Methyl cation, anion, and radical. Methyl cation. The methylium cation (CH3+) exists in the gas phase, but is otherwise not encountered. Some compounds are considered to be sources of the CH3+ cation, and this simplification is used pervasively in organic chemistry.
The square foot (plural square feet; abbreviated ft 2 or sq ft) is an imperial unit and U.S. customary unit (non-SI, non-metric) of area, used mainly in the United States and partially in Canada, United Kingdom, Hong Kong, Bangladesh, India and Pakistan. It is defined as the area of a square with sides of 1 foot.
The square foot is primarily used to indicate area in architecture, real estate and interior space plans. Square feet can be used to describe the area of any surface such as a floor-plan, wall or roof, whereas acres are used exclusively to describe the area of a parcel of land.