Cover illustration: A view of ammonium risedronate dihydrate, showing the atom-numbering scheme. Displacement ellipsoids are drawn at the 75% probability level. See Stahl, Oddershede, Preikschat, Fischer & Bennekou [Acta Cryst. (2006), C62, m112-m115].
The structure of RbBe4(BO3)3 is formed by  chains of [Be2BO4]− rings connected through O—B—O and O—Be—O—B—O bonds in the b and c directions, forming zeolite-type cages that contain the Rb+ cations.