On distillation with sulphuric acid, it is converted into mesitylene C 9 H 12 (symmetrical trimethyl benzene).
CH: CH 2; isopropylethylene, (CH 3) 2 CH CH: CH 2; symmetrical methyl-ethyl-ethylene, CH 3 CH: CH C 2 H 5; unsymmetrical methyl-ethyl-ethylene, (CH 3)(C 2 H 5)C:CH 2 i and trimethyl ethylene, (CH3)2C:CH(CH3).
Ladenburg (Ann., 1875, 179, p. 163) to be symmetrical trimethyl benzene; terephthalic acid, the remaining isomer, must therefore be the para-compound.
The identity of the four valencies of the carbon atom follows from the fact that the heats of combustion of methane, ethane, propane, trimethyl methane, and tetramethyl methane, have a constant difference in the order given, viz.
The tertiary arsines, such as As(CH3)3, trimethyl arsine, and the quaternary arsonium iodides and hydroxides, (CH3)4AsI and (CH3)4AsOH, tetramethyl arsonium iodide and hydroxide, have been obtained.