In Minecraft bedrock edition (Xbox one) smooth varients of blocks are not craftable. For example to create smooth stone slabs you must have smooth stone but from my findings it is not craftable. This is also true for other smooth blocks like smooth sandstone and smooth quartz. This issue was mentioned in another bug report but was dismissed  because it was considered a "Feature Request". But this is a real bug cause it limits survival crafting like for armor stands you must have smooth stone slabs but they are not craftable