The present invention relates to oxonium salts having [(R
o
)
3
O]
+
cations and sulfonium salts having [(R
o
)
3
S]
+
cations, where R
o
denotes straight-chain or branched alkyl groups having 1-8 C atoms or phenyl which is unsubstituted or substituted by R
o
, OR
o
, N(R
o
)
2
, CN or halogen, and anions selected from the group of [PF
x
(C
y
F
2y+1−z
H
z
)
6−x
]
−
anions, where 2≦x≦5, 1≦y≦8 and 0≦z≦2y+1, or anions selected from the group of [BF
n
(CN)
4−n
]
−
anions, where n=0, 1 , 2 or 3, or anions selected from the group of [(R
f1
SO
2
)
2
N]
−
anions or anions selected from the group of [BF
w
R
f2
4−w
]
−
anions, to processes for the preparation thereof, and to the use thereof, in particular for the preparation of ionic liquids.