Signals Notebook: Column meanings in stoichiometry table MW,FM,EM and MF

MW is the sum of the average isotopic weights of the constituent elements in a molecule. 
FM is the sum of MW and the MWs associated salts and solvates (as defined using the salts and solvates feature in Signals Notebook).
EM is the sum of the most atomic weights of the most common isotope of the constituent elements in a molecule. 
MF displays the empirical formula of the compound appended with the MF of the associated salts and solvates (as defined using the salts and solvates feature in Signals Notebook).