5 -phosphate trihydrate, crystal structure

Many drugs and excipients (cephalexin monohydrate, quinidine sulfate dihydrate, ampicillin trihydrate, codeine sulfate trihydrate, morphine sulfate dihydrate, dicalcium phosphate trihydrate, raffinose pentahy-drate, lactose monohydrate) utilize water as an integral part of their crystal structure. Solids that form specific crystal hydrates tend to sorb relatively small amounts of water to their external surface below a characteristic relative humidity, when initially dried to an anhydrous... 

These crystal-structure analyses are concerned with the following molecules o-D-glucopyranose monohydrate/ D-xylopyranose/ methyl yS-D-xylopyranoside, di-jS-n-fructopyranose-strontium chloride trihydrate, cellobiose (independent determination), D-glucaric acid, D-galactonic acid, methyl a-D-lyxofuranoside, /3-D-lyxopyranose, methyl 3,4,6-tri-0 - acetyl - 2 - (chloromercuri) - 2 - deoxy - j3 - d - glucopyranoside, D-glu-copyranosyl (potassium sodium phosphate) tetrahydrate," and methyl 6-bromo-6-deoxy-a-D-galactopyranoside. ... 

When crystallized from solution, the phosphates of the heavier rare earths contain two water molecules. The dihydrate is found in nature, as the minerals weinschenkite and churchite (Strunz, 1942 ClaringsbuU and Hey, 1953), which have monoclinic structure. According to Hezel and Ross (1967), the heavier rare earths also have a tetragonal trihydrate with a structure similar to that of zircon where the water molecules are uncoordinated. 

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