Liquid is a mixture of tetra ethoxy silane and polyethoxy siloxanes. Oxidation of organosilicon compounds, including siloxanes, gives silicon dioxide. Related to the siloxanes are the polysilazanes. These are mainly binary mixtures of hydrocarbons, fluorocarbons, hydrofluorocarbons, siloxanes and inorganic substances. However they have a strong tendency to polymerize into siloxanes. Other well known inorganic rings include borazine, SN, and the cyclic siloxanes. Chlorosilanes react with water to produce hydrogen chloride, giving siloxanes and eventually silicon dioxide. They are analogous to siloxanes, with -NH- replacing -O-. Practical and cost-effective technologies to remove siloxanes and other biogas contaminants are available. From this mixture, the cyclic siloxanes including D can be removed by distillation. Similar reactions are used industrially to convert cyclic siloxanes to linear polymers. In some cases, biogas contains siloxanes. Cyclic siloxanes have been detected in some species of aquatic life. The conversions of silyl halides, acetates, and ethers to siloxanes proceed via silanols. Cyclic siloxanes can be detected in some species of aquatic life.