Editing Titanium (section)

=== Occurrence ===
Titanium is the ninth-most [[abundance of elements in Earth's crust|abundant]] element in [[Earth]]'s crust (0.63% by [[mass]])<ref name="Barksdale1968p732" /> and the seventh-most abundant metal. It is present as oxides in most [[igneous rock]]s, in [[sedimentary rock|sediments]] derived from them, in living things, and natural bodies of water.<ref name="EBC" /><ref name="LANL">{{RubberBible86th}}</ref> Of the 801 types of igneous rocks analyzed by the [[United States Geological Survey]], 784 contained titanium. Its proportion in soils is approximately 0.5–1.5%.<ref name="Barksdale1968p732" />

Common titanium-containing [[mineral]]s are [[anatase]], [[brookite]], [[ilmenite]], [[perovskite]], [[rutile]], and [[titanite]] (sphene).<ref name="Emsley2001p453">{{harvnb|Emsley|2001|p=453}}</ref> [[Akaogiite]] is an extremely rare mineral consisting of titanium dioxide. Of these minerals, only rutile and ilmenite have economic importance, yet even they are difficult to find in high concentrations. About 6.0 and 0.7 million tonnes of those minerals were mined in 2011, respectively.<ref name="USGS" /> Significant titanium-bearing ilmenite deposits exist in [[Australia]], [[Canada]], [[China]], [[India]], [[Mozambique]], [[New Zealand]], [[Norway]], [[Sierra Leone]], [[South Africa]], and [[Ukraine]].<ref name="Emsley2001p453" /> About 210,000 tonnes of titanium [[metal sponge]] were produced in 2020, mostly in China (110,000 t), Japan (50,000 t), Russia (33,000 t) and Kazakhstan (15,000 t). Total reserves of anatase, ilmenite, and rutile are estimated to exceed 2 billion tonnes.<ref name="USGS" />

{|class="wikitable floatleft"
|+ 2017 production of titanium minerals and slag<ref name="USGS" />
! Country !! thousand <br />tonnes !! % of total
|-
|[[China]]||3,830||33.1
|-
|[[Australia]]||1,513||13.1
|-
|[[Mozambique]]||1,070||9.3
|-
|[[Canada]]||1,030||8.9
|-
|[[South Africa]]||743||6.4
|-
|[[Kenya]]||562||4.9
|-
|[[India]]||510||4.4
|-
|[[Senegal]]||502||4.3
|-
|[[Ukraine]]||492||4.3
|-
|'''World'''||'''11,563'''||'''100'''
|}

The concentration of titanium is about 4 [[Molar concentration|picomolar]] in the ocean. At 100&nbsp;°C, the concentration of titanium in water is estimated to be less than 10<sup>−7</sup> M at pH 7. The identity of titanium species in aqueous solution remains unknown because of its low solubility and the lack of sensitive spectroscopic methods, although only the 4+ oxidation state is stable in air. No evidence exists for a biological role, although rare organisms are known to accumulate high concentrations of titanium.<ref>{{cite journal |doi= 10.1021/cr1002886 |pmid= 22074443 |title= Bioinorganic Chemistry of Titanium |journal= Chemical Reviews |volume= 112 |issue= 3 |pages= 1863–81 |year= 2012 |last1= Buettner |first1= K. M. |last2= Valentine |first2= A. M.}}</ref>

Titanium is contained in [[meteorite]]s, and it has been detected in the [[Sun]] and in [[stellar classification|M-type]] [[star]]s<ref name="LANL" /> (the coolest type) with a surface temperature of {{convert|3200|°C|°F}}.<ref name="Emsley2001p451">{{harvnb|Emsley|2001|p=451}}</ref> [[Rock (geology)|Rocks]] brought back from the [[Moon]] during the [[Apollo 17]] mission are composed of 12.1% TiO<sub>2</sub>.<ref name="LANL" /> Native titanium (pure metallic) is very rare.<ref>[http://www.mindat.org/min-7339.html Titanium]. Mindat</ref>