Bismuth arsenates Basic

Bismuth phosphates and various other bismuth salts (e.g. arsenate, basic sulfate, and titanate) are capable of producing benzene, as reported by Seiyama et al. [283]. A selectivity of 49% is reached with a combination 2Bi203 P205 at 500°C. Sakamoto etal. [271] varied the Bi/P ratio and stated that a 2/1 ratio gives the maximum selectivity. 

Nitrogen is unusual in forming so many oxides. The acidity of the Group V oxides falls from phosphorus, whose oxides are acidic, through arsenic and antimony whose oxides are amphoteric, to the basic oxide ofbismuth. This change is in accordance with the change from the non-metallic element, phosphorus, to the essentially metallic element, bismuth. The +5 oxides are found, in each case, to be more acidic than the corresponding + 3 oxides. 

Compare the acid-basic, reducing, and oxidizing properties of arsenic, antimony, and bismuth hydroxides. 

A basic arsenate, 2BiAs04.3Bi 203, has been prepared by the action of sodium arsenate upon an ammoniacal solution of bismuth citrate.3 It forms a gelatinous precipitate which resembles the corresponding phosphate in its chemical properties. 

Bismuth(III) oxide, Bi O is the compound produced by heating the metal, or its carbonate, in air. It is definitely a basic oxide, dissolving readily 111 acid solutions, and unlike the arsenic or antimony compounds, not amphiprotic in solution, although it forms stoichiometric addition compounds on heating with oxides of a number of other metals. It exists in three modifications, white rhombohedral, yellow rhombohedral, and gray-black cubical, Bismuth(II) oxide. BiO, has been produced by heating die basic oxalate. 

Note that tripositive nitrogen, phosphorus, and arsenic exist as oxy-acids or their derivatives, whereas the more basic tripositive antimony and bismuth exist as positive ions the latter two might be written as more fully hydrated forms, for example, (H20)2Bi(0H)J, but are more often represented as the simpler mono-oxygenated forms, consistent with known salts of the type (SbO)jSOi and BiOCl. Some (but not all) of such salts contain discrete MO+ ions. 

Lewis acidity, basicity, H-bonding and compiexing of organic arsenic, antimony and bismuth compounds ... 

In aqueous solution and in the absence of coordinating ligands, arsenic and antimony are present either as oxides, oxoanions, or their protonated forms such as As(OH)3. However, for bismuth a wide range of basic salts are known and various polynuclear cations have been proposed or... 

Lange, K. C. H. Klapoetke, T. M. Lewis acidity, basicity, H-bonding and complexing of organic arsenic antimony and bismuth compounds. Chem. Org. Arsenic, Antimony Bismuth Compd. Patai, S., Ed., Wiley New York, 1994, 66-315. 

The foundations of the modem science and the systematic investigation of the elements began in the Arabic world where experiments with scientific questions were well underway in the ninth-century ad. Jabir ibn Hayyan, one of the founding fathers of chemistry, was bom in Persia and a prolific scholar. He emphasized experimentation and invented a wide variety of laboratory equipment, as weU as a number of fundamental processes such as distillation and crystallization. He discovered and described many basic chemical substances - including hydrochloric and nitric acid, and the elements arsenic, antimony and bismuth - that are the basis of chemistry today. He was the first to purify and isolate sulfur and mercury as pure elements. He began to systematically describe the basic elements and provided the framework for the periodic table by distinguishing metals and nomnetals in his classification. 

---