Although various hydrates have been reported over the years, and some suppliers even claim to stock them,[1] only the tetrahydrate and pentahydrate actually exist.

[2] What is called a hexahydrate, crystallized from a neutral solution, is probably a basic salt.

[4] The tetrahydrate, Th(NO3)4•4H2O is formed by crystallizing from a stronger nitric acid solution.

[3] To obtain the anhydrous thorium(IV) nitrate, thermal decomposition of Th(NO3)4·2N2O5 is required.

[8] Thorium nitrate can dissolve in several different organic solvents[7] including alcohols, ketones, esters and ethers.

[3] Thorium nitrate dissolved in water lowers it freezing point.

[7] A polymeric peroxynitrate is precipitated when hydrogen peroxide combines with thorium nitrate in solution with dilute nitric acid.

Each thorium atom is surrounded by three bidentate nitrate groups and three water molecules, bringing the coordination number to 11.

[7] Crystals the divalent metal thorium hexanitrate octahydrate have a monoclinic form with similar unit cell dimensions: β=97°, a=9.08 b=8.75-8 c=12.61-3.

[3] Thorium nitrate also crystallizes with other ligands and organic solvates including ethylene glycol diethyl ether, tri(n‐butyl)phosphate, butylamine, dimethylamine, and trimethylphosphine oxide.