Excerpts from -- 


J. W. Mellor

Comprehensive Treatise on Inorganic & Theoretical Chemistry

( Vol. IX -  Arsenic )


T. Bergman in his De Arsenico (Upsala, 1777), said that it is probable that arsenic was first discovered by those who wrought in the roasting and fusing of ores, for it would betray itself by its white smoke, its garlic smell, and its pernicious effects in depraving metals, and destroying life. In the 4th century BC, arsenic sulphide was designated sandarach by Aristotle...  arhenicum by Theophratos... and in the 1st century of our era, Dioscorides called the mineral sulphide arsenico... The sandarach of these early writers was probably the mineral now known as realgar, AsS; and arsenicum and auripigmentum, the mineral orpiment, As2S3... Pliny, in his Historia Naturalis... said:

"Sandarach is found in gold and silver mines. The redder it is, the more powerful its odour, the better its quality... Arsenicum is composed of the same matter as sandarach; the best in quality has the same color as that of the best gold, and that which is pale in color resembling sandarach is of inferior quality."

Pliny also confused white arsenic with ceruse; and the context of the Olympiodorus references to the preparation of alum shows that white arsenic was meant. Pliny also seems to have confused red lead with realgar... The term arsenic is derived from from the Greek arsenickos = arrevikos, meaning valiant or bold, in allusion, said R.J. Hauy, to the great energy with which it acts on other metals. F. von Kobell said the Greek term was derived from the Arabian word arsa naki ; S. Frankel, however, said that this term does not occur in the Arabian language; rather was the Greek term derived from the Persian word for arsenic, zarnach, zirnuk, or  zirne.

It is rather surprising that these early writers -- Diocorides, Pliny, Celus and Galen -- should mention several medicinal qualities of arsenical preparations, but did not mention the toxic properties of white arsenic --- i.e., arsenic trioxide. They must have had an impure form of this oxide since Pliny said that in order to increase the energy of arsenicum, it was heated in a new earthen vessel until it changed its color; and Dioscorides said that sandarach was mixed with carbon and calcined until it changed its color.

The 13th century Latin translation of Geber's Summa Perfectionis Magisterii shows that arsenicum album or white arsenic was obtained as a sublimate from arsenicum. He said that the product which has been sublimed cannot be inflamed like the impure raw arsenicum, because, when heated, it merely sublimes without inflammation. According to T. Bergman's De Arsenico (Upsala, 1777), the 11th century Arabian writer Avicenna said that there are three forms of arsenicum  --- white, yellow, and red --- and that the white is obtained from the other by sublimation... In the Breve breviorum de dono Dei, attributed to Roger Bacon, of the 13th century, it is stated that white arsenic is prepared by calcining orpiment with iron scales. The iron would have taken the sulphur, and the arsenic vapor set free would be oxidized to white arsenic. Both Geber, and Avicenna, recognized that arsenicum has many of the properties of sulphur; and A. Libavius, in his Commentationum Metallicarum (Francofurti, 1597), said:

"Arsenicum is a rich, inflammable mineral which is akin to sulphur, yet more virulent because of the salt combined with it; it is composed of a sulphurous richness with a little mercury and spirit of salt" ... According to Berthelot, metallic arsenic is first mentioned in a fragmental writing attributed to Zosimos of the 3rd or 4th century; and the preparation of white arsenic is described by Olympiodorus, a writer of the 5th century ... Albertus Magnus, in his 13th century work De Alchymia, said that arsenicum becomes metallic when heated with twice its weight of soap. Basil Valentine called arsenicum metallicum a bastard metal; and in the 17th century, N. Lemery obtained reguline arsenic --- metallic arsenic --- by heating white arsenic with potash and soap ... In the Middle Ages, arsenic received various names: Scherbenkobold, Napchenkobold, Goblet-fiend, Bowl-sprite, Cobaltu, etc...

F.B. Fittica stated that arsenic is not an element, but rather a compound of phosphorus, nitrogen and oxygen, PN2O; but C. Winkler, et al., showed that F.B. Fittica erred grievously in his speculation...

Arsenical Minerals :

Arsenides --- Algodonite, Cu6As --- arsenrgentite (huntilite), Ag3As --- arsenical copper (domeykite), Cu3As --- chloanthite, (white nickel ore), NiAs2, or, (Ni,Co,Fe)As2 --- leucopyrite, Fe3As4 --- lollingite, FeAs2 --- niccolite (nickeline, red nickel ore), NiAs --- rammelsbergite, (Ni,Co,Fe)As2 --- safflorite, (Co,Fe,Ni)As2 --- skutterudite, CoAs3 --- smaltite, CoAs2 --- speiss cobalt, (Co,Fe,Ni)As2 --- sperrylite, (Pt,Rh)(As,Sb)2.

Sulphides --- Orpiment, As2S3 --- realgar, AsS

Mixed Arsenides and Sulphides --- Alloclasite (Co,Fe)S(As,Bi) --- arsenical nickel, (Ni,Fe)AsS --- arsenopyrites (mispickel) --- baumhaurite, Pb4As6S13 --- binnite, Cu6As4S9 --- cobalt glance, (Co,Fe)(AsS) --- cobaltite, CoSAs --- corynite, (Ni,Fe)(As,Sb)S --- danaite  (glaucodote), (Fe,Co)(AsS) --- dufrenoysite, Pb2As2S5 --- enargite (clarite, luzonite), Cu3AsS4 --- epigenite (regnolite), Cu2Fe3As2S12 --- fahlerz ( tetrahedrite, annivite, sandbergerite,  julianite), (As,Sb)2S7(Cu2,Ag2,Fe,Zn)4 --- lengenbachite, Pb6(Ag,Cu)2As4S13 --- liveingite, Pb5As8S17 --- lorandite, TlAsS2 --- mercury fahlerz, schwatzite (hermesite), (Sb,As)2S7 --- mispickel (arsenopyrites) FeAsS --- pearceite, (Ag,Cu)16(Sb,As)2S11 --- polybasite, (Sb,As2S13)(Ag,Cu)18 --- proustite (light red silver) ore, Ag3AsS3 --- rathite, Pb3As4S9 --- sartorite, Pb(AsS2)3 --- sclerosase, PbAs2S7 ---  wolfachite, (Ni,Fe)(As,S,Sb)2 --- xanthoconite, Ag3AsS4.

Arsenites and Arsenates --- Adamite, Zn(ZnOH)AsO4 --- allactite, Mn3,Mn(OH)2(AsO4)2 --- ardennite, 10SiO2(As,V,P)2O3.10(Mn,Mg,Ca,Cu)O.6H2O --- armangite, Mn(AsO3)2 --- atelestite, (BiO)2.Bi(OH)2.AsO4 --- bayldonite, (Pb,Cu)2(OH)As)4.1/2H2O --- berzeliite, Mn,Ca2(AsO4)2.2H2O --- beudantite, (Cu,Pb)2Fe2O5(SO3)(P,As)2O5.H2O --- brandtite, Mn,Ca2(AsO4)2.2H2O --- cabrerite, (Ni,Mg,Co)2(AsO4)2.8H2O --- campylite, Pb5Cl(As,P)O4 --- carminite (carmine spar), Fe10Pb3(AsO4)2 --- caryinite, (Mn,Ca,Pb,Mg)3(AsO4)2 --- chlorotile, (CuOH)3Cu(OH)2AsO4 --- chondrarsenite, (Mn,Ca,Mg)8H2O --- concichalcite, (Cu,Ca)(CuOH)(As,P,V)O4.1/2H2O --- copper mica (chalcophyllite), (CuOH)5AsO4.3-1/2H2O --- cube ore (pharmacosiderite), Fe(FeOH)3(AsO4)3.6H2O --- discenite, (HOMn)2Mn3SiO3(AsO3)2 --- dixenite, Mn3(AsO3)2.MnSiO3.Mn(OH)2 --- duftile, Pb5(PbOH)(CuOH)7(AsO4)6 --- durangite, Na(Al,F)AsO4 --- ecdemite, Pb3As4O15C18 --- endlichite, Pb5Cl{(As,V)O4}3 --- erinite, Cu(CuOH)4(AsO4)3 --- euchroite, Cu(CuOH)AsO4.3H2O --- fermorite, (Cu,Sr)5(F,OH){(P,As)O4}3 --- finnemanite, Pb3(AsO3)2.PbCl --- flinkite, Mn{Mn(OH)2}2AsO4 --- fornesite, (Ni,Co)H.AsO4.3-1/2H2O --- georgiadesite, Pb5Cl4(AsO4)2 --- haemafibrite, (MnOH)3AsO4.H2O --- haematolite (diadelphite), (Mn,Al){Mn(OH)2}4AsO4--- haidingerite, CaHAsO4.H2O --- hedyphane, (Pb,Ca,Ba)5Cl(AsO4)3 --- henwoodite (chenevixite), (FeO)2Cu3(AsO4)2.H2O --- higginsite, Ca(CuOH)AsO4 --- haernesite, Mg3(AsO4)2.8H2O --- keottigite, (Zn,Co,Ni)3(AsO4)2.8H2O --- lavendulite, Cu3(AsO4)2.2H2O --- leuvochalcite, Cu2(OH)AsO4.H2O --- lindackerite, Ni3Cu6(OH)4(AsO4)4(SO4).5H2O --- liroconite, Al4Cu9(OH)15(AsO4)5.20H2O --- liskeardite, (Al,Fe)3(OH)6AsO4(SO4).5H2O --- manganostilbiite, Mn2(Mn3O7)(Sb,As)O4 --- mazapilite, Fe4(OH)6Ca3(AsO4)4.3H2O --- mimetestite, Pb4Cl(AsO4)3 --- mixite, BiCu10(OH)3(AsO4)5.7H2O --- nickel bloom (annabergite), Ni3(AsO4)2.8H2O --- olivenite, Cu(CuOH)AsO4 --- pharmacolite, CaHAsO4.2H2O --- picropharmacolite, (Ca,Mg)3(AsO4)2.8H2O --- pitticite, Fe2(OH)24{(As,P)O4}10(SO4)3.9H2O --- polyarsenite (see sarkinite) --- rhagite, Bi(BiO)9(AsO4)4.8H2O --- roesslerite, MgH AsO4.1/2H2O - roselite, (Ca,Co,Mg)3(AsO4)2.2H2O --- sarkinite, or polyarsenite, Mn(MnOH)AsO4 --- scorodite, FeAsO4.2H2O --- svavite, Cu5(F,OH,Cl)(AsO4)3 --- symplesite, Fe3(AsO4)2.8H2O --- synadelphite, (Mn,Al){Mn(OH)2}5(AsO4)2 --- tilasite, Ca(MgF)AsO4 --- trichalcite, Cu3(AsO4)2.5H2O --- trigonite, MnHAsO3.Pb3(AsO3)2 --- trippkeite, CuO.As2O3 --- traegerite, (UO2)3(AsO4)2.12H2O --- tyrolite, Cu(CuOH)4(AsO4)2.3-1/2H2O --- uranospinite, Ca(UO2)2(AsO4)2.8H2O --- veszelyite, {(Cu,Zn)OH}3{Cu(OH)2}(As,P)O42.6H2O --- walpurgite, Bi10(UO2)3(AsO4)7.10H2O --- wapplerite, (Ca,Mg)HAsO4.3-1/2H2O

The Extraction of Arsenic ~ Formerly, elemental arsenic was made by reducing arsenic trioxide by charcoal in clay crucibles covered by another crucible or a conical iron cap. The method was economical, but the product was grey and pulvurent, and contaminated with arsenic trioxide...

The main sources of arsenic are as a side-product in the treatment of ores from tin mines, tin-copper mines, and tin-copper-tungsten mines; the waste heaps of exhausted copper mines; the arsenical pyrites mined solely for arsenic. The common method of preparing arsenic is to heat mispickel, native arsenic, or leucopyrite in the absence of air when the arsenic sublimes. With mispickel: FeAsS = FeS + As, about half of the arsenic is recovered; and with leucopyrite: 4FeAs2 = Fe4As + 7S, the residue contains more arsenic than is represented by this equation. In both cases, therefore, the residues can be roasted in a reverberatory furnace so as to recover more of the arsenic in the form of arsenic trioxide. The distillation is performed in retorts consisting of fireclay tubes or pots, each fitted with a piece of sheet iron rolled so that one end fits the mouth of the retort, and the other end is luted to a fireclay receiver... With mispickel ores, arsenic sulfide collects in the receiver at the beginning of the operation. This can be prevented by mixing the ore with alkali or lime. In from 8-12 hours, the receivers are removed. Crystalline arsenic collects on the iron spiral in the mouth of the retort while the pulvurent arsenic collects in the cooler part of the receivers. The object is to collect as large a proportion of the crystalline form as possible...

M.G. Bachimont suggested heating the arsenical ore with ferrous chloride in closed vessels whereby arsenic trichloride is volatilized and iron sulphide or oxide remains. The arsenic trichloride is received is received in a soln of ferric chloride and arsenic precipitated from the soln by metallic iron. J. Robinson proposed to extract the arsenic as sulphide from arsenical ores by means of a soln. of sodium polysulphide, and precipitating the arsenic from the liquor…

Arsenic can be purified by mixing it with charcoal powder and subliming; the arsenic sulfide is most volatile and comes off before the arsenic. Any undecomposed pyrites, or earthy matrix remains as a residue. The sublimation is conducted in two crucibles mouth-to-mouth, and luted with fireclay. The under crucible is fitted into a hole in an iron plate to keep as much heat as possible away from the upper crucible… Some arsenic trioxide is nearly always found associated with the sublimed arsenic…

The Allotropic Forms of Arsenic ~ J.J. Berzelius, in his memoir Om allotropi, showed that arsenic can exist in two allotropic states. One of these, metallic or crystalline arsenic, or alpha-arsenic, is produced when arsenic vapor mixed with another heated gas is deposited on a part of the vessel which is not strongly heated. It is a dark grey, crystalline mass which oxidizes in air, especially at 40o, forming what he called "black, pulvurent suboxide." The other modification, amorphous or vitreous arsenic, or beta-arsenic, is produced when arsenic is very strongly heated, or when the vapor is condensed on a part of the vessel which is near the temperature at which arsenic volatilizes, so that the element is deposited in an atmosphere of its own vapor. This modification of arsenic forms a light grey vitreous mass which, according to Berzelius, is denser than the alpha-form, and remains unaltered in air even when finely powdered, and heated to 70o or 80o...

The Chemical Properties of Arsenic ~ J.J. Berzelius and A. Gelis observed that arsenic unites directly with sulfur when a mixture of the two elements is heated… R.H. Adie found that boiling conc. sulfuric acid dissolved arsenic with the evolution of sulfur dioxide and the formation of arsenic trioxide. The reaction begins at about 110o , and no hydrogen sulfide or arsine is formed… Both nitric acid and aqua regia oxidize arsenic with great vigor, forming arsenic trioxide and arsenic acid; if the acid be dilute, added J. Persone, a part of the acid is reduced to ammonia… J.W. Slater found that a mixture of potassium nitrate and arsenic detonates vigorously when ignited…

As A. Deschamps showed, most of the metals unite with arsenic, forming alloys or definite arsenides... Sodium arsenide is one of the primary products of the action of sodium hydroxide on arsenic, and the hydrolysis of this may be the source of arsine [arsenic trihydride, AsH3]... H. Davy, [et al.] obtained arsine by the action of water or dilute acids on the alkali arsenides... Metal salts, like antimony trichloride... may stimulate the formation of arsine... G.S. Serullas used an alloy of arsenic, antimony, and potassium obtained by igniting a mixture of antimony sulphide, arsenic trioxide, and cream of tartar, and P. Lebeau [et al.] obtained arsine free from hydrogen by the action of water or dilute acids on calcium arsenide, Ca3As2.... C. Himmelmann [showed] that arsenical liquids also furnish arsine when heated with aq. ammonia or ammonium chloride and zinc or iron... C.W. Scheele said that zinc, tin, and iron dissolve in aq. arsenic acid liberating this gas particularly when the dissolution if the metal is assisted by the presence of hydrochloric or sulphuric acid...

Arsine has a repulsive nauseating odor. It is extremely poisonous, and when diluted with much air produces nausea, eructation, giddiness, and oppression. A.F. Gehlen was one of its first victims. According to L. Gmelin, in order to detect a leak in his apparatus he smelt strongly at the joints; he found the leak, but died in 8 to 9 days from the effects of the inhalation, in spite of all remedial measures…

H. Reckleben and co-workers found that concentrated aq ammonia decomposes arsine incompletely with the separation of arsenic... R. Meissner found that with arsine dry mercurous chloride or mercuric chloride forms hydrogen chloride and solid hydrogen arsenide; and H. Rose represented the reaction with a solution with a solution of mercuric chloride: 3HgCl2 + AsH3 = 3HCl + As(HgCl)3...

V. de Luynes observed that with ammonium chloride, much ammonia is evolved and some arsenic trichloride is formed...

Aq soln of the alkali hydroxides and aq. ammonia react with arsenic trioxide, forming arsenites. The arsenites give a white precipitate when treated with calcium hydroxide soln, or a soln of a calcium salt, forming the arsenite. W. Wollaston also found that when calcium oxide is heated with arsenic trioxide, calcium arsenite and arsenic are formed, and the proportion of arsenite is greater the lower the temperature.

A warm solution of the trioxide in soda-lye reduces silver oxide to silver mirror; this soln. deposits normal silver arsenite when treated with acid. When the solution of the trioxide in soda-lye acts on mercuric oxide, it becomes grey, and forms an arsenite and some arsenate...

According to C. Bloxam, if a soln of sodium carbonate be boiled with an excess of arsenic trioxide, and a clear soln evaporated to dryness, sodium meta-arsenite, NaAsO2 is formed; but if a mixture of dry sodium carbonate and arsenic trioxide be heated to redness, a mixture of arsenite and arsenate is formed.

According to C. Reichard, when sodium meta-arsenite is treated with silver nitrate, salts Ag6As4O9 are formed.

J. Berzelius reported the formation of antimony arsenate as a white precipitate on adding potassium metarsenate to a hydrochloric acid soln of antimony trichloride...

J. Berzelius observed that a mercurous arsenite is formed by digesting mercury with an aq soln of arsenic trioxide; and J. Simon obtained a white precipitate of mercury arsenite by treating mercurous nitrate with a soln of arsenic trioxide or potassium arsenite.

Arsenic Pentoxide ( Arsenic acid, As2O5 ) ~ P. Macquer found that the residue obtained after distilling nitric acid from a mixture of potassium nitrate and arsenic trioxide furnished a crystallizable salt which he called sel neutre arsenical. Paracelsus had previously applied the term arsenicum fixum to the product obtained by heating a mixture of arsenic trioxide and potassium nitrate; and Libavius called it butyrum arsenici -- butter of arsenic --- although this term was used for arsenic trichloride. These preparations were all impure alkali arsenates... C. Linville prepared the alkali arsenates by roasting spiess with sodium carbonate and extracting the soluble arsenate from the cold mass...

The finer the particles, the faster the reaction; the more vigorously the soln is agitated, the faster the oxidation; the more conc. the nitric acid the faster the oxidation...

All the water can be driven off at 180o; and the pentoxide is stable below 400o; hence, 180-200o is a convenient temperature for the dehydration of arsenic acid.

Water converts it to the hydrate or arsenic acid, H3AsO4. Kopp evaporated an aq soln between 140-180o, and obtained a hard mass with the composition of the dihydrate, As2O5.2H2O, or pyroarsenic acid, H4As2O7.

J. Berzelius reported mercurous metarsenate to be produced as a white non-crystalline mass when mercuric oxide is mixed with an aq soln of arsenic acid and boiled to dryness; the dry mass is triturated with cold water, washed, and dried on a water-bath...

Hydrated sodium hydroarsenate, Na2HAsO4, is produced when a soln of arsenic acid is mixed with a large excess of sodium carbonate and allowed to crystallize...

Aq soln of the alkali hydroxides and aq ammonia react with arsenic trioxide, forming arsenites...

E. Mitscherlich prepared anhydrous potassium orthoarsenate, K3AsO4, by heating a mixture of the hydroarsenate with potassium carbonate as in the case of the sodium salt. T. Graham also found that this salt crystallizes in deliquescent needles from a soln of arsenic acid in an excess of potash-lye... C. Scheele obtained potassium hydroarsenate, K2HAsO4.H2O by adding potassium carbonate to a soln of arsenic acid so long as effervescence continues; he obtained the solid by evaporating the solution to dryness, and fusing the product to form a white glass...

P. Macquer, et al., melted together equal parts of arsenic trioxide and potassium nitrate, and found that potassium dihydroarsenate, KH2AsO4, crystallized from the aq soln. E. Mitscherlich obtained it by crystallizing from a mixture of arsenic acid with an aq soln of potassium carbonate so long as the soln reddens litmus, and from a soln of potash-lye and arsenic acid, neutral to vegetable colors.

C. Scheele, et al., prepared ammonium hydroarsenate (NH4)2HAsO4, by adding ammonia to a conc aq soln of arsenic acid until a precipitate is formed, warming the liquid until the precipitate dissolves, and allowing the soln to crystallize...

When a soln of silver nitrate is treated with arsenates of ammonia, potassium or sodium, or with arsenic acid, brownish-red silver orthoarsenate, Ag3AsO4, is precipitated... The precipitate is dark purple if the soln of silver nitrate be boiling, and a concn of arsenic acid be the precipitant.

T. Thomson found sodium orthoarsenate gives a yellowish-white precipitate of gold arsenate when added to a warm soln of auric chloride...

Gold is precipitated when an aq soln of arsenic trioxide is added to a soln of auric chloride. A. Stavenhagen reported gold arsenite, AuAsO3.H2O to be formed when a soln of auric chloride in 50% alcohol is treated with normal potassium arsenite. The pale brown solid slowly decomposes at 20o, rapidly at a higher temp, forming gold arsenide and gold. The arsenite is freely soluble in water, in an excess of the precipitating agents, in aq ammonia, and in dil acids.

Arsenic Suboxide and Trioxide ~ J.J. Berzelius regarded the black film which forms on the surface of arsenic as arsenic suboxide, and P.A. von Bonsdorff represented it as arsenic hemioxide, As2O. J.J. Berzelius also said that the suboxide is produced as a dark brown sublimate which first appears during the preparation of arsenic; and J.W. Retgers observed the brown film as produced along with the arsenic mirror during the sublimation of arsenic. E. Mitchell believed that the suboxide is an intermediate product in the production of arsenic, and is the cause of the garlic odor. He also said that the suboxide is more volatile than arsenic trioxide. It is not unlikely that E. Mitchell mistook the amorphous arsenic for arsenic hemioxide. J.W. Retgers supposed that the alleged suboxide is truly a chemical individual, but A. Guether, and A. Suckow showed that the suboxide is probably a mixture of arsenic and arsenic trioxide.

As indicated in connection with the history of arsenic, the 12th century Arabian chemists alluded to white arsenic, and G. Brandt showed that arsenicum album is the oxide or calx of arsenic. In 1747, J.G. Wallerius spoke of arsenicum nativum, arsenicum faricaceum, or farina arsenicalis, and arsenicum cristallinum. The arsenic-meal, furnace fume, or white arsenic was the arsenicum calciforme of A. Cronstedt, and the arsenicum cubicum of C. Linnaeus. This oxide received various names during the Middle Ages --- white arsenic, arsenic, flowers of arsenic, rat-poison, poison meal, furnace fume, arsenious acid, etc. The modern designation is arsenic trioxide, As2O3, or As4O6. The formation of arsenic oxide during the oxidation of arsenic has already been discussed. It is also produced when arsenic, mispickel, or arsenical pyrites alone or mixed with other ores, is roasted in air. With lollingite, arsenic vapor is given off at a dull red-heat, and at a higher temperature, arsenic trioxide is produced; the iron is nearly all converted into ferric oxide, and but a small proportion of ferric arsenate is formed. When mispickel is heated in air, arsenic sulfide vapor is evolved below a red heat; but at a higher temperature, ferric oxide, sulfate, and arsenate are formed, while sulfur dioxide and arsenic trioxide are given off.

Arseniferous ores are a by-product from the tin mines of Cornwall, and their treatment is accordingly connected with the production of tin and tungsten… The oxidized sulfur and arsenic vapors pass zig-zag over a large condensing surface. The sulfur vapors escape, and dark grey, crude arsenic or arsenic soot is collected. It contains 4-10% of carbon and sulfur. The arsenic soot is refined by recalcination in a flat-bottomed reverbatory furnace using a smokeless fuel --- say a mixture of coke and anthracite --- and connected with a series of zig-zag condensing chambers. The charge is fed from the top, and paddled down the side-doors while being roasted. The first condensing chamber collects the slag arsenic, which is reground and calcined; in the other chambers, snow-white, crystalline arsenic trioxide collects on the walls, often in stalactitic forms… About 60% of arsenic is recovered from the ores, while 40% is lost in the slimes. The mispickel ores contain from 10 to 30% of arsenic…

According to H. Rose, the crystallization of arsenic trioxide from soln is attended by crystalloluminescence. He said:

“When from one to one and a half parts of transparent arsenic trioxide are dissolved by half an hour’s boiling, in a mixture of 6 parts fuming hydrochloric acid with two parts of water, and the soln left to cool as slowly as possible, the arsenic trioxide crystallizes in transparent octahedral and the formation of each crystal is accompanied by a flash of light; on agitation, many new crystals are formed, and a corresponding number of sparks is produced. If from 4 to 6 parts of arsenic-glass are dissolved in the acid, the light produced by the crystallization is sufficient to illuminate a dark room. As long as the deposition of crystals goes on, so long is light perceived on agitating the liquid; and this appearance may be visible on the second, and even, though very faintly, on the third evening. If the liquid be then boiled, so as to dissolve the remaining portion of the glassy oxide, crystallization again takes place, accompanied by the emission of light, though not so bright as before. If the liquid be rapidly cooled, the acid separates in the pulvurent state, and little or no light is emitted. A soln of arsenic trioxide in a hot mixture of hydrochloric with sufficient nitric acid to convert the whole of the arsenic trioxide into the pentoxide, likewise emits a strong light as the acid crystallizes. Boiling dilute sulfuric acid dissolves arsenic trioxide in smaller quantity, and exhibits only occasional luminosity. Nitric and acetic acids, which dissolve still less of the arsenic trioxide, exhibit no luminosity whatever. Arsenic trioxide which has acquired the porcelainic texture, and also arsenic-meal, likewise exhibits, when dissolved in hydrochloric acid, a very feeble luminosity on agitation.”

When an aq soln of arsenic trioxide is treated with an excess of sodium carbonate, it is readily oxidized by the oxygen of the air… Arsenic trioxide is oxidized to the pentoxide by nitric acid… with the conc acid, nitrogen oxides are formed. P. Askenasy and coworkers found that arsenic trioxide is oxidized to arsenic acid by nitric acid over 50% concentration…

Aq soln of the alkali hydroxides and aq ammonia react with arsenic trioxide, forming arsenites. The arsenites give a white precipitate when treated with calcium hydroxide soln, or a soln of a calcium salt, forming the arsenite. W. H. Wollaston also found that calcium oxide when heated with arsenic trioxide forms calcium arsenate and arsenic, and… some arsenite is produced --- the proportion of arsenite is greater the lower the temperature…

According to C. Bloxam, if a soln of sodium carbonate be boiled with an excess of arsenic trioxide, and the clear soln evaporated to dryness, sodium metarsenite, NaAsO2 is formed; but if a mixture of dry sodium carbonate and arsenic trioxide be heated to redness, a mixture of arsenite and arsenate is formed…

Arsenic Trichloride ~  In 1648, J. Glauber described the preparation of butyrum arsenici  (butter of arsenic) by heating in a retort a powdered mixture of one part of white arsenic, two parts of common salt, and four parts of vitriol calcined white. A thick oil was obtained in the receiver. N. Lemery obtained it by distilling a mixture of equal parts of white arsenic and corrosive sublimate; white arsenic does not give so good results as arsenic itself. J. Davies’ analysis showed that butter of arsenic is really arsenic trichloride, AsCl3

Arsenic trichloride, at ordinary temp., is a transparent, colorless, oily liquid, which fumes in air… b.p. 132o… It is doubtful if arsenic pentachloride, AsCl5, has ever been isolated, and a similar remark applies to arsenyl chloride, AsOCl…

Arsenic trichloride can be obtained by chlorinating arsenic, arsenic tri- or penta-oxide, or arsenic sulphide….

The trichloride is formed by the action of arsenic on numerous chlorides; thus… F. Semi [formed it by the action of] ammonium chloride… F. Selmi, H. Captaine, and H. Ludwig prepared the trichloride by heating arsenic with six times its weight of mercuric chloride… Other chlorinating agents can be used with arsenic trioxide; J.B.A. Dumas heated arsenic trioxide with sodium chloride and sulphuric acid, and F. Selmi substituted lead chloride for the sodium chloride. Other chlorinating agents can be used with arsenic trioxide. Thus, V.de Luynes [used] ammonium chloride… H. Rose, and J. von Liebig and F. Wohler obtained a similar result by treating arsenic acid or an alkali arsenate with sodium chloride and sulphuric acid. The reducing action of hydrochloric acid on arsenic acid has been studied by C.R. Fesenius and A. Souchay, K. Rohre, and J. Mayrhofer. E. Fischer showed that the reaction is greatly accelerated in the presence of ferrous chloride; A. Classen and R. Ludwig, in the presence of ferrous sulphate… L. Ramadier, methyl alcohol… H. Rose found that arsenic trichloride can be removed from alkali arsenates or arsenic acid by repeatedly heating them with ammonium chloride… J. Clark found that ferric chloride facilitates the chlorination of the sulphide by hydrochloric acid. C.R. Fresenius treated the sulphide with a mixture of ammonium chloride and nitrate… H. Ludwid, with mercuric chloride; and C. F. Rammelsberg, with cuprous chloride…

J. Davy made arsenic trichloride by heating a mixture of sulfuric acid and a sat. soln of arsenic trioxide in conc. hydrochloric acid... J. Dumas heated arsenic trioxide with sodium chloride and sulfuric acid...

J. Mayrhofer found that on distilling a mixture of arsenic acid (arsenic pentoxide) with fuming hydrochloric acid, much arsenic trichloride is formed... O. Hehner found that the presence of organic matter favors the reduction of the pentoxide and the formation of the volatile chloride... In the presence of cuprous chloride, ferrous sulfate, or ferrous chloride, arsenic acid is readily converted into the volatile chloride...

L. Lindet observed that in the presence of hydrochloric acid… gold chloride is dissolved without decomposition [in arsenic trichloride]…

S. Hilpert and F. Herrmann found that finely-divided, reduced silver and arsenic trichloride, when heated in a sealed tube, form silver arsenochloride, 7Ag.2AsCl3.

According to W. Wallace and F. Penny, and L. Hurtzig and A. Geuther, a mole of boiling arsenic trichloride dissolves a mole of arsenic oxide, forming arsenic oxychloride,or arsenyl monochloride, AsOCl. A similar soln was obtained by passing hydrogen chloride into water with arsenic trioxide in suspension until the solid has disappeared. If the soln be distilled until it begins to foam, the residue forms a soln of arsenic trioxide in arsenic trichloride, and beneath this is a brown, viscid mass of the oxychloride. If the temp of distillation be too high, the residue has the composition of AsOCl.As2O3. Again, if the arsenic chloride be mixed with sufficient water, and allowed to stand a few days, stellate masses of crystals of the monohydrate, AsOCl.H2O, are formed. If some ammonium chloride be placed in a solution of arsenic trichloride in water acidified with hydrochloric acid to prevent the separation of arsenic oxychloride, snow-white needles of ammonium oxyarsenotrichloride, 2NH4Cl.AsOCl, or (NH4)2AsOCl3, are formed…

Arsenic & Health ~ The white arsenic is regularly eaten by some of the peasants. The doses taken are at first small, and they are progressively increased so that the arsenic-eaters can swallow with impunity 4 or 5 grains of arsenious oxide at a time. It is said that the object of the arsenic-eater is to be able to endure greater fatigue in mountain climbing by increasing the respiratory power. This recalls the medicinal use of arsenic in cases of asthma and other chest diseases. It is also said that the arsenic-eater becomes plump and fat, and the skin greatly improved...

It is also said that in some parts of India, particularly in Punjab, arsenic-eating is practiced as an aphrodisiac. According to C. Heisch's report, since the practice of arsenic-eating has begun, it can only be left off very gradually diminishing the daily dose, as a sudden cessation causes sickness, burning pains in the stomach, and other symptoms of poisoning, very speedily followed by death. J.F.W. Johnston said that, as a rule, arsenic eaters are long-lived, and are peculiarly exempt from infectious diseases, fevers, etc, but unless they gradually give up the practice invariably die suddenly. It is further stated:

In this part of the world, when a graveyard is full, it is shut up for about 12 years, when all the graves which are not private property by purchase are dug up, the bones are collected in the charnel-house, the ground is plowed over, and burying begins again. On these occasions the bodies of arsenic-eaters are found almost unchanged, and recognizable by their friends. Many people suppose that the finding of their bodies is the origin of the story of the vampire...

In chronic poisoning with small doses, arsenic is not classed as a cumulative poison. There is a loss of appetite, nausea, perhaps vomiting, slight abdominal pain, and mild diarrhea. With the slow poisoning by repeated small doses, the illness may resemble in miniature that produced by large doses... There may be a slight yellowness or a brown pigmentation of the skin best marked about the neck. There is a general increase of the epiderm scales, called keratosis... The exanthema sometimes produced is called exzema arsenicale. The nervous system is nearly always disturbed... There may be fainting, and paralysis of the muscles of the limbs... ataxic gait, and severe darting pains in the limbs, and rapid muscular atrophy...

According to S. Delepine, the inhalation of air charged with fumes of arsenic trichloride or the direct application of undiluted arsenic trichloride to the skin rapidly causes death by acute arsenic poisoning. The application of the liquid to the skin results immediately in necrosis; this is considerably retarded by washing within one minute of the application, but washing after five minutes has no effect... The symptoms of poisoning by arsenic trichloride include laryngeal obstruction, dyspnoea, and convulsions.

Arsine has a repulsive nauseating odor. It is extremely poisonous, and when diluted with much air produces nausea, eructation, giddiness, and oppression…

Modern Arsenic Therapy

In 1996, Chinese physicians at Harbin and Shanghai announced their successful treatment of Acute Promyelocytic Leukemia (APL) with arsenic trioxide, which induced complete remission of the cancer. Test-tube studies have indicated that the therapy may be effective against other leukemias and some tumors including prostate and breast cancer. The results were replicated in 1998 by physicians at Memorial Sloan-kettering Cancer Center and Cornell University Medical College, and reported in The New England Journal of Medicine (5 November 1998):

"Treatment was supplied by an aqueous solution in 10-ml vials containing 1 mg of drug per milliliter. The drug was further diluted in 500 ml of 5% dextrose solution and infused intravenously over a period of 2 to 4 hours once per day. The initial cohort of patients received either 10 or 15 mg of arsenic trioxide per day as a fixed dose, but the referral of two children to the study prompted conversion to a weight-adjusted regimen (0.15 mg per kilogram of body weight per day). The drug was given daily until visible leukemia blasts and promyelocytes were eliminated from the bone marrow and the residual blast count was no more than 5% of marrow mononuclear cells. Patients who had complete remission were eligible for treatment with additional courses of therapy 3 to 6 weeks after the preceding course. Subsequent courses were generally given at a dose of 0.15 mg per kilogram per day for a cumulative total of 25 days; the drug was administered either daily or on a weekends-only schedule, for a maximum total of 6 courses over a period of approximately 10 months...

"Common adverse reactions included light-headedness during the infusion, fatigue, musculoskeletal pain, and mild hyperglycemia...

"In summary, arsenic trioxide can induce a complete remission in patients with APL who have relapsed after extensive prior therapy. This drug causes partial but incomplete cytodifferentiation of leukemic cells, followed by caspase activation and induction of apoptosis. The striking degree of activity in this disease, plus their lack of specificity of APL-specific proteins, suggests that they may warrant further study as therapy for other neoplastic diseases."

When it is prepared as a homeopathic remedy (Arsenicum Album), arsenic oxide also can act as a remedy for arsenic poisoning. According to research published by Prof. Khuda-Bukhsh, et al., in BMC Complementary and Alternative Medicine (October 2003), Arsenicum Album reduces liver damage caused by arsenic. Researchers at the University of Kalyani (West Bengal), searching for a way to deal with arsenic poisoning in drinking water, found positive results from Arsenicum Album in mice, and it is believed that the same treatment can be effective for humans also:

"The potentized homeopathic drug Arsenicum Album not only has the ability to help remove arsenic from the body, but these drugs in microdoses appear to have the ability to detoxify the ill-effects produced by arsenic in mice... An early human clinical trial may be worth pursuing to verify the efficacy of the homeopathic drug on human volunteers living in arsenic infested areas...

"It is quite amazing that such microdoses of a potentized homeopathic drug which is produced by the dilution and succession of the toxic substance itself were capable of bringing about such spectacular enzymatic alterations in mice treated with a toxic dose of arsenic oxide. This is more fascinating because the dilution at which the drug appeared to be effective was so high that the chances of even a single original molecule being in them was theoretically almost impossible...

"Any attempt to explain the mechanism of action of the homeopathic drug would be highly speculative at the present state of our knowledge, although it could play a role in regulating genes."