The notation  hydrated compound ânH2O , where n is the number of water molecules per formula unit of the salt, is commonly used to show that a salt is hydrated. The n is usually a low integer, though it is possible for fractional values to occur. For example, in a monohydrate n is one, and in a hexahydrate n is 6.
When does spring start? How you define the first day of spring depends on whether you follow the astronomical or meteorological seasons. This year, spring will take place between March 20 and June 21, if you use the astronomical method. But it starts slightly earlier, between March 1 and May 31, if you follow the meteorological calendar.
Beginning of meteorological spring 2018 March 1, 2018 in Northern Hemisphere Beginning of spring is a time when only the hardiest flowers like the crocus are in bloom. In meteorology for the Northern hemisphere, spring begins on March 01, 2018. It is also called the beginning of meteorological spring. The meteorological seasons are divided according to the calendar months. Spring months are March, April and May. Spring is one of the four conventional temperate seasons following winter and preceding summer. Spring is seen as a time of growth, renewal, of new life (both plant and animal) being born.