sea water. He has extracted it from the mother liquor of Montpellier brines by saturating them with chlorine and distilling. He obtains a dark red liquid substance boiling a t 47". The vapor resembles that of nitrous acid. Its specific gravity is 3. One preserves i t under concentrated sulfuric acid. It combines with metals and gives compounds sensibly neutral, of which several are volatile, notably the muride of potassium. . . (15). Since the name muride did not find favor with the French Academy's committee, consisting of Vauquelin, Thenard, and Gay-Lussac, the element is now known as bromine, meaning bad odor (121, (26). When Balard 'made this eventful discovery, he was merely an obscure young assistant in the chemistry department of his college. He had noticed

VOL.9, NO.11 THE DISCOVERY OF THE ELEMENTS. XVII

1927

Balard, the discoverer of bromine, Moissan, the discoverer of fluorine, Lamy who isolated thallium, and M. and Mme. Cori?, the discoverers of radium, all taught at the Sorbonne.

that when the lye from the ash of Ft~cuswas treated with chlorine water and starch, two layers appeared in the solution. The lower layer was blue because of the action of the starch on the iodine, and the upper one E was intensely yellow. The young assistant concluded that there were only two possible explanations: The yellow substance must either be a compound of chlorine with some constituent of the lye, or it must be a new element just liberated from one of its compounds by the chlorine, which had replaced it. Balard a t first favored the first hypothesis and thought that he had an iodide of chlorine, but, when all attempts to decompose the new substance failed, he concluded that his second explanation must be the correct one and that the new element must be similar to iodine and chlorine (28). He afterward found that bromine can be shaken out of solution, first with ether and then with caustic potash. Upon heating the resulting potassium bromide with sulfuric acid and manganese dioxide, the bromine can be distilled off and condensed as a red liquid or collected in water (12). Just as mercury is the only metal whose liquid phase is stable at room temperature, bromine is the only liquid non-metal. The French Academy's report of the Procbverbal of Monday, August 14, 1826, signed by Vauquelin, Thenard, and Gay-Lussac, reads as follows:

If the few experiments which we have been able to perform have not afforded us that certainty of the existence of bromine as a very simple

1928


NOVEMBER, 1932

body which in the present day is properly required, we consider it a t least very probable that it is so. The memoir of M. Balard is extremely well drawn up, and the numerous results which he relates would not fail to excite great interest, even if it should be proved that bromine is not a simple body. The discovery of bromine is a very important acquisition to chemistry, and gives M. Balard honorable rank in the career of the sciences. We are of the opinion that this young chemist is every way worthy of the encouragement of the Academy, and we have the honor to propose that his memoir shall be printed in the Receuil des Savants gtrangers (If?), (29). In 1842 Balard succeeded Thenard a t the Sorbonne, and in 1851 he accepted a professorship a t the CollPge de France (36). He discovered hypochlorous acid, worked out the constitution of JaveIle water (44), and perfected industrial methods for the extraction of various salts from sea water. He worked for twenty years a t these technical researches, and extracted sodium sulfate, the basis of the soda industry, directly from sea water. He also extracted potassium salts from the sea water, and his artificial potash, entering into cbmpetition with that from the ashes from plants, soon lowered the price. Before the discovery of the Stassfurt deposits in 1858, all the bromine used by photographers was prepared by Balard's method. The memory of his early poverty made Balard economical in his researches and ascetic in his manner of living. Although he survived his three children and his wife, his stepchildren were a great consolation to him in his old age. He died in 1876, honored because of his achievements and loved because of his generosity, d d e s t y , and warmth of heart (47). The glory due to Balard for his discovery of bromine is enhanced when one knows that the great Liebig just missed it. Several years before, a German firm had asked Liebig to examine the contents of a certain bottle, and he had concluded, without thorough study, that the substance was iodine chloride. When he heard of the discovery of bromine, he immediately recognized his error and placed the bottle in a special case which he called his "cupboard of mistakes" (11). Hence, when his dear friend Wohler a few years later just missed discovering vanadium,* Liebig knew how to sympathize with him. As soon as he had read Balard's paper on bromine, Liebig examined the brine from Theodorshalle near Kreuznach and prepared nearly twenty grams of bromine. His experiments led him to conclude, as Balard had done, that it must be a simple substance (27). Fluorine The history of fluorine is a tragic record. Marggraf described hydrofluoric acid in 1768, and Scheele studied i t three years later. Lavoisier, i t

* See Part VII.

VOL.9. NO. 11 THE DISCOVERY OF THE ELEMENTS. XVII

1929

will be recalled, thought that all acids contain oxygen, but Davy showed that this one does not. Ampere suggested to Davy that hydrofluoric acid must be a compound of hydrogen and an unknown element (31), (32). Paul Schutzenherger expressed the belief that this unknown substance, fluorine, would be found to be the most active of all the elements, and correctly predicted some of its properties ( I S ) , (19). It is this extreme activity of the element that made its liberation such a difficult and dangerous task and brought agony and death to some of the pioneer investigators. Davy, Gay-Lussac, and Thenard all suffered intensely from the effects of inhaling small quantities of hydrogen fluoride vapor. Davy found that his silver and platinum containers were attacked, but believed that fluorine could be liberated if a fluorspar vessel were used (23), (30). Two members of the Royal Irish Academy, George Knox and his brother, the Reverend Thomas Knox, of Toomavara, Tipperary, made an ingenious apparatus of fluorspar. They were unable, however, to liberate the halozen. and both suffered the frightful -torture of hydrofluoric acid poisoning (20). The Reverend Thomas Knox nearly lost his life, and George Knox had to rest in Naples for three years in order to A~oni.-hI.%nrr,AMFARE regain his health (48). P. Louyet of 1775-183fi Brussels, although fully aware of Frenchphysicist, mathemafician, and Professor at the Ecole Polythe cox brothers' misfortune, con- chemist. technique, Paris. One of the founders tinued his dangerous researches too of electrodynamicr. Inventor of the to science astatic needle. The practical unit of long, and d i e d ~a current strength was named for him.

(17), . (.I S .) , (40), . . (42). . . Professor TB r8me NicklPs of Nancy met a similar fate (35), (43), (60). Edmond Fremy, who had watched Louyet perform some of his experiments (33),tried to decompose anhydrous calcium fluoride electrolytically, and did obtain calcium a t the cathode, while a gas, which must have been fluorine, escaped a t the anode (34). However, because of its tendency to add on to other substancesand form ternary and quaternary compounds, Fremy failed in all his attempts to collect and identify the gas. When he allowed chlorine to act on a fluoride, he obtained no fluorine, but only a fluochloride; when he used oxygen in place of chlorine, he obtained an oxyfluoride.

1930


NOVEMBER. 1932

This seemingly hopeless field of experimentation was soon abandoned, but in IS69 the English chemist, George Gore, liberated a little fluorine, which immediately combined explosively with hydrogen ( l a ) , (35). When he tried to electrolyze anhydrous hydrofluoric acid "with anodes of gas-carbon, carbon of APPARATUSUSED BY THE KNOXBROTHERSI N THEIR lignum-vitae, and of ATTEMPTSTO LIBERATE FLUORINE many other kinds of Upon treating dry "fluoride of mercury" with dry wood, of p a l l a d i u m , chlorine they obtained crystals of mercuric chloride. platinum, and gold,. . A piece of gold foil which had been acted on by the gas in the receiver was placed on glass and treated the gas-carbon disinwith sulfuric acid. Since the glass was attacked, they tegrated rapidly, all the concluded that fluorine had been liberated and had formed gold fluoride. No hydrogen was detected. kinds of charcoal flew to Vig. 1 . Fluorspar vessel in the stand which holds pieces quickly, and the down thc receiver by means of spiral springs. Pig. 2. Vessel with cover off.showing thc orificc anodes of palladium, and the small deprrssions containing gokl leal. platinum, and gold were Ipig. 3. Kecewrr. Fig. 4. Stopper. +, corroded without evolution of gas" (3.7). Moissan mentioned the "remarkable exactitude" of Gore's memoir (23). The apparently impossible task was finally accomplished by Moissan in 1886. Ferdinand Frediric Henri Moissan was born a t 5 , Rue Montholon in Paris on September 28, 1852. When he was twelve years old, the family moved to the little town of Meau in the department of Seine-et-Marne. where he attended the municipal college. His first lessons in chemistry were received from his father, a railroad official (22), (58). Obliged to leave school a t the age of eighteen years, he became an apprentice in the Bandry apothecary shop located a t the intersection of Rue Pernelle and Rue Saint Denis in Paris. Here his ready knowledge of chemistry enabled him to save the life of a man who had swallowed arsenic in an attempt a t suicide (21), (22). In 1872 Moissan decided to give up his position a t the pharmacy in order to study under Edmond Fremy a t the MnsCe d'Histoire Naturelle. Here he not only made rapid progress in chemistry and pharmacy, but also became a connoisseur of art and literature, and even wrote a rhymed play which was almost accepted for the audiences at the OdCon. He was afterward able to laugh a t this early disappointment

VOL.9, No. 11 T H E DISCOVERY OF T H E ELEMENTS. XVII

1831

and to say, "I believe I did better to become a chemistn* (22). In 1879 he passed his examination for firstclass pharmacist and accepted a position a t the ficole SupQieure de Pharmacie (21), (58). Three years later there occurred in Moissan's life a most f o r t u n a t e event- his marriage to Leonie Lugan. She proved to be a devoted wife and comrade, a hospitable, charming hostess, and a great help to him in his scientific work. M. Lugan was also an ideal father-in-law, in full sympathy with Moissan's scientific

Professor of chemistry a t the heole Polytechnique and director of tnc Museum d'Histoire Naturelle. He prepared anhydrous hydrogen fluoride hut was unable to liberate the fluorin?. He was present, however, when hi4 former pupil. Henri Moissan, crhihited the new gas before a committer from the Academy of Sciences. Fremy wrote a monograph on the synthesis of rubies. See J. CHEM. EDUC., 8, 1017-9 (June, 1931) for illustrations of his artificial rubies.

DR. G ~ o n c i i G1mrr.1 1826-1908 English rlcctrochc~nist. Head of the Institute of Scientific Research, Easy Row, Birmingham. He improved the art of electroplating and wrote treatises on "The Art of Electrometallurgy" and "Thc Electrolytic Separation and Refining of Metals." His estate was bequeathed to the Royal Society of London and the Royal Institution of Great Britain.

researches. He gladly provided material support for his daughter's family, and urged Moissan to devote all his time to science, unhampered by financial worries. Since the latter had no laboratory at the School of Pharmacy, he did his first experimental work in a building situated on the Rue Lancry, but Debray afterward allowed him to use the more powerful battery in a temporary barracks on the Rue Michelet (22).

~-

p~~

* "Je

crois que j'ai mieux fait rle faire de la chimic."

t This portrait was obtained through the courtesy of Mr. R. B. Pilcher, Registrar and Secretary of the Institute of Chemistry of Great Britain and Ireland.

1932


N o v ~ m ~1932 n,

Fremy had concluded from his experiments that fluorine had probably been liberated in the electrolysis of the fluorides of calcium, potassium, and silver, but that, because the temperature f a d been too high, it had immediately attacked the container. He prepared anhydrous hydrogen fluoride, but found himself caught in the horns of the following dilemma: when moist hydrogen fluoride was electrolyzed, he obtained only hydrogen, oxygen, and ozone; and dry hydrogen fluoride would not conduct the current (22). Moissan reasoned that if he were trying to liberate chlorine he would not choose a stable solid like sodium chloride, but a volatile compound like hydrochloric acid or phosphorus pentachloride. His preliminary experiments with silicon fluoride convinced him that this was a very stable compound, and that, if he should ever succeed in isolating fluorine, it would unite with silicon with incandescence, and that therefore he might use silicon in testing for the new halogen. After many unsuccessful attempts to electrolyze phosphorus trifluoride and arsenic trifluoride, and after four interruptions caused by serious poisoning, he finally obtained powdered arsenic a t the cathode and some gas bubbles a t the anode. However,

* The picture OF Moissan preparing fluorine has been reproduced from an article by GASTON TISSANDIRR,L~ Nature, 18 [I], 177 (Feb. 22, 1890),by permission of Masson et Cie. kditeurs, Paris.

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XVII

F m c h chemist and historian of chemistry. His researches were in the diverse fields of organic synthesis, chemical statics and dynamics, thermochemistry, explosives, nitrifying bacteria in the soil, and the oriental sources of alchemy. I n his early days he assisted Balard a t the College de France and many years later he served on a committee with Debray and Fremy t o investigate Moisran's discovery of fluorine.

1933

1934


NOVEMBER, 1932

before these fluorine bubbles could reach the surface, they were absorbed by the arsenic trifluoride to form the pentafluoride ( l a ) , (23). Moissan finally used as electrolyte a solution of dry potassium acid fluoride in anhydrous hydrofluoric acid. ,His apparatus consisted of two platinum-iridium electrodes sealed into a platinum U-tube closed with fluorspar screw caps covered with a layer of gum l& (42), (49). The U-tube was chilled with methyl chloride, the gas now used in many modern refrigerators, to a temperature of -23'. Success finally came. On June 26, 1886, a gas appeared a t the anode, and when he tested it with silicon, it immediately burst into flame. Two days later he made the following conservative announcement to the Academy: One can indeed make various hypotheses on the nature of the liberated gas; the simplest would be that we are in the presence of fluorine, but it would be possible, of course, that it might be a perfluoride of hydrogen or even a mixture of hydrofluoric acid and ozone sufficientlyactive to explain such vigorous action as this gas exerts on crystalline silicon (42). This announcement was read to the Academy by Debray, for Moissan was not then a member, and the president appointed a committee consisting of MM. Debray, Berthelot, and Fremy to investigate the discovery. In the presence of these distinguished guests, the apparatus acted like a spoiled child. Moissan could not obtain as much as a bubble of fluorine.

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1935

However, on the following day he used fresh materials and demonstrated his discovery to the entire satisfaction of the committee (22). Thus Fremy, who had come so near to making this discovery himself, was able to say with all sincerity, "A professor is always happy when he sees one of his students proceed farther and higher thanhimself" (60). The successful isolation of fluorine made M o i s s a n ' s n a m e known throughout the scientific world, and in 18113 another achievement won for him more popular publicity than he desired. On February sixth of that year he succeeded in preparing small artificial diamonds by suhiectinr suzar ., charcoal to enormous pressure (2),(53), (63). ALFREDIS. S T O C K Director of the Chemical Institute Most of his diamonds were of the Technische Hochschule of Karlslike carhonado, but the largest one, mhe. Former student of Henri Moissan 0.7 of a millimeter long, was color. and author of an excellent biographical sketch of the latter. Visiting lecturer a t less. His collea~uesaffectionately Cornell University in 1932. He is an this little diamond " T ~authoritrp ~ on the-high-vacuum method for studying volatile substances, the Regent," for to them i t was as chemistry of boron, the preparation and precious as the 137-carat specimen properties of beryllium, and chronic mercurial poisoning. in the Louvre (22). Moissan's electric furnace was a valuable incentive to research. With its aid he prepared many uncommon metals such as uranium, tungsten, vanadium, chromium, manganese, titanium, molybdenum, columbium, tantalum, and thorium, much of this work being done a t the Edison Works on Avenue Trudaine (24). As a practical result of her husband's researches, Mme. Moissan was one of the first women in the world to use aluminum cooking utensils (22). Moissan always insisted on extreme neatness in his laboratory, and the wooden floors were waxed every Saturday. Alfred Stock (64) relates that one day Professor Moissan looked critically a t the floor and said reproachfully, "Who did that?" Upon careful examination, Dr. Stock noticed that a few drops of water from the tip of his wash-bottle had fallen to the polished floor (22). Moissan was one of the most polished scientific lecturers in Paris. His ease of delivery, his well-modulated voice, his carefully chosen experiments,

JOURNAL OF CHEMICAL ICUUCATION

1936

N ~ l v a ~ e 1932 ~n,

and his gentle humor attracted great crowds to his lectures a t the Sorbonne. At exactly five o'clock the two large doors of the lecture-room used to be opened simultaneously by two servants, and a t a quarter past five the lecture began. Then for an hour and a quarter Moissan held the eager attention of his audience. Sir William Ramsay said of him, His command of language was admirable; i t was French a t its best. The charm of his personality and his evident joy in exposition gave keen pleasure to his auditors. He will live long in the memories of all who were ~rivileeedto know him, as a man full of human kindness. of tact, and of true love for the subject which he adorned by his &: life and work (22), (48). #I)

Moissan had - an artistic. hosdtable home in the quiet Rue Vauquelin, and was proud of his Corot landscape and his fine collection of autographs. M. and Mme. Moissan . . and their son Louis usually spent their vacations traveling in Italy, Spain, Greece, the Alps, or the Pyrenees, and in 1904 Moissan came to America to visit the St. Louis World's Fair (22). HisJife was undoubtedly shortened 7 by his continued work with the toxic -cases.. fluorine and carbon monoxide. Hrirm ~ ~ O I S S A N He died on February 20, 1907. His 1852-1007 only child, Louis, an assistant a t the Professor of el~emistryat the Ecole de phamacie, who was killed SupCrieurc de Phannacie. The disOn a battlefield of the World War, coverer of the element fluorine. With his electric furnace he prepared many left 200,000 francs to the school for uncommon metals such a3 uranium, the establishment of two prizes: the tungsten, and vanadium. Moissan chemistry prize in memory of his father and the Lugan pharmacy prize in honor of his mother (25), (65). Literature Cited

I, ,

( 1 ) MorssaN, "Le Fluor et ses CornposCs," Steinheil. Paris, 1900, preface, p. viii.

"L'~v01utionde la Chimie au XIXBSiPcle," BibliothPque Larousse, ( 2 ) OSWALD. Paris, 1913, p. 26, Quotation from Balard. (3) Alembic Reprint No. 13, "The Early History of Chlorine," University of Chicago Press, Chicago, 1902, pp. 8-9; SCREELE,"On Manganese and Its Properties." (4) Ibid., p. 20. BERTHOLLET, "Memoir on Dephlogisticated Marine Acid," Memoires de 1'Acadtmie Royale. 1785, Paris. 1788, pp. 27595.

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1937

l?Knssn, "Geschichtliche Entwicklung der Chemic," Springer, Berlin, 1921, pp. 119-22. AND THENARD, Alembic Reprint No. 13, Ref. (3). pp. 3748. GAY-LUSSAC "On the Nature and Properties of Muriatic Acid and of Oxygenated Muriatic Acid." Ibid., p. 49. GAY-LUSSAC n m THENARD. "Extract from 'Rechaches PhysicoChimiques.' " Val. 2, Imprimerie de Crapelet, Paris. 1811, p. 262. JAGNAUX, "Histoire de la Chimie," Vol. 1, Baudry et Cie, Paris, 1891, pp. 505-13. THOMSON, "History of Chemistry." Vol. 2, Colburu and Bentley, London, 1831, o. 268:. . 1. DAVY."The Collected Works of Sir Humohrv Vol. 1. . . Dam. Bart Smith, Elder and Co., London. 1839, p. 123. A. W. H., "Zur Eriunerunx an Friedrich W6hler." Ber., 15, 3127-290 (Part 2, 1882). OSWALD, "~'fivolutionde la Chimie au XIX' SiPcle;' Ref. (2), pp. 22-6. JAGNAUX, "Histoire de la Chimie," Ref. (S), Vol. 1, pp. 521-8. TORAUDB, "Bernard Conrtois et la DCcouverte de l'lode," Vigot Fdres, Paris, 1921,164 pp. HOEFER, "NouveUe Biographie G6nCrale." Didot FrCes, Paris, 1866. Article on "Ballard." S~DERBAUM, "Jac Berzelius Bref,'' Vd. 2, part 4, Almqvist and Wiksells. Upsala, 1912-1914, p. 67. BALARD. "Memoir on a Peculiar Substance Contained in Sea Water," Annals of Phil. [ I ] , 28, 381-7 (Nov., 1826); 411-24 (Dec., 1826). OSWALD, "L'fivolution de La Chimie au XIXDSiMe," Ref. ( Z ) , pp. 28-30. JAGNAUX, "Histoire de la Chimie." Ref. (8). Val. 1, pp. 52&49. MOISSAN, "Le Fluor et ses Compo&s," Ref. (I), pp. &9. KNOX,G. J., AND TAE RRV. TXOMAS KNOX,"On Fluorine," Phil. Mag. (31, 9, 107-9 (Aug., 1836): [3], 12, 1 0 5 6 Uan., 1838); G. J. KNOX,"Researches on Fluorine." ibid. 131, 16, 1 9 2 4 (Mar., 1840). HARROW, "Eminent Chemists of Our Time," D. Van Nostrand Co.,New York City, 1920, p. 138. STOCK,"Henri Maksan," Bw., 40, 5099-130 (Band 4, 1907). MO~SSAN, "Le Fluor et ses Compos&," Ref. (I), pp. 1-36. HARROW, "Eminent Chemists of Our Time," Ref. (21), p. 148. Ibid., p. 153. ANGLADA, Letter to the editors, Ann. chim. pkys. [2], 33, 222-3 (1826). LIEBIG,"Sur le B r h e , " ibid. [2], 33, 3 3 0 4 (1826). BALARD, "MCmoire sur une Substance particuli&re contenue dans l'eau de la mer." ibid. [21, 32,337-81 (1826). ''Rapport sur le MCmaire de M. VAUQUELIN, THENARD.AND GAY-LUSSAC, Balard relatif i une nouveUe Substance." ibid. [2], 32, 3 8 2 4 (1826); Annnls o j Phil. [I], 28, 42&6 (Dec.. 1826). DAVY,H.. "An Aceount of Some New Experiments on the Fluoric Compounds: with Some Observations on Other objects of Chemical I n q ~ . "Phil.-~,ans.. 104, 62-73 (1814). DAVY,H., "Some Experiments and Observations on the Substances Produced in Different Chemical Processes on muor Spar." ibid.. 103,263-79 (1813). AMP~RE, "Suite d'une Classification naturelle pour les Carps simples," Ann. chim. phys. 121. 2, 19-25 (May, 1816). FREMY,"Recherches sur les flumes," Canpt. rend., 38,393-7 (Feb. 27,1854).

."

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FREMY,"D&ompasitian des fluarures au rnoyen de la pile," Cornpt. rend., 40, 966-8 (Apr. 23, 1855). GORE,"On Hydrofluoric Add," Chem. N m s , 19, 74-5 (Feb. 12, 1869): J . Chem. Sac., Trans., 22,368-406 (1869); Phil. Trans., 159, 173 (1868). S M ~E., F., "Bromine and Its Discoverers, 18261926." J. CHEM.EDUC.,3, 3 8 2 4 (Apr.. 1926). WEHRLE,"Geschichte der Salzsiure." Carl Gerold, Vienna, 1819, pp. 834. HENRY,"Account of a Series of Experiments, Undertaken with the View of Decomposing the Muriatic Acid," Phil. Trans., 90, 188-203 (1800). GAY-Luss~c."Untersuehuugen iiber das Jod," Ostwald's Klassiker No. 4. Wilhelm Eugebnann, Leipzig, 1889, 52 pp.; Ann. chi%. phys. [I], 91, 5-160 (1813). LOUYET,"Nouvelles recherches sur I'isolement du fluor, la composition des fluorures, et le poids atomique du fluor," Compt. rend., 23,960-8 (Nov. 23. 1846): A m . . 64,23940 (Heft 2. 1848); "De la vbritahle nature de l'acide fluorhydriquc anhydre," Compt. fend.. 24,434-6 (Mar. 15. 1847). BALDWIN, R. T.. "History of the Chlorine Industry." J. CHRM.EDUC.,4, 313-9 (Mar., 1027). M o r s s a ~ ."Action d'un courant Uectrique sur l'adde fluorhydriquc," Comet. rend., 102, 15434 (June 28, 1886); 103,202-5 (July 19, 1886); 2 5 6 4 (July 26, 1886); Ann. chim. phys. [6], 12, 472-537 (Dec., 1887); Chem. N e w , 54, 51 (July 30, 1886); 80 (Aug. 13, 1886). NICKLBS,"Recherche du fluor. Action des acides sur le verre," Canpt. rend., 44, 679-81 (Mar. 30, 1857). BALARD, "Recherches sur La Nature des Combinaisons d6colorantes du Chlore," Ann. chim. phys. (21, 57, 22&304 (1834). AND DESORMES, "Dbco~verted'une substance nouvelle dans le Vareck CL~MENT par M. B. Courtois," ibid. [I], 88, 304-10 (1813). "Lettre de M. Humphry Davy sur la nouvelle substance decouverte par M. Courtois dans le sel de Vareck," aid. [I], $8, 322-9 (1813). Obituary of Balard, J. Chem. Soc., Abstr., 31, 512-4 (1877). RAMSAY,"Moissan Memorial Lecture;' J . Chem. Soc., Trans., 101, 477-88 (Part 1, 1912); "Chemical Society Memorial Lectures, 1901-1913," Vol. 2, Gurney and Jackson, London, 1914, pp. 189-98. TISSANDER,"Le Fluor." La Nature, 18 [I], 177-9 (Feb. 22. 1890). i r Humphry Davy, Bart.." Vol. 1, Dnvv, DR. JoRN, "The Collected Works of S Smith, Elder and Co., London. 1839, p. 400. TORAUDE, "Bernard C m t o i s et la D h u v e r t e de I'Iode," Ref. (13).pp. 41-2. "Classics of Science: Moissan's Artificial Diamonds," Sci. News Letter. 14, 99-100 (Aug. 18, 1928). M o r s s a ~ ,"The Electric Furnace," English translation by Lenher, Chemical Publishing Co., Esston, Pa., 1904, 305 pp. T o u u o s , "Bernard Courtois," Ref. ( 1 3 , p. 59. I W . , pp. 6 P 5 . STIEGLITZ,"Chemistry in Medicine," The Chemical Foundation, Inc., New York City, 1928, pp. 272-96. Article by Marine on "Iodine in the Prevention and Treatment of Goiter." LANDOLT, ''Carl L6wig.l' Ber.. 23, 1013 (Part 1, 1890); 905-9 (Part 3, 1890). GUTBIER,"Zur Erinnerung an Henri Moissan," Kommissionsverlag von Max Mencke. Erlangcn. 1908, pp. 2-3. T ~ S S A N D I"1.e ~ R ,Fluor," La Nature, 14 121, 363-6 (Nov. 6, 1886).

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THE DISCOVERY OF THk; ISLEMENTS. XVII

1939

"LC Fluor." ibid., 14 [2], 3 8 3 4 (Nov. 20, 1886). (6'0) MEWNIER, "Henri Moissan," ibid., 35 [I], 2 2 2 4 (Mar. 2, 1907). (61) GAIJTIER, "Zur Erimerung an Henri Moissan," Ref. (58), pp. 25-34. (62) GUTBIER, (fi3) Editor's Outlook, J. CHEM.EDUC..6, 1609-10 (Oct., 1929). (64) "Stock to Be Non-Resident Lecturer at Cornell." Ind. Eng. Chen., News Ed., 10, 20 (Jan. 10, 1932); cj. J. CHEM.EDUC.,9, ,586 (Mar., 1932). (fi.5) "A Monument to Henri Moissan," J. CHEM. EDUC.,9, 3934 (Feh., 1932).

The discovery of the elements. XVII. The halogen family

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