a Direct-controlled Municipalities . b Sub-provincial cities as provincial capitals . c Separate state-planning cities . 1 Special Economic Zone Cities . 2 Coastal development cities .
3 Prefecture capital status established by Heilongjiang Province and not recognized by Ministry of Civil Affairs. Disputed by Oroqen Autonomous Banner , Hulunbuir, Inner Mongolia as part of it.
4 Only administers islands and waters in South China Sea and have no urban core comparable to typical cities in China.
5 The claimed province of Taiwan no longer have any internal division announced by Ministry of Civil Affairs of PRC, due to lack of actual jurisdiction. See Template:Administrative divisions of the Republic of China instead.
Metallic sodium is used in the manufacture of sodamide and esters, and in the preparation of organic compounds. The metal also may be used to modify alloys such as aluminum-silicon by improving their mechanical properties and fluidity. Sodium is used to descale (smooth the surface of) metals and to purify molten metals.
Sodium vapor lamps are highly efficient in producing light from electricity and are often used for street lighting in cities.
Sodium is used as a heat transfer agent; for example, liquid sodium is used to cool nuclear reactors.
Sodium chloride (table salt, NaCl) is vital for good nutrition. Sodium ions facilitate transmission of electrical signals in the nervous system and regulate the water balance between body cells and body fluids.