The invention relates to phosphinites I of formulae (1) or (2), in which
R1, R2, R5, R6, R7, R8, R9 independently represent hydrogen, an alkyl or
alkylene group having 1 to 8 carbon atoms or an alkoxy group having 1 to
8 carbon atoms; R3 is H or methyl; R4 is i-propyl or t-butyl; X is F, Cl
or CF.sub.3 and n is 1 or 2 ##STR00001##