LCH4

LCH4 is commonly used as shorthand for liquid methane, the liquid phase of methane CH4. The designation distinguishes a liquid from gaseous CH4 or solid CH4 in phase diagrams, laboratory notes, or propulsion literature. It is not a new chemical species; methane remains CH4 chemically, with L indicating state.

Physical properties: At standard pressure, methane liquefies at about 111.6 K (-161.6°C); it boils to gas above this temperature. It exhibits low viscosity and low surface tension, and a density around 0.42 g/cm3 in the liquid phase. Its critical point is about 190.6 K and 4.6 MPa. It is colorless and odorless in pure form and is non-polar.

Production and handling: Liquid methane is produced by cryogenic cooling of natural gas or methane streams; stored in double-walled, vacuum-insulated dewars at cryogenic temperatures. It is highly flammable and forms explosive mixtures with air; handling requires proper ventilation and avoidance of ignition sources. Contact with skin at cryogenic temperatures can cause severe frostbite.

Applications: LCH4 is widely used in rocket propulsion as LOX/LCH4, a clean-burning and efficient propellant; in research and cryogenics; in space exploration and potentially in energy storage. In modeling and simulations, LCH4 may be used to denote methane in the liquid state.