# How much Oxygen is in ζ-phase metallic Oxygen?

I am playing with a sci-fi idea of Oxygen storage for breathing. I wonder how do some compressed forms of Oxygen compare to human-breath-Oxygen (room temperature, room pressure) in terms of density.
Then, I've read a wikipedia article about solid Oxygen and it seems to explain that ζ-phase Oxygen is pretty high up on the density scale:
https://en.wikipedia.org/wiki/Solid_oxygen.
I hopelessly tried to convert 23.5 cm3/mol to a density measurement that I know (grams per cubic meter).
Also, I hopelessly tried to apply 96 GPa-pressurized Oxygen measurement to a density measure.
I am not a thermodynamics person :(
Will appreciate some extreme-density-Oxygen facts that I can play with :)

• First, density is not measured in grams per square meter. It is mass per unit volume. Here you are given how many cubic centimeters is occupied by one mole of oxygen. The mole can be converted into mass, and then you have the inverse of the density. Now, let me suggest that oxygen is a nearly ideal gas, and therefore one mole of O2 occupies roughly 22.4 liters at STP. Not surprisingly, you get about a ration of 1000 between the gas phase and a solid phase (a good general rule of thumb). – Jon Custer Dec 1 '15 at 17:05

One mole of oxygen is 32 grams. So the figure you cite tells you that 23.5 cm$^3$ of solid oxygen weighs 32 grams making the density about 1.36 g/cm$^3$ or 1360 kg/m$^3$.

For comparison the density of air is about 1.225 kg/m$^3$ and only 23% (by weight) of the air is oxygen. So the density of the oxygen in air is around 0.28 kg/m$^3$, which is a factor of nearly 5000 less than the solid oxygen.

BP  = 101.325 kPa
STP = 101.325 kPa,  0°C
NTP = 101.325 kPa, 20°C

Molar mass of oxygen = 31.9988 g                    [1]

Molar volume of gaseous  oxygen at STP = 22.41 L    [5]
Molar volume of liquid   oxygen at BP  = 28.04 cm³   -
Molar volume of metallic oxygen        = 23.5  cm³  [4]

Density of gaseous  oxygen at STP = 1,429  g/m³     [2]
Density of gaseous  oxygen at NTP = 1,331  g/m³     [6]
Density of liquid   oxygen at BP  = 1,141 kg/m³     [2]
Density of metallic oxygen        = 1,362 kg/m³  (calculated)

Ratio gas(STP):liquid:metallic = 1:798:953       (calculated)
Ratio gas(NTP):liquid:metallic = 1:857:1023      (calculated)

Note: Wiki [3] gives the gas:liquid O₂ compression ratio 1:861
- it is likely at different conditions than at NTP or STP
(possibly at around 25°C and BP)

Refrences:
----------
[1] http://webqc.org/molecular-weight-of-O2.html
[2] http://en.wikipedia.org/wiki/Oxygen
[3] http://en.wikipedia.org/wiki/Liquid_oxygen
[4] http://en.wikipedia.org/wiki/Solid_oxygen
[5] http://en.wikipedia.org/wiki/Molar_volume
[6] http://engineeringtoolbox.com/gas-density-d_158.html

• Impressive effort spent on such an old question! – Duncan Harris Apr 22 '16 at 3:33
• In fact I needed it for myself, so why not sharing it, when I already did the research :-) This thread shows up in Google near the top when searching for the density of metallic oxygen, so having all the relevant data and sources may be perhaps useful to some – Ivo Truxa Apr 22 '16 at 13:20
• Wow, I've made an impact on the internet! But I can't find a similarity between the two available answers, is one of you wrong or I just can't read thermodynamics? – DraxDomax Oct 15 '17 at 22:56