Lithium hydroxide monohydrate, LiOH· H20, the "lithium hydrate" of commerce, was described crystallographically by V. von Lang2 ) as monoclinic prismatic, with the axial ratios a : b : c = 0.8184 : 1 : 0.3750 and β = 94°29'.

Each lithium is properly at the center of a tetrahedron of oxygens. Two such tetrahedra share an edge in a reflection plane. Upper and lower corners are shared with tetrahedra in cells above and below, resulting in unending chains of paired tetrahedra in the direction of the c-axis. These chains are linked sideways by hydroxyl bonding.

In figure 4 the structure is shown projected on the (010) plane. Small doubled circles represent lithiums, two being superposed in the projection due to the reflection plane. Similarly, large doubled circles indicate the two superposed oxygens on the two-fold axes. Single large circles represent oxygens in the reflection planes.

Ionic separations are indicated in table VII, the ions being labelled as in figure 4. Underlined entries correspond to distances within a single tetrahedron.  

References:

[1] PEPINSKY R. Crystal Structure of Lithium Hydroxide Monohydrate[J]. Zeitschrift Fur Kristallographie-Crystalline Materials, 1940. DOI:10.1524/zkri.1940.102.1.119.