Ankylosing spondylitis. Ankylosing spondylitis (AS) is a type of arthritis in which there is long term inflammation of the joints of the spine. Typically the joints where the spine joins the pelvis are also affected. Occasionally other joints such as the shoulders or hips are involved. Eye and bowel problems may also occur.
The allotropes of carbon. Three forms (or 'allotropes') of pure carbon are diamond, graphite and buckminster fullerene (or 'buckyballs'). In all three allotropes the carbon atoms are joined by strong covalent bonds but in such different arrangements that the properties of the allotropes are very different.he allotropes of carbon. Three forms (or 'allotropes') of pure carbon are diamond, graphite and buckminster fullerene (or 'buckyballs'). In all three allotropes the carbon atoms are joined by strong covalent bonds but in such different arrangements that the properties of the allotropes are very different.
1 Elements such as carbon, oxygen, phosphorus, tin and sulfur, display allotropy. 2  The different physical properties displayed by allotropes of an element are explained by the fact that the atoms are arranged into molecules or crystals in different ways. is a linear molecule while O 3 is a bent molecule. 2 and O 3 have different physical properties such as colour, odour, melting and boiling point, density and solubility. Some properties of the allotropes of oxygen are shown below: The two most common, naturally occurring allotropes of carbon are graphite and diamond.