Blood
About 98.5% of the oxygen in a sample of arterial blood in a healthy human breathing air at sea-level pressure is chemically combined with the hemoglobin. About 1.5% is physically dissolved in the other blood liquids and not connected to hemoglobin. The hemoglobin molecule is the primary transporter of oxygen in mammals and many other species (for exceptions, see below). Hemoglobin has an oxygen binding capacity between 1.36 and 1.40 ml O per gram hemoglobin, which increases the total blood oxygen capacity seventyfold, compared to if oxygen solely were carried by its solubility of 0.03 ml O per liter blood per mm Hg partial pressure of oxygen (about 100 mm Hg in arteries).
Liquid oxygen
Liquid oxygen has a pale blue color and is strongly paramagnetic: it can be suspended between the poles of a powerful horseshoe magnet. Liquid oxygen has a density of 1.141 g/cm (1.141 kg/L or 1141 kg/m), slightly denser than liquid water, and is cryogenic with a freezing point of and a boiling point of at 101.325 kPa (760 mmHg). Liquid oxygen has an expansion ratio of 1:861 under and , and because of this, it is used in some commercial and military aircraft as transportable source of breathing oxygen.