Lithium diaqua­magnesium catena-borodiphosphate(V) monohydrate, LiMg(H2O)2[BP2O8]·H2O, at 173 K

The crystal structure of LiMg(H(2)O)(2)[BP(2)O(8)]·H(2)O consists of tubular structural units, built from tetra-hedral (∞) (1){[BP(2)O(8)](3-)} borophosphate ribbons and (LiO(4))(n) helices running along [001], which are inter-connected by MgO(4)(H(2)O)(2) octa-hedra, forming a three-dimensional network structure with one-dimensional channels along [001] in which the water mol-ecules are located. The water mol-ecule in the channel is significantly displaced by up to 0.3 Å from the special position 6b (..2) to a half-occupied general position. Mg, B and one Li atom all lie on twofold axes. Of the two Li positions, one is at a special position 6b (..2), while the other is at a general position; both are only half-occupied.