Table 2.

Calculated Raman symmetric stretching frequencies of single ${\text{AlF}}_4^{-}$, ${\text{AlF}}_5^{2-}$, ${\text{AlF}}_6^{3-}$ complex species and their neutral ion pairs with three different cations in comparison with experimental data and results of calculations reported in literature (the calculated values correspond to different conformations of the ionic pairs, see Figs. 2–4).

	Single forms (calc.)	Calculation			Experiment
		Li+	Na+[18]	K+	Li+	Na+	K+
${\text{AlF}}_4^{-}$	615	597, 628 (613–624)⁎	602, 620 (621)⁎	607, 619 (627)⁎	625 (612)⁎⁎	620 (622)&	618 (618)# (622)⁎⁎⁎
${\text{AlF}}_5^{2-}$	528	532, 537, 552 (528)⁎	547, 556 (553)⁎	551 (551)⁎	565	555 (555)&	551 (552)# (555)⁎⁎⁎
${\text{AlF}}_6^{3-}$	447	489, 555, 525 (496)⁎	457 (453)⁎	457, 466 (458)⁎	525 556)⁎⁎	520 (515)&	515 (510)# (515)⁎⁎⁎

^⁎Ref. [17].

^⁎⁎Ref. [10].

^⁎⁎⁎Ref. [11].

^#Ref. [8].

^&Ref. [24].