Luminescent compounds
 Polymorphous phosphorescent compounds of the formula MWO.sub.2 F.sub.4, wherein M is barium, strontium or lead, are prepared by the reaction of the appropriate metal tungstate with aqueous hydrofluoric acid. They have no electrons in the d orbital of the ground state, and therefore are useful in applications requiring phosphors with short primary decay times. 
General Electric Company
C C C C C
C01G C09K C01P C01P C09K
inventional inventional additional additional inventional
John F. Alok M.
Ackerman Srivastava