Research Results For 'Caesium'

CAESIUM

Caesium is an alkaline metal discovered by Robert Bunsen in 1860, by spectral analysis, in the mineral water of Durkheim. It also occurs in the mineral pollux. Caesium is a soft metal closely resembling potassium, and is characterized by a spectrum containing two bright blue lines, along with others in the red, yellow and green.
Research Caesium

RUBIDIUM

Rubidium is a metallic element, symbol Rb. It is one of the alkali metals in group 1 of the periodic table. It was discovered spectroscopically in 1860 by the German chemist Robert Bunsen and the German physicist Gustav Kirchhoff, who named the element after the red lines in its spectrum. Metallic rubidium is silver-white and very soft. After caesium, it is the most active of the alkali metals. It tarnishes immediately upon exposure to air and ignites spontaneously to form rubidium oxide. It reacts violently with water. In general chemical behaviour, rubidium resembles the alkali metals, sodium and potassium. It is a widely distributed element, ranking 23d in order of abundance of the elements in the crust of the earth. It is not found in large deposits but occurs in small amounts in certain mineral waters and in many minerals usually associated with other alkali metals. It is also found in small quantities in tea, coffee, tobacco, and other plants, and trace quantities of the element may be required by living organisms.
Rubidium is used in making certain catalysts and in photoelectric cells. The rate of radioactive decay of the isotope rubidium-87 can be used in geologic age determination.
Research Rubidium

SECOND

The second is the basic SI unit of time, one-sixtieth of a minute. It is defined as the duration of 9,192,631, 770 cycles of regulation (periods of the radiation corresponding to the transition between two hyperfine levels of the ground state) of the caesium-133 isotope.

In mathematics, the second is a unit of angular measurement, equalling one-sixtieth of a minute, which in turn is one-sixtieth of a degree.

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