Hydrogen bond
Hydrogen bonds can be intermolecular (occurring between separate molecules) or intramolecular (occurring among parts of the same molecule). Depending on the nature of the donor and acceptor atoms which constitute the bond, their geometry, and environment, the energy of a hydrogen bond can vary between 1 and 40 kcal/mol. This makes them somewhat stronger than a van der Waals interaction, and weaker than fully covalent or ionic bonds. This type of bond can occur in inorganic molecules such as water and in organic molecules like DNA and proteins.
Chalcogen bond
A chalcogen bond is an attractive interaction in the family of σ-hole interactions, along with hydrogen bonds and halogen bonds. This family of attractive interactions has been modeled as an electron donor interacting with the σ* orbital of a C-X bond (X= hydrogen, halogen, chalcogen, pnictogen, etc.). Electron density mapping is often invoked to visualize the electron density of the donor and an electrophilic region on the acceptor, referred to as a σ-hole. Chalcogen bonds, much like hydrogen and halogen bonds, have been invoked in various non-covalent interactions, such as protein folding, crystal engineering, self-assembly, catalysis, transport, sensing, templation, and drug design.