Compositional and structural control of tenebrescence

Abstract

The effect of various compositional substitutions on the colour of long-lived F-centres in the sodalite structure has been investigated by the synthesis and characterisation of several phases of the general composition A 8 [M 0 M 00 O 4 ] 6 [X,S] 2 . The visible-region absorption spectrum of the excited state, formed by 256 nm irradiation of the as-synthesised materials, shows a broad absorption whose position correlates with the dimensions of the sodalite cage occupied by the excited electron.

Luminescence and tenebrescence of natural sodalites: a chemical and structural study

“…An overview of other sodalite-group minerals (SGM) is given in Table 1. The metal site, M, typically contains mono-to divalent elements such as Ca, K, Li, Na, Sr, Mn and Zn (Deer et al 1996;Williams et al 2010;Hettmann et al 2012). The T site contains tetrahedrally coordinated elements such as Al, Si, B and Be (Kotel'nikov et al 2005;Williams et al 2010;Kaliwoda et al 2011).…”

“…These properties make photochromic minerals such as sodalite a key focus for material science, and their possible applications in industry have long been known (Medved 1954;Taylor et al 1970). Artificial luminescent minerals are promising for the development of new materials, which could be used as photochromic filters, information storage, special clothing or smart coatings (Armstrong and Weller 2006;Williams et al 2010).…”

“…The T site contains tetrahedrally coordinated elements such as Al, Si, B and Be (Kotel'nikov et al 2005;Williams et al 2010;Kaliwoda et al 2011). Considerable variations occur on the extra framework-site, X, where anions or molecules such as Cl − , Br − , I − , S 2− , SO 4 2− CO 3 2− and OH − are present (Fleet 2005;Kotel'nikov et al 2005;Bellatreccia et al 2009;Williams et al 2010;Balassone et al 2012;Hettmann et al 2012). Minerals of the sodalite group typically crystallize in SiO 2 -undersaturated and alkaline magmas and their associated hydrothermal systems (Hogarth and Griffin 1976;Deer et al 1996;Di Muro et al 2004;Krumrei et al 2007).…”

“…The metal site, M, typically contains mono-to divalent elements such as Ca, K, Li, Na, Sr, Mn and Zn (Deer et al 1996;Williams et al 2010;Hettmann et al 2012). The T site contains tetrahedrally coordinated elements such as Al, Si, B and Be (Kotel'nikov et al 2005;Williams et al 2010;Kaliwoda et al 2011). Considerable variations occur on the extra framework-site, X, where anions or molecules such as Cl − , Br − , I − , S 2− , SO 4 2− CO 3 2− and OH − are present (Fleet 2005;Kotel'nikov et al 2005;Bellatreccia et al 2009;Williams et al 2010;Balassone et al 2012;Hettmann et al 2012).…”

“…1). Each cage is a cubo-octahedral cavity containing a large anion such as Cl − , which is tetrahedrally coordinated by cations such as Na + Hassan and Grundy 1984;Williams et al 2010). Detailed chemical studies of SGM are given in e.g.…”