640 ANTIMONY. 







without crystallizing, when oxide of antimony has been dissolv- 

 ed in excess by the acid tartrate, in preparing the salt. Oxide 

 of antimony is precipitated by potash or ammonia from a 

 solution of this salt, when concentrated, but not when 

 diluted, owing to the solubility of oxide of antimony in 

 alkalies. Salts of the earths and basic metallic oxides, such as 

 barytes and oxide of silver, throw down from its solution s 

 compound of the tartrate of antimony, with tartrate of 

 barytes, tartrate of silver, &c (Wallquist.) Strong acids 

 decompose the salt, and produce a precipitate which is a mix- 

 ture of bitartrate of potash with oxide of antimony, or with a 

 subsalt of that oxide. Sulphuretted hydrogen gas throws down 

 the orange red sulphuret of antimony from a solution of the 

 tartrate, and this precipitate affords the most conclusive indica- 

 tion of the presence of antimony. The orange precipitate 

 should be collected, dried, and dissolved by heat in a few drops 

 of concentrated hydrochloric acid. When the acid solution is 

 dropped into a glass of water, the white and bulky hydrated 

 oxichloride of antimony precipitates. 



This salt was formerly described as a double tartrate of potash 

 and antimony, or, abstracting its water of crystallization, which 

 is differently stated at 2 and 3 equivalents, as KO, (C 4 H 2 O 5 ) 

 -fSbO 3 , (C 4 H 2 O 5 ). When the atomic weight of tartaric 

 acid is doubled, and it is represented as a bibasic acid, the for- 

 mula for dry tartar emetic becomes KO. SbO 3 , (C 8 H 4 O 10 ). 

 In comparing the last formula with that of bitartrate of potash, 

 represented also as a bibasic salt, KO. HO, (C 8 H 4 O 10 ), it is 

 observed that 1 eq. of oxide of antimony takes the place of 1 

 eq. of water, as base, although the former contains three eq. of 

 oxygen and the latter only one. Tartrate of potash and anti- 

 mony is, in this respect, an anomalous salt. Another equally re- 

 markable fact respecting this salt has been observed by M.Dumas, 

 namely, that 2 eq. of water are separated from the anhydrous 

 salt at 428, leaving a substance of which the elements are, 

 C 8 H 2 O 12 Sb K. The first part of this formula C 8 H 2 O 12 , 

 M. Dumas looks upon as a quadribasic salt-radical existing in 

 the tartrates, which in hydrated tartaric acid is united with 4H, 

 in bitartrate of potash with 3H + K, and in tartrate of antimony 

 and potash with Sb -f K. Here Sb is found equivalent to, and 

 capable of replacing 3 H, (note p. 542). Tartrate of antimony 

 and potash would, therefore, fall to be represented by K Sb, 

 (C 8 H 2 O 12 ) + 2HO + water of crystallization. 



