[1] It is non-stoichiometric in a range TiO0.7 to TiO1.3 and this is caused by vacancies of either Ti or O in the defect rock salt structure.

Careful annealing can cause ordering of the vacancies producing a monoclinic form which has 5 TiO units in the primitive cell that exhibits lower resistivity.

[2] A high temperature form with titanium atoms with trigonal prismatic coordination is also known.

[4][5] In 2017, TiO was claimed to be detected in an exoplanet atmosphere for the first time; a result which is still debated in the literature.

[6][7] Additionally, evidence has been obtained for the presence of the diatomic molecule TiO in the interstellar medium.