<Tr> <Td_colspan="2"> Order and disorder in difluorides </Td> </Tr> <Tr> <Td> </Td> <Td> </Td> </Tr> <Tr> <Td> The strong and stable ionic fluorite structure adopted by calcium difluoride and many other difluorides </Td> <Td> Disordered structure of beryllium glass (sketch, two dimensions) </Td> </Tr> <P> Beryllium oxide, BeO, is a white refractory solid, which has the wurtzite crystal structure and a thermal conductivity as high as in some metals . BeO is amphoteric . Salts of beryllium can be produced by treating Be (OH) with acid . Beryllium sulfide, selenide and telluride are known, all having the zincblende structure . </P>

Where is the element beryllium found in nature