Hypothetical chemical compound heat of formation ... can be used to determine whether a hypothetical compound is stable." However, "a negative formation enthalpy does not automatically imply the existence of a hypothetical compound." The method predicts that NaCl is stable but NeCl is not. It predicted XePtF based on the stability of OPtF. Hypothetical chemical compound A hypothetical chemical compound is a chemical compound that has been conceived of, but is not known to have been synthesized, observed, or isolated (identified or shown to exist). Some hypothetical compounds cannot form at all. Others might turn out to be highly unstable, decomposing, isomerizing, polymerizing,
Common minnow Hamilton. According to the selfish herd theory, a group forms as individuals try to reduce their domain of danger by approaching others and continuously moving toward the center of the group where the risk of predation is the lowest. As the theory predicts, common minnows increase their shoaling behavior in response to increased predation pressure. Common minnows can detect the predators’ presence and communicate with their shoalmates by a chemical signal that is detected by olfactory nerves. The chemical, named Schreckstoff after a German word meaning "fear substance" by Karl von Frisch who first described it, is contained in specialized