Some New Complex Silicate Phosphors Containing Calcium, Magnesium, and Beryllium

The simple silicates of Group II metals have long been known as phosphor bases. The only complex silicate containing two metals of Group II on which detailed information has been published is that containing zinc and beryllium. This paper establishes that under certain conditions of preparation CaO · MgO · 2 SiO 2 : Ti (diopside) is an efficient blue‐emitting silicate under cathode‐ray excitation. When cerium111 is used as an activator in this material, a highly efficient phosphor emitting mainly in the ultraviolet region is obtained. Manganese activation gives rise to a material emitting in two bands, orange and red, but the cathodoluminescent efficiency is poor. The compound 2 CaO · MgO · 2 SiO 2 (akermanite) activated by cerium III also emits in the ultraviolet region and is characterized by an extremely short decay time (about 10 −6 seconds). The 3 CaO · MgO · 2 SiO 2 compound (merwinite) is very similar, but is slightly less efficient. Neither of these two materials is effectively activated by titanium or manganese. Another complex silicate of unusual properties is CaO · BeO · SiO 2 : Mn (trimerite) which has a cathodoluminescent efficiency comparable to that of the zinc‐um silicates, with a long, moderately high‐level phosphorescence.