Certain of the more outstanding examples of organic derivatives of arsenic and antimony are described briefly in the articles on these metalloids and further information can be gained from the monographs mentioned below in the bibliography. Both trialkyl- and triaryl-bismuthines have long been known and were formerly prepared by the interaction of alkyl or aryl halides and sodium or potassium bismuthides.
The use of Grignard reagents has considerably enlarged the bismuth series of organic compounds. Diphenyl-a-naphthylbis muthine and tri- a-naphthylbismuthine (melting points 118-119° C and 235° C) have been prepared in this way (F. Challenger, 1914), and a cyclic bismuth compound, ethylcyclobismuthopen tane has been prepared by the successive action on bismuth tri bromide of magnesium ethyl bromide and the dimagnesium com pound of I :5–dibromopentane (G. Griittner and M. Wiernik, 1915) ; it is a yellow viscous oil boiling at 108-112° C/18-2o mm. with an unpleasant odour and oxidising rapidly in air.
Organic derivatives of selenium (q.v.) and tellurium (q.v.) are mentioned under these headings. A remark able series of organic chromium compounds has been described by F. Hein (1919-24), who by the action of magnesium phenyl bromide either on chromyl chloride or on anhydrous chromic chloride obtained chromium pentaphenyl bromide,
an orange-brown amorphous substance converted by alcoholic potash into chromium pentaphenyl hydroxide, crystallising in golden-yellow leaflets. This basic hydroxide on treatment with acids loses a phenyl group giving rise to salts of the general type [Cr(C6H5)4]X (where X is the acid radical). Moreover, the mother-liquors from chromium pentaphenyl hy droxide contain chromium triphenyl hydroxide, which gives the corresponding salts
These organic derivatives indicate that chromium has valencies of 6, 5 and 4.
Platinic chloride was mixed with dry ether and the syrupy mixture added slowly to magnesium methyl iodide in ether. After adding water and extracting with benzene, the concentrated extract yielded yellow crystals of trimethyl platinic iodide,
which is converted by moist silver oxide into trimethyl platinic hydroxide, (CH3)3Pt.OH, a colourless base in soluble in water but dissolving in nitric acid to form the readily soluble nitrate,
The corresponding chloride,
crystallises from chloroform in colourless rhombic dodecahedra (W. J. Pope and S. J. Peachy, 1909).
Courtot, Le Magnesium en Chimie organique, A. Blanchard, Paris, 1926 ; W. G. Christiansen, Organic Derivatives of Antimony, Chemical Catalog Co., New York, 1925 ; G. W. Raiziss and J. L. Gavron, Organic Arsenical Compounds, Chemical Catalog Co., 1923 ; F. C. Whitmore, Organic Compounds of Mercury, Chemical Catalog Co., 1921 ; J. Houben, Die Methoden der organischen Chemie, Vol. IV., "Organometallverbindungen," by W. Schlenk, 2nd edition, Leipzig, 1924 ; G. T. Morgan, Organic Compounds of Arsenic and Antimony, Longmans Green & Co., 1918 ; H. Wren, Organometallic Compounds of Zinc and Magnesium, Gurney & Jackson, 1913 ; A. Bertheim, Handbuch der Organischen Arsenverbindungen, F. Enke, 1913 ; H. Schmidt, Die aromatischen Arsenverbindungen, J. Spring, 1912 ; J. N. Friend, A Text Book of Inorganic Chemistry, Vol. XI., "Organometallic Compounds," by A. E. and D. Goddard, 1929.
(G. T. M.)