ZINC. 



and an atom of ciilorine, and tiie atom of zinc to weigh as 

 above, its conllituents ftiould be 



Chlorine - - - loo 



Zinc .... gi.6 



Zinc readily combines with iodine by heat. The com- 

 pound, or iodide, is white. It is volatile, and cryftallizes in 

 fine quadrangular prifms. It deliquefces in the air, and is 

 very foluble in water. The folution is colourlefs, and does 

 not cryftallize. Gay Lufi'ac has (hewn, that this com- 

 pound confifts of one atom iodine, and one atom zinc, or by 

 weight of 



Iodine - - - loo 



Zinc ... - 26.52 



No compound of zinc with fluorine is at prefent 

 known. Zinc does not combn>e with azote nor hydrogen ; 

 nor are we acquainted with any compound of this metal 

 with boron and fihcon. 



Zinc may be combined with phofphorus by dropping 

 fraall bits of phofphorus into it while in a ftate of fufion. 

 Phofphuret of zinc is of a white colour, and poffefles a me- 

 tallic luftr;, which more refembles lead than zinc. It is 

 foraewhat malleable. It emits the odour of phofphorus 

 when filed or hammered, and if expofed to a ftrong heat it 

 burns like zinc. Phofphorus alfo appears to combine with 

 the oxyd of zinc, and to form a peculiar compound. 



Sulphur cannot be combined artificially with zinc ; but 

 if melted with the oxyd of zinc a peculiar compound is 

 formed. A fimilar compound is formed when fulphuretted 

 hydrogen in combination with an alkali is dropped into a 

 folution of zinc. It is at firft white, but becomes darker 

 on drying. Dr. Thomfon coiifiders this compound as a 

 fulphuret of zinc. Mr. E. Davy afcertained, that when 

 the vapour of fulphur is pafled over zinc in fufion a 

 yellovvilh compound is obtained, fimilar in appearance to 

 blende. 



One of the moil common ores of zinc is blende, defcribed 

 below, and which is a fulphuret of zinc, compofed, accord- 

 ing to Dr. Thomfon's experiments, of 



Zinc - - - 100 



Sulphur - - - 48.84 



Hence he confiders it as a compound of one atom zinc, 

 and one atom fulphur. 



The alloys of zinc and the metals of the fixed alkalies 

 are fpeedily decompofed by expofure to the air or immer- 

 fion in water. We are not acquainted with the alloys of 

 zinc and the metallic bafes of the alkaline earths. 



Zinc may be combined with arfenic by diftilling a mix- 

 ture of it and arfenious acid. With iron, zinc combines 

 with difficulty ; the alloy when formed, according to Lewis, 

 is hard, fomewhat malleable, and of a white colour, like 

 filver. Mulouin has fhewn, that zinc may be ufed inflead 

 of tin for covering iron plates; a circumftance which de- 

 monftrates an affinity between the two metals. 



Zinc does not appear capable of combining with nickel 

 or cobalt by fufion. The alloys of zinc with manganefe, 

 cerium, and uranium, are unknown. 



For the other alloys of zinc, fee the different metals ; 

 particularly for the moft important of them or brafs, fee 

 Brass and Copper. 



Salts of Zinc Almoil all the acids aft with energy on 



zinc, in confequence of its powerful affinity for oxygen. 

 The falts of zinc, therefore, are very eafily formed, and 

 on account of their being but one oxyd of zinc are not 

 much liable to variation. 



I 



Nitrati of Zinc— The nitric acid attacks zinc with fuch 

 energy, that it is commonly neceffary to moderate its aftiou 

 by diluting it with water. Even tlien much heat is 

 evolved, and a flrong effervefcence is produced by the 

 efcape of nitrous oxyd gas. The folution is tranfparent 

 and colourlefs, very cauftic, and yields by evaporation flat, 

 ftriatedjtetrahedral prifms, terminated by four-fided pyramids. 

 Thtfe cryftals attraft moifture on expofure to the air, and 

 are foluble in water and alcohol. When heated they melt, 

 and if thrown on burning coals, detonate with a red 

 flame. 



Carbonate of Zinc. — Calamine, one of the ores of zinc, is 

 a native carbonate of zinc, as defcribed below. This fait 

 ufually exifts in the form of a white powder, and may be 

 obtained by precipitating zinc from its folution in acids by 

 an alkaline carbonate. 



Phofphate of Zinc. — The phofphoric acid unites in two 

 proportions with the oxyd of zinc. The neutral phofphate 

 is a taftelefs white powder infoluble in water. The bi- 

 phofphate is foluble in water, if not expofed to too great 

 a heat. It does not cryftallize, and is ilrongly acid. 



Sulphate of Zinc — Concentrated fulphuric acid fcarcely 

 ads upon zinc without the affiftance of heat ; but when 

 diluted it ads upon the metal very ftrongly, and hydrogen 

 gas is given out in abundance. In this cafe, the water is 

 decompofed, its oxygen combines with the metal, while its 

 hydrogen efcapes. The folution, when concentrated, yields 

 cryftals in abundance. 



This fait, formerly known under the name of luhite 

 vitriol, was difcovered in Germany, about the middle of 

 the i6th century. When quite pure, it is perfeftly white. 

 The form of its cryftals is that or flat quadrangular pili'ms, 

 terminated by four-fided pyramids. At a temperature of 

 60°, it diffolves in about 1.4 times its weight of water. In 

 boiling water, it diffolves in any quantity whatever. Tlie 

 conftituents of this fait are, 



I Atom of fulphuric acid - 

 I Atom of zinc 

 5 Atoms of water 



When heated, the cryftals part with their water, and if 

 the heat be ftrong, the whole of the acid likjwife feparate?, 

 and leaves the oxyd of zinc in a ftate of purity. See 

 ViTKiOL, White. 



Muriate of Zinc. — See Chloride of Zinc, fupra. 



Sulphite of Zinc. — This fait exifts in the form of cryllalf, 

 foluble in water, but infoluble in alcohol. On expofure to 

 the air, they are foon converted into the fulphate of zinc. 

 Fourcrov and Vauquelin defcribe a hypofulphite of zinc, 

 which affumes the form of four-fided prifms, terminated 

 by four-fided pyramids. They are folublt in water and 

 alcohol. 



Borate of Zinc is a white infoluble powder. It may te 

 formed by pouring borate of foda into the nitrate cr muri- 

 ate of zinc. 



Arfeniate of Zinc is a white infoluble powder, and may be 

 formed by mixing folutions of the alkaline arfeniates with 

 the fulphate of zinc. 



Acetate of Zinc. — This fait exifts in the form of rhom- 

 b'jidal or hexagonal plates of a talky appearance, and is not 

 very foluble in water. Solutions of this fait form an excel- 

 lent external application to inflammations. 



Oxalate of Zinc This fait is a white powder, little foluble 



