The structure of the title compound, [Li(BF₄)(CH₃CN)]_n, consists of a layered arrangement parallel to (100) in which the Li⁺ cations are coordinated by three F atoms from three tetra­fluoridoborate (BF₄⁻) anions and an N atom from an acetonitrile mol­ecule. The BF₄⁻ anion is coordinated to three different Li⁺ cations though three F atoms. The structure can be described as being built from vertex-shared BF₄ and LiF₃(NCCH₃) tetra­hedra. These tetra­hedra reside around a crystallographic inversion center and form 8-membered rings.

In the title compound, [Li(CH₃CN)₄]PF₆·CH₃CN, the asymmetric unit consists of three independent tetra­hedral [Li(CH₃CN)₄]⁺ cations, three uncoordinated PF₆⁻ anions and three uncoordinated CH₃CN solvent mol­ecules. The three anions are disordered over two sites through a rotation along one of the F—P—F axes. The relative occupancies of the two sites for the F atoms are 0.643 (16):0.357 (16), 0.677 (10):0.323 (10) and 0.723 (13):0.277 (13). The crystal used was a racemic twin, with approximately equal twin components.

In the title compound, [Li₂(CF₃SO₂NSO₂CF₃)₂(CH₃CN)₂]_n, two Li⁺ cations reside on crystallographic inversion centers, each coordinated by six O atoms from bis(trifluoromethanesulfonyl)imide (TFSI⁻) anions. The third Li⁺ cation on a general position is four-coordinated by two anion O atoms and two N atoms from acetonitrile mol­ecules in a tetra­hedral geometry.