Citrate bridges between mineral platelets in bone

Significance Bone contains ∼2% wt citrate; however, its role in bone remains a much-debated question. We propose a new structure for bone mineral in which citrate in hydrated layers forms bridges between mineral platelets, which can explain a number of observations at odds with previous models. The incorporation of citrate between mineral platelets can explain the flat, plate-like morphology of bone mineral platelets and may be important in controlling the crystallinity of bone mineral, which in turn, is highly relevant to the mechanical properties of bone.