Methanides are a subset of carbides distinguished by their tendency to decompose in water producing methane. Three examples are aluminium carbide , magnesium carbide  and beryllium carbide .
Transition metal carbides are not saline: their reaction with water is very slow and is usually neglected. For example, depending on surface porosity, 5–30 atomic layers of titanium carbide are hydrolyzed, forming methane within 5 minutes at ambient conditions, following by saturation of the reaction.
Note that methanide in this context is a trivial historical name. According to the IUPAC systematic naming conventions, a compound such as NaCH would be termed a "methanide", although this compound is often called methylsodium. See Methyl group#Methyl anion for more information about the  anion.