The invention relates to triazolopyrimidines of the formula I in which the index n and the substituents R, R1, R2 and X are as defined below: X is nitro, a group —C(S)NR3R4, a group —C(═N—OR5)(NR6R7) or a group —C(═N—NR8R9)(NR10R11), R is halogen, cyano, hydroxyl, cyanato, alkyl, alkenyl, alkynyl, haloalkyl, haloalkenyl, alkoxy, alkenyloxy, alkynyloxy, haloalkoxy, cycloalkyl, cycloalkenyl, cycloalkoxy, alkoxycarbonyl, alkenyloxycarbonyl, alkynyloxycarbonyl, aminocarbonyl, alkylaminocarbonyl, dialkylaminocarbonyl, alkoximinoalkyl, alkenyloximinocarbonyl, alkynyloximinoalkyl, alkylcarbonyl, alkenylcarbonyl, alkynylcarbonyl, cycloalkylcarbonyl, or a five- to ten-membered saturated, partially unsaturated or aromatic heterocycle which contains one, two, three or four heteroatoms from the group consisting of O, N or S; R1 is alkyl in which one carbon atom may be replaced by a silicon atom, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, phenyl, naphthyl, or a five- to ten-membered saturated, partially unsaturated or aromatic heterocycle which is attached via a carbon atom and which contains one, two, three or four heteroatoms, independently of one another selected from the group consisting of O, N and S, as ring members; where R1 may be substituted as defined in the description; R2 is alkyl, alkenyl or alkynyl which may be substituted as defined in the description; R3, R4, R5, R6, R7, R8, R9, R10 and R11 are, independently of one another, selected from the group consisting of hydrogen, alkyl, cycloalkyl, alkenyl or alkynyl, where the 4 lastmentioned radicals may be substituted as defined in the description; or R3 and R4, R6 and R7, R8 and R9 and/or R10 and R11 together with the nitrogen atom to which they are attached form a four-, five- or six-membered saturated or partially unsaturated ring which may be substituted as defined in the description; and n is 0 or an integer 1, 2, 3 or 4; and the agriculturally acceptable salts thereof, to crop protection compositions comprising at least one compound of the formula I and/or an agriculturally acceptable salt thereof and at least one liquid or solid carrier and to a method for controlling phytopathogenic harmful fungi.