Crystal indifferent solvents

The reaction must be carried out in an indifferent solvent. Thi.s compound forms yellowish-white crystals, M.pt. 200° C., is readily soluble in carbon disulphide, chloroform, and absolute alcohol, sparingly soluble in petroleum ether or benzene and insoluble in ordinary ether. With water it yields triphenylarsine oxide, and with hydrogen sulphide or ammonium pentasulphide gives triphenylarsine sulphide. Studies of... 

The unsaturated character of these trialkyl esters was shown by the ease with which they were attacked by nitric acid, but still more clearly by the formation, with evolution of heat, of stable crystalline addition compounds when they were mixed with cuprous halides. Thus CuC1.P(OC2H5)3 was described as consisting of colourless crystals melting at 190° to 192° C. and soluble in organic solvents.4 This property they share with phosphine, alkylphosphines and phosphorus trihalides. The phosphoric esters were quite indifferent to cuprous halides. Nor were such addition compounds formed either by phosphorous acid itself or by the dialkyl esters, which may show that the latter compounds have the unsymmetrical formula. Phosphorous acid probably exists in both forms, but first as P(OH)3, i.e. when produced from PC13 and Ha0.5 This may be transformed into the unsym-metrieal form through an addition compound HC1.P(0H)3,4 and probably also exists in the form of complex molecules, such as... 

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