Caldarchaeol is a membrane-spanning lipid found in hyperthermophilic archaea. Membranes made up of caldarchaeol are more stable since the hydrophobic chains are linked together, allowing the microorganisms to withstand high temperatures. It is also known as dibiphytanyldiglycerol tetraether. Two glycerol units are linked together by two strains which consist of two phytanes linked together to form a linear chain of 32 carbon atoms (40 carbons including methyl sidechains). Caldarchaeol is a membrane-spanning lipid found in hyperthermophilic archaea. Membranes made up of caldarchaeol are more stable since the hydrophobic chains are linked together, allowing the microorganisms to withstand high temperatures. It is also known as dibiphytanyldiglycerol tetraether. Two glycerol units are linked together by two strains which consist of two phytanes linked together to form a linear chain of 32 carbon atoms (40 carbons including methyl sidechains). The configuration of the macrocyclic tetraether has been determined by total synthesis of the C40-diol and comparison with a sample of obtained by degradation of natural tetraether. A synthesis of tetraether has also been carried out.