196 PROFESSOR LETTS AND N. COLLIE ON THE 
oil of vitriol is poured on to the chloride, an immediate effervescence occurs 
and clouds of hydrochloric acid are produced. Heated on the water bath, the 
mixture grows dark and eventually becomes completely liquid, provided that 
an excess of sulphuric acid has been taken. As soon as the whole of the 
hydrochloric acid has been driven off, the mixture is poured into a small 
quantity of cold water. A solid substance of a grey colour is precipitated, 
which by washing with a little cold water becomes free from sulphuric acid. 
It is then boiled with a tolerably large quantity of water, when it almost 
completely dissolves, leaving, however, a slight residue containing most of 
the black colouring matter. On cooling, almost colourless crystals are 
deposited, which are apparently rhombohedral plates united into spear-shaped 
forms. 
A single recrystallisation gives the new compound in a state of purity. 
Its analysis shows it to be the—- 
Acid Sulphate of Tetrabenzyl-Phosphonium.—The chloride has therefore 
been acted on by sulphuric acid in the same manner as common salt. Its 
analysis gave the following numbers :— 
‘397 erm. gave ‘9907 CO, = 68:1 per cent. carbon. 
"B07 ge Sh R216 BO k= Sed ayy ilindrocen: 
5252 =,,_~Ss,, . *2445 BaSO,= 16-0 » sulphuric anhydride. 
Obtained. Calculated for (C,;H,),PHSO,. 
Carbon, : é ' 681 68:3 
Hydrogen, . : 5 61 : 4 : 5°9 
Sulphuric anhydride, . 16:0 : : § 16:2 
Acid sulphate of tetrabenzyl-phosphonium is rather more soluble in water 
than the chloride, and very much less so than the normal sulphate ; it readily 
crystallises from hot water. The addition of hydrochloric acid to its solution 
causes the precipitation of the chloride. It has a sour taste, and its solution 
reddens litmus paper. 
It does not suffer any loss when heated to 100° C., and therefore contains 
no water of crystallisation. 
It fuses at 217° C., suddenly effervesces at higher temperatures, and suffers 
decomposition (see p. 214). 
Action of Hydrate of Barium on the Acid Sulphate—The action which 
occurs when solutions of these two bodies are mixed varies in a remarkable 
manner with the conditions of the experiment. 
