Table 1. Hydrogen-bond geometry (Å, °).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O2—H22⋯O11i	0.93 (4)	1.99 (4)	2.874 (3)	158 (4)
O2—H21⋯O21ii	0.72 (4)	2.23 (4)	2.940 (3)	168 (4)
O1—H12⋯O12i	0.84 (3)	1.86 (3)	2.695 (2)	174 (3)
O1—H11⋯O2	0.90 (4)	1.89 (4)	2.720 (2)	152 (3)

Symmetry codes: (i) ; (ii) .