File Name : schemes1_new.tif

Caption : scheme s1. orotic and l-tartaric acids

File Name : figs1_new.tif

Caption : fig. s1. manual liquid-assisted grinding of equimolar amounts of gaba, l-tartaric acid and water by mortar and pestle. experimental xrpd pattern shown black; theoretically calculated xrpd patterns for l-tartaric acid and hydrated salt of gaba with l-tartaric acid are put in blue and red, respectively.

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Caption : fig. s2. results of storage experiments of the hydrated molecular salt during 2 weeks. xrpd patterns of initial powder and the same sample after 5 weeks of storage in open vial are shown in black and magenta, respectively. there is no evidence of dehydration.

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Caption : fig. s3. intense manual grinding of the hydrated molecular salt of gaba with l-tartaric acid (black). theoretically calculated xrpd patterns of the hydrated salt shown red. stability of the compound is demonstrated. 

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Caption : fig. s4. a single crystal of the hydrated molecular salt of gaba with l-tartaric acid on storage on air during 1 month. no dehydration was observed (see results of phase analysis by xrpd). some visual turbidity of the crystal after several days of storage is common for any freshly prepared crystal. 

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Caption : fig. s5. results of dsc experiments with hydrated molecular salt of gaba with l-tartaric acid in an open crucible. first heating run: red line. second heating run: green line.

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Caption : fig. s6. results of the dsc experiments with the hydrated molecular salt of gaba with l-tartaric acid in a closed crucible. first heating run: red line. second heating run: green line.

File Name : figs7_new.tif

Caption : fig. s7. results of the tg experiments with the hydrated molecular salt of gaba with l-tartaric acid. total mass, % : red line. derivative of mass loss, %/min: green dashed  line. c-dta, k: black line.