Crystalline inorganic berates comprise a structurally intriguing, technolog
ically important class of solid-state oxides. During the past 18 months, ne
w and unique examples have been synthesized; enhanced performance character
istics have been realized; and improved descriptions of physical properties
have been developed. Combined, these advances will likely increase the ove
rall scope of applicability for these materials. (C) 1999 Elsevier Science
Ltd. All rights reserved.