Cleve, Per

Chemiluminescence, 403 Citric acid method, 396, 400 Cleve, Per Theodor, 8 Closed-packed fullerenes, 136 Cluster, 138 beam, 97... 

In 1904 Ramsay received the Nobel Prize in chemistry in recognition of his services in the discovery of the inert gaseous elements in air, and his determination of their place in the periodic system, becoming the first British recipient of this award, see also Argon Cleve, Per Theodor Strutt, John (Lord Rayleigh). 

Thulium metal is soft, ductile, and malleable and can be cut with a knife. It tarnishes when in contact with air and reacts with water. Thuhum has very few commercial uses. Radioactive thulium can be utihzed as a power source for portable x-ray machines and is produced by irradiating the element in a nuclear reactor. Thulium may also be utihzed to make magnetic ceramic materials found in microwave equipment, see also Cleve, Per Theodore. 

Cleve, Per Teodor (1840-1905) Swedish chemist who worked on the rare earths and decided that the element didymium. 

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