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 skin cells called alarm substance cells and is released from an injured or killed minnow. The shoalmates can detect the chemical and respond to the increased risk of predation. The production and release of this alarm substance are altruistic because the sender of the signal, who does not directly benefit from the signal released upon its injury, has to pay the cost for the production and release of the chemical. In fact, the alarm substance cells decrease in number when the common minnows are in poor physical condition due to scarce food, indicating that there is metabolic cost for producing