What are described are
flame retardant mixtures comprisinga) salt of a phosphinic acid of the formula (I) in which R1 and R2 are independently
alkyl, cycloalkyl,
aryl or aralkyl that are optionally substituted, M is an m-valent cation, and m is 1 to 4, b) salt of a phosphinic acid of the formula (II) that differs from component a) in which R3 is optionally substituted
alkyl, cycloalkyl, cycloalkylalkyl,
aryl or aralkyl, preferably with
alkyl radicals as substituents, R4 is alkyl with an even number of carbon atoms, with the proviso that, if R1 and / or R2 are alkyl, R4 has twice, three times or four times the number of carbon atoms of R1 or R2,  M is an n-valent cation, and n is 1 to 4, c) organylphosphonate,d) phosphite,e)
silicate, alumosilicate and / or
silicon dioxide which is
solid at 25° C.,f) a representative selected from the group of
triazine complex,
polyphosphate,
hypophosphite,
nitrogen-containing diphosphate,
organophosphate,
phosphazene and / or polyphosphonate,g) optionally a representative selected from the group of
metal hydroxide,
metal carbonate,
metal borate,
zinc stannate and / or
intumescent additive, andh) optionally
pigment.The mixtures can be used for production of
flame-retardant
polymer compositions comprising
thermoplastic and elastomeric polymers that are of excellent suitability for production of cable sheaths or cable insulations.