Symmetric and aliphatic tetralkylammonium cations (QA) form room temperature molten salts (RTMS) with bis(trifluoromethylsulfonyl)imide (TFSI). Tetrapentylammonium (TPA) is the smallest cation to form RTMS with TFSI. The viscosity and the specific conductivity of TPA-TFSI at 25 degreesC are 430 mPa.s and 0.154 mS . cm(-1), respectively. This is the first report of the preparation of RTMS based on symmetric QA.