Zinc orthosilicate

Some oxide-type minerals have been found to luminesce when irradiated. A simple example is ruby (aluminium oxide with chromium activator), which emits bright-red light. The phosphors are incorporated into colour television screens to emit the colours blue (silver-activated zinc sulphide), green (manganese-activated zinc orthosilicate), and red (europium-activated yttrium vanadate). 

A third remarkable and unusual zinc mineral in die Franklin ore body is willemite, the fluorescent zinc orthosilicate which was first characterized in 1829 by Armand Levy, who named it for Willem I of the Netherlands (102). 

Silicates. Zinc orthosilicate Zn2Si04 Mn2 + can be produced by firing a mixture of ZnO, Si02, and MnC03 at 1200 °C for 2 h. Small quantities of MgF2 or ZnF2 accelerate the reaction [5.296]. 

A related study explores the use of OSi(OBu-t)3 chemistry, to prepare manganese-doped zinc orthosilicates, e.g. Zn2Si04 (willemite) which are used in electroluminescent... 

Mishra K C, Johnson K H, DeBoer B G, Berkowitz J K, Olsen J, Dale E A. First principles investigation of electronic structure and associated properties of zinc orthosilicate phosphors. J Lumin 1991 47 197-206. 

Zinc Silicate. Zinc orthosilicate. 04StZn2 mol wt 222.85. O 28.72%, Si 12.60%, Zn 58.68%. Zn2Si04. Occurs in nature as the mineral wiMemite. Prepd by heating the proper amounts of ZnO and Si02 at about 1200". 

Zn2Si04 ZINC ORTHOSILICATE (WILLEMITE) 1838 Zrl[g] ZIRCONIUM MONOIODIDE (GAS) 1873... 

The crystals are zinc orthosilicate. Artist Stuart Gray has carefully experimented with glaze compositions and firing temperatures to obtain the effect shown. 

Figure 13.39 shows a porcelain vessel in which the glaze displays beautiful needlelike crystal formations. The artist carefully formulated a glaze mixture of silica and zinc oxide, in addition to otho- oxides. He then fired the vessel with its glaze, carefully controlling the temperature, until only a few microscopic crystals of zinc oxide remained. These microscopic crystals formed the nuclei on which zinc orthosilicate crystallized. 

Such layers show UV fluorescence and the luminophore used determines the color the separated compounds appear as dark spots, usually at 254 nm. Silica gel F254 precoated plates available commercially containing zinc orthosilicate (green fluorescence at 254 nm) are among the most popular ones. The luminophores used in TLC offer a poor selectivity because the substances appear as colorless spots, but they are efficient in locating the separated compounds. 

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