For mail deliveries via the United States Postal Service:

[Recipient’s first and last name]
Department of Chemistry
Yale University
P.O. Box 208107
New Haven, CT 06520-8107

For deliveries via all other couriers (FedEx, UPS, DHL, etc.):

[Recipient’s first and last name]
Yale University Chemistry Department
Chemical Safety Building
Room 101
295 Prospect Street
New Haven, CT 06511