I was wondering if you knew the solubility rules for nitrates? I know alkali and ammonium nitrates are all water soluble, but what about other species like lead, Sr, Ba, etc.?
Answer:
I suspect that the reason you haven't found this data is because the answer is not as easy as "soluble" or "not soluble" (and I assume that we're talking about water as the solvent):
Pb(NO3)2 is soluble to 38 ppm in "cold" water and 130 ppm in "hot" water
Ba(NO3)2 is soluble to 5 ppm in "cold" water and 34.2 ppm in "hot" water
Sr(NO3)2 is soluble to 40 ppm in "cold" water and 100 ppm in "hot" water
where "cold" water is generally 3 degrees C and "hot" water is generally 95 degrees C.