Sborgite is a sodium borate mineral with formula Na(B₅O₆(OH)₄)·3H₂O. The formula can be written as the oxide formulation, Na₂O.5B₂O₃.10H₂O. Sometimes called sodium pentaborate pentahydrate it contains the pentaborate anion, (B₅O₆(OH)₄)⁻.