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.
The tetramethyl derivative, amalic acid, C$(CH3)4N407, has been prepared by oxidizing caffeine with chlorine water, and forms colourless crystals which are only slightly soluble in hot water.
Campholic acid, C 1 oH 18 0 2, is tetramethyl-126.96.36.199-cyclo-pentane acid-3.
Tetramethyl-diamido-benzophenone or Michler's ketone, CO[C6H4N (CH3)2]2, melting at 173°, is of technical importance, as by condensation with various substances it can be made to yield dye-stuffs.
By distilling an alloy of antimony and sodium with mythyl iodide, mixed with sand, trimethyl stibine, Sb(CH 3) 3 i is obtained; this combines with excess of methyl iodide to form tetramethyl stibonium iodide, Sb(CH 3) 4 1.