To investigate the nature of weak nonbonded selenium⊙⊙⊙ halogen interactions (Se⊙⊙⊙ X interactions; X= F, Cl, and Br), three types of model compounds [2-(CH2X) C6H4SeY (1-3), 3-(CH2X)-2-C10H6SeY (4-6), and 2-XC6H4CH2SeY (7-9); Y= CN, Cl, Br, SeAr, and Me] were synthesized, and their 77Se NMR spectroscopic behaviors were analyzed in CDCl3. The gradual upfield shifts of 77Se NMR absorptions observed for ...