m i HA 



METALS. 



of sMsWttis extensively medal asoorce of sulphur 

 of Miphuhe Mid. BOOM varieties of it decompose 

 to air, being gradually converted into sulphate of iron. 



TU fJUpJUate / inn m 



/re. and akfaroM fora two compound. : 



I. rratoeUorUsoriroa 

 1. PtnalorUofin 





1. Pr**Horide of in* in the anhydrous state (Fed) is obtained on 

 lassllii. dry hydrochloric aeid gM over iron filings heated to redness, 

 hydrogsn is evolved, and the salt sublimes in white micaoeoui scales. 

 IB Uw> hydratod condition it may bo prepared by dissolving iron in 

 hydrochloric *cid, and evaporating in vacuo; green crystals are then 

 produced (Fed + 4 Aq.), which must be piesuved in an atmoaphere 

 of hydrogen or of oarbouic acid. 



Other snstsli may be coated with iron by boiling them in a solution 

 of protochlurkie of iron containing chloride of ammonium and pieces 

 : . . - 



2. PmUoritU of in* (Fe.Cl,) (tttjuuUoridt). Obtained in brown 



of chlorine over iron heated to redness. It 



at a red beat, is soluble in alcohol or ether, and is very 

 xat. The kydrated perdtloride is deposited in Urge red 

 crystal* on evaporating a solution of the hydrated peroxide in hydro- 

 chloric acid. They contain six equivalents of water of crystallisation. 

 Solution of perchloride of iron has a great tendency to dissolve per- 

 oxide, and on evaporation the solution yields a confusedly crystalline 

 of uncertain composition. The following is a convenient method 

 of | TI paring a definite solution of perchloride of iron. Five parts of 

 iron filings are dissolved in twenty parts of the common strong 

 hydrochloric acid, the liquid filtered through asbestos, three additional 

 parts of the acid then poured in, and the whole heated to ebullition; 

 nitric acid is now gradually added till no more red fumes ore evolved, 

 wl.-n the iron will all be in the state of perchloride. If necessary, 

 the solution may be evaporated to the crystallising point ; if carefully 

 prepared it will contain no free arid. 



Solution of perchloride of iron mixed with alcohol forms the tincture 

 of tevjtucklartJt of iron used in medicine. 



Iron and iodine, 



Jron and bromine, and 



Iron nadjluorine form combinations corresponding to tho two chlo- 

 rides. The only one of importance is the 



../ inn (Kelt. This salt is used in medicine, and is 

 prepared by boiling iodine with excess of iron filings, or small nails, in 

 water. On evaporation, the solution yields green crystals, containing 

 I Aq. These crystals fuse on the application of a moderate heat, 

 give off their water of crystallisation, and on cooling solidify into a 

 steel-grey crystalline mass. In manipulating with iodide of iron, con- 

 tact of air should be avoided as much as possible, as an oxyiodidc is 

 very apt to form; the operations should also be conducted in iron 

 Yeanls, and when in solution a piece of iron wire should be immersed 

 in the liquid. 



Protoearbonatt of iron (FeO, CO J occurs native. It is from this ore 

 that most of the Knglish iron is obtained. [IRON, in NA i 

 It also exists, dissolved by the aid of carbonic acid, in certain natural 

 waters or chalybeate springs. It may be formed artificially by precipi- 

 tatiaga orotosah of iron with an alkaline carbonate: at fiwt it is white, 

 bot rapidly loses carbonic acid, absorbs oxygen from the air, becomes 

 grsen, black, and finally red (peroxide of iron). This change may be 

 considerably retarded by mixing it while moist with powdered "hit.- 

 sugar, and rapidly drying over a water-bath ; it then constitutes the 

 esrtomtir / iron m'(A ivjar of the London Pharmacopoeia. 



Pkutfkftm of iron are numerous, but ill defined. The principal are 

 these: 



1 . Phosphate of protoxide of iron. 



2. Phosphate of peroxide of iron. 



3. Pyrophosphate of peroxide of Iron. 



1. PktqAaU of mtoxidt of iron, or protmhotphate of iron (2FeO, 

 H, I This is obtained as a white precipitate on 



adding ordinary tnbasie phosphate of soda to protosulphate of iron. It 

 is insoluble in water, but soluble in solution of phosphoric acid, and 

 the Utter liquid, when mixed with sugar, constitutes the tyrnj, 

 fkati (or uprrpnoijAali) of iron used in medicine. 



Ao*** : ,/ yxruKfc of iron, or ptrpko^kale of iron (Fe.0., 

 P0 f + 4Aq.), falls as a white precipitate on mixing solutions of a pcrsaft 



-. and ordinary tribaaic phosphate of soda. Unlike th. 

 phosphate, H doss not absorb oxygen from the air, and, being of 

 constant composition, is frequently used in quantitative analysis as a 

 mesas of sMiawtinf phosphoric acid. It is insoluble in acetic acid, but 

 solabis in solution ofpsnostste of iron. 



S. PrnyAuqJ.au of ptraxid* of iron (m/nplwipnatt nf iron), (2Fe,0 :1 , 



powder produced by double decompout 

 p^^wiUidiba^ph^pl^^pyropbosphrtejof^da. It 



various names, the citro-amwtoniaeal-pyroplioiphate of iron and toda 

 being one of them. 

 XutjJuiia of iron are two : 



1. Protosulphato of iron. 



2. Persulphate of iron. 



1. ProlotulfJiatt of iron. Ortm rilriol. Goppena. (FeO, SO, -> 

 This salt is largely produced in the manufacture of .'. U also 



formed in the process for precipitating copper from the sohit 

 sulphate of copper obtained in certain metallurgical oprraiim 

 that metal. Old scrap iron is used for this purpose, and, i< 

 copper in solution, is obtained as stilpliatu of iron on evaporatn 

 liquor. Sulphate of iron may be formed on the small scale by dissolving 

 iron in dilute sulphuric acid. The following decomposition takes 

 placj : 



Fe + HO.SOj = FcO.SO, + II 



Iron. Sulphuric acid. 



11} ir^j n. 



On evaporating the solution the salt crystallises out in beautiful 

 bluish-green rhomboidal crystals. These, however, like all th. 

 salts of iron, must be exposed as little as possible to the air, for they 

 quickly absorb oxygen, and a separation into basic and neutral peraalta 

 results, thus : 



<FeO; 80, + O, = Fe.O,, SO, + Fe.O,, r 



'-.;.- ,,. 



Persulphate 

 of iron. 



Subaulphates of other composition ore also frequently produced. 



Protosulphate of iron is insoluble in alcohol, HoliiMr in twice its 

 weight of cold water, but much more so in hot water. When ! 

 it loses six equivalents of its water of crystallisation, at a red h. 

 decomposed into sulphurous and sulphuric acids, which escape, while 

 peroxide of iron (colcothar) remains. It is largely used in block 1 > 

 and in the manufacture of writing INK. 



J. /'. i->,il,,hntc n) iron ( Fe..(>,, 3SOJ. Five parts of crystals of proto- 

 Bulphate are di.-solved in wmter, one part >i Milphurir "n-iil add. 

 nitric acid poured into the hot solution till no more black co].. in 

 du. <<!. Alnni.linoe of nitrous vapours i ,.-l)ow 



solution, on evaporation to dryness, yields a buff-coloured mass of 



of iron, having the above composition. 



This salt occurs native. [IRON, Coquim'iii, in XAT. HIST. Div.] 

 Potattio-gu/phate of iron (Fe^O,, 3SO, + KO, SO, + MAq.) is a double 

 salt containing persulphate of iron and sulphate of potash. Corn - 

 ing salts with the other alkaline sulphates may also be formed. '1 . 

 crystallise, and, being isomorphous with common alum, are frequ 

 though erroneously, called i'rn alume. They are formed by the spon- 

 taneous evaporation of mixed solutions of the salts, are to some extent 

 used in medicine, but are liable to decompose. 



The iodate, bromojt, and jierr/ihrate of iron are indefinite, unim- 

 portant salts. 



v of iron. The protonitralc (FeO, NO.) is formed when . -old 

 nitric acid is saturated with protosulphide of iron lating 



the solution in vacuo, the salt crystallises out in pale green crystals 

 containing seven atoms of water. The crystals ar, Descent, and 



unstable. Tho pernitrate is produced when metallic iron in dissolved 

 in strong nitric acid. It is very difficult to crystallise, the solution on 

 evaporation depositing a basic salt. Solution of pernitrate of iron is 

 used in dyeing. 



a of iron. Many of these occur native. [Iiio.v, in 

 HIST. Drv,] 



Anenila and anenatn of iron. In cases of poisoning by arsenic, the 



best antidote to administer is freshly precipitated t j ron 



mixed with a little hydrate of magnesia. The efficiency of thi - 



dots dtp i the formation of pcrarsenite of iron, which is an 



bsolnble compound: that is, insoluble in water, but not altogether 



in tlir lii]uiiln of the stomach, which usually contain traces of 



.0 acids : the solution may, however be 



ted by mixing the oxide with magnesia, whirli m'utralises those 

 acids in a to more effectual manner than excess of peroxide of iron 

 would di i. 



/ trow, [ACETATE.] 



' and tannala of trim. [I.VK : TTritlny Inl.] 



Citrata of iron. A double citrate of iron and ammonia is obtained 

 li.. n freshly precipitated protoxide of iron is digs..] i acid 



and excess of ammonia added. The compound does not crystallise 

 but when the solution is evaporated to tho consistence of syrup and 

 spread over glass plates it dries up and forms brilliant transit 

 scales of garnet-red colour. 



of iron ami V ,-,,W i a nu-di, in.il agent of some repute. It 



, dissolving together three parts of citrate of i, 

 of titrate of ,,111111110, and scaling as just described. Tin- < -in 4 te a 

 '" """' >tu moist peroxide of 



rating and scaling ; ,-,nd i f double dcr 



ot sulphate of quint -te of soda. 



und of tartrate of iron and iiotash 

 of somewhat similar physical properties to the lost preparations, but 



