One kilogram was previously equal to the mass of the platinum-iridium bar, known as the International Prototype of the Kilogram, which was stored in Sèvres, France.
Other compounds came into use, but sodium fluoride is still widely used because of its unique physical characteristics.
Note that rounding errors may occur, so always check the results.
Fluoride can occur in drinking water naturally as a result of the geological composition of soils and bedrock.
Some materials have related density, for example water and beer have similar density in domestic usage.
The kilogram, or kilogramme, is the base unit for weight and is also a multiple of the.