Symbols
${\alpha }_p$	isobaric expansivity
δ	chemical shift
η	viscosity
ρ	density
σ	conductivity
$D$	self-diffusion
$F_{fv}$	free volume fraction
I	ionicity
$K_T$	isothermal compressibility
$M_w$	molecular weight
M	molar concentration
$N_A$	Avogadro number
$T_c$	crystallization temperature
$T_g$	glass transition
$T_m$	melting point
$V_h$	volume of holes
$V_{IonPair}$	molecular volume of the ion pair
$V_c$	volume of crystal
$V_{counterion}$	volume of the counterion
$V_i$	volume interstitial
$V_f$	free volume
$V_{ion}{A}^{-}$	volume molecular of anion
$V_{ion}{C}^{+}$	volume molecular of cation
$V_l$	volume of liquid
$Vm$	volume molar
$V_{occ}$	volume occupied
$V_w$	Van der Waals volume
$x$	molar fraction
General Abbreviations
APIL	Aprotic ionic liquid
API	Active Pharmaceutical Ingredients
COSMO-RS	Conductor-like Screening Model for Real Solvents
DFT	Density Functional Theory
E HB	hydrogen-bonding interaction energy
HB	hydrogen bond
EoS	equation of state
EPR	electron paramagnetic resonance
Eq	equation
FIR	Far-infrared
HSE-DD	Heisenberg spin exchange-dipole–dipole
IC	ionic cage
IL	ionic liquid
ImIL	imidazolium-based ionic liquid
IP	ion pair
MD	molecular dynamics
NP	nanoparticles
PALS	Positron Annihilation Lifetime Spectroscopy
PGSE	pulse-field-gradient spin–echo
PIL	Protic ionic liquid
PCM	polarizable continuum model
Ps	positroniums
pDTEMPONE	2,2,6,6-tetramethyl-4-oxopiperidine-1-oxyl
QENS	quasielastic neutron scattering
SL	Sanchez–Lacombe
SANS	Small angle neutron scattering
SAXS	Small angle X-ray scattering
VdW	Van der Waals
Ionic liquids acronym
[Ac]−	acetate
[BETI]−	bis(pentafluoroethylsulfonyl)imide)
[BF4]−	tetrafluoroborate
[B(hfip)4]−	1,1,1,3,3,3-hexafluoropropan-2-yl)oxy)borate
[BPy]+	N-butylpyridinium
[C2NH2]+	diethylammonium
[C2SO4]−	ethylsulfate
[C2eim]+	1,3-diethylimidazolium
[C2mim]+	1-ethyl-3-methylimidazolium
[C3mim]+	1-propyl-3-methylimidazolium
[C4mim]+	1-butyl-3-methylimidazolium
[C12mim]+	1-dodecyl-3-methylimidazolium
[C4mmim]+	1-butyl-2,3-dimethylimidazolium
[C4mpyr]+	N-butyl-N-methylpyrrolidinium
[C4NMe3]+	butyltrimethylammonium
[C5mpyr]+	N-pentyl-N-methylpyrrolidinium
[C5NEt3]+	pentyltriethylammonium
[C6mim]+	1-hexyl-3-methylimidazolium
[C8mim]+	1-octyl-3-methylimidazolium
[(C6H13)3P(C14H29)]+	trihexyltetradecylphosphonium
[CF3CO2]−	trifluoroacetate
[DCA]−	dicyanamide
[DEME]+	N,N-diethyl-N-methyl-N-(2-methoxyethyl) ammonium
[EtNH3]+	ethylammonium
[FAP]−	tris(perfluoroalkyl)trifluorophosphate
[FPI]−	bis[bis(pentafluoroethyl)phosphinyl]imide
[NTF2]−	bis(trifluoromethylsulfonyl)Imide
[MeSPh2]+	methyldiphenylsulfonium
[MeSO4]−	methylsulfate
[NO3]−	nitrate
[OcSO4]−	octyl sulfate
[OTF]−	triflate
[PF6]−	hexafluorophosphate
[SEt3]+	triethylsulfonium