Butyl chloride ions, decomposition

The reaction of lithium phosphinidodiborane with butyl lithium and borane will give phosphin-ido triborane and phosphinido tetraborane ions (9.70) and (9.71). These compounds are colourless crystals which dissolve in water without decomposition, but are oxidised in air. Potassium phosphinidodiborane, on the other hand, decomposes violently in water to give phosphine and hydrogen. Dry hydrogen chloride reacts with the sodium salt in ether solution to give m-phosphinidiborane (9.72), which is stable only below -20°C. 

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