Table 2. Binding Energies Calculated (in kcal/mol) at the MP2/aug-cc-pVTZ(PP) and CCSD(T)/CBS Levels of Theories for HX···XH, C₆H₅X···XC₆H₅, and CH₃X···XCH₃ (Where X = F, Cl, Br, and I) Complexes at the Most Favorable X···X/X′ Distances.

		σ-hole binding features
complexes		interaction type	distance (Å)	EMP2/aug-cc-pVTZ(PP) (kcal/mol)	ECCSD(T)/CBS (kcal/mol)
hydrogen halide	HI···IH	σ-hole···σ-hole	4.06	–0.61	–0.65
	HI···BrH	di-σ-hole	3.91	–0.58	–0.56
	HI···ClH	di-σ-hole	3.82	–0.61	–0.56
	HI···FH	halogen bond	3.30	–1.14	–1.20
	HBr···BrH	σ-hole···σ-hole	3.76	–0.51	–0.46
	HBr···ClH	di-σ-hole	3.69	–0.49	–0.44
	HBr···FH	halogen bond	3.20	–0.74	–0.77
	HCl···ClH	σ-hole···σ-hole	3.61	–0.39	–0.35
	HCl···FH	halogen bond	3.21	–0.33	–0.37
	HF···FH	repulsive	a	a	a
halobenzene	C6H5I···IC6H5	σ-hole···σ-hole	3.90	–1.23	–1.30
	C6H5I···BrC6H5	di-σ-hole	3.75	–1.13	–1.13
	C6H5I···ClC6H5	di-σ-hole	3.68	–1.07	–1.06
	C6H5I···FC6H5	halogen bond	3.27	–1.26	–1.21
	C6H5Br···BrC6H5	σ-hole···σ-hole	3.61	–1.00	–0.95
	C6H5Br···ClC6H5	di-σ-hole	3.53	–0.90	–0.85
	C6H5Br···FC6H5	halogen bond	3.16	–0.93	–0.93
	C6H5Cl···ClC6H5	σ-hole···σ-hole	3.47	–0.75	–0.71
	C6H5Cl···FC6H5	halogen bond	3.14	–0.60	–0.59
	C6H5F···FC6H5	repulsive	a	a	a
halomethane	CH3I···ICH3	σ-hole···σ-hole	3.94	–1.07	–1.07
	CH3I···BrCH3	di-σ-hole	3.79	–0.94	–0.90
	CH3I···ClCH3	di-σ-hole	3.71	–0.86	–0.81
	CH3I···FCH3	halogen bond	3.28	–1.01	–1.00
	CH3Br···BrCH3	σ-hole···σ-hole	3.65	–0.76	–0.68
	CH3Br···ClCH3	di-σ-hole	3.58	–0.61	–0.55
	CH3Br···FCH3	halogen bond	3.20	–0.51	–0.52
	CH3Cl···ClCH3	σ-hole···σ-hole	3.54	–0.39	–0.35
	CH3Cl···FCH3	halogen bond	3.23	–0.06	–0.08
	CH3F···FCH3	repulsive	a	a	a

^aNo local minimum was observed in the corresponding potential energy surface (PES) curves for A–F···F–A complexes (Figure 4).