History
Oxygen was 'discovered' in 1744. It had been produced before then, but it failed to be recognized as a distinct element. Joseph Priestley and Carl W Scheele both independently discovered it, however, Priestley is usually given credit for the discovery. Its name comes from the Greek word "oxys," meaning acid, and "genes," meaning forming, because scientists originally thought oxygen was present in all acids.

Things You Should Know About Oxygen
The melting point of oxygen is 54.36 K (or -218º C)
Its boiling point is 90.20 K (or -183º C)
State at room temperature: gas
Oxygen is a non-metal
Oxygen is in period 2, family 16 or 6A
Oxygen is highly reactive
Odorless, colorless, tasteless 

Uses
Oxygen is used for so many things. It makes an excellent rocket fuel when it is in its liquid form and combined with liquid hydrogen. It is also required by most living organisms, for breathing, and for most forms of combustion. It also plays an important role in the chemistries of other elements. Oxygen is the most abundant element in the earth's crust and in the human body. It also makes up about 50% of the sand, clay, limestone, and igneous rocks that make up the bulk of the earth's crust. Oxygen is the second most electronegative element, meaning it combines with pretty much any other element either directly or indirectly (see O2 and Ozone section below). Oxygen is found in a variety of compounds and it also exhibits primarily negative oxidation states, with the exception being the oxygen fluorine compound. 
Oxygen is the 3rd most widely used industrial chemical. Oxygen is used in peroxides, the most common of these being hydrogen peroxide. Potassium superoxide is used as one of the oxygen sources in rescue masks. 

O2 and Ozone
The tradition form of oxygen is O2, since because it is so electronegative it bonds to itself. But it can bond to itself 1 more time, forming O3, or ozone. Ozone can be made by passing electricity through dry O2. Ozone is considered a more powerful oxidizing agent than O2. Ozone protects the earth from UV radiation in the upper atmosphere, but it can be dangerous in the lower atmosphere because it is such a  powerful oxidation agent. Ozone is considered an air pollutant. 

Oxides
Oxide minerals include the natural compounds where oxygen is combined with 1 or more metals. A simple oxide is a compound of 1 metal and oxygen and are of several types with different X : O ratios, like XO1, X1O, X2O3, etc). Oxides are a group of minerals that are generally hard, dense, and refractory, however hydroxides tend to be lower in hardness and density. Oxides generally occur in igneous and metamorphic rocks. The most common of all oxides is SiO2, commonly called quartz. 

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Citations
Brown, Theodore L., and H. Eugene LeMay. "Oxygen." Chemistry: The        Central Science. Englewood Cliffs, NJ: Prentice-Hall, 1977. 632-36. Print.
​Klein, Cornelis, Cornelius S. Hurlbut, and James Dwight Dana.    "Oxides."Manual of Mineralogy: (after James D. Dana). New York: Wiley,    1985. 295. Print.
Thomas Jefferson National Accelerator Facility - Office of Science    Education. "The Element Oxygen." Jefferson Lab. Jefferson Lab, 11 Oct.    2015. Web. 11 Oct. 2015.