Neutral buoyancy is a condition in which a physical body's average density is equal to the density of the fluid in which it is immersed. The buoyancy offsets the force of gravity that would otherwise cause the object to sink (if the body's density is bigger than the density of the fluid in which it is immersed) or rise (if it's smaller). An object that has neutral buoyancy will neither sink nor rise.
In scuba diving, the ability to maintain neutral buoyancy through controlled breathing accurate weighting and management of the buoyancy compensator is an important skill. A scuba diver maintains neutral buoyancy by continuous correction, usually by controlled breathing, as neutral buoyancy is an unstable condition for a compressible object in a liquid.
An inorganic nonaqueous solvent is a solvent other than water, that is not an organic compound. Common examples are liquid ammonia, liquid sulfur dioxide, sulfuryl chloride and sulfuryl chloride fluoride, phosphoryl chloride, dinitrogen tetroxide, antimony trichloride, bromine pentafluoride, hydrogen fluoride, pure sulfuric acid and other inorganic acids. These solvents are used in chemical research and industry for reactions that cannot occur in aqueous solutions or require a special environment.
The reactions of the compounds containing xenon are mostly conducted in hydrogen fluoride or bromine pentafluoride, which dissolve readily both xenon difluorides and its multiple derivatives, although sulfuric solvents are also used sometimes, in particular sulfuryl chloride fluoride for strong oxidants.