| prov:value
| - Alkali metal and alkaline earth metal hydroxides, carbonates, bicarbonates and phosphates, for example the hydroxides, carbonates, bicarbonates and phosphates of lithium, sodium and potassium; ammonia, primary, secondary and tertiary amines and nitrogen heterocycles, for example compounds of the formulae VI and VII, ##STR9## in which R4 and R5 have the meanings given above for the formula I and R6
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