In 1803, after Hisinger had become an ironmaster, he returned to the mineral with Jöns Jacob Berzelius and isolated a new oxide which they named ceria after the dwarf planet Ceres, which had been discovered two years earlier. Ceria was simultaneously independently isolated in Germany by Martin Heinrich Klaproth. Between 1839 and 1843, ceria was shown to be a mixture of oxides by the Swedish surgeon and chemist Carl Gustaf Mosander, who lived in the same house as Berzelius: he separated out two other oxides which he named lanthana and didymia. He partially decomposed a sample of cerium nitrate by roasting it in air and then treating the resulting oxide with dilute nitric acid. That same year, Axel Erdmann, a student also at the Karolinska Institute, discovered lanthanum in a new mineral from Låven island located in a Norwegian fjord. Finally, Mosander explained his delay, saying that he had extracted a second element from cerium, and this he called didymium. Although he didnt realise it, didymium too was a mixture, and in 1885 it was separated into praseodymium and neodymium. Since lanthanums properties differed only slightly from those of cerium, and occurred along with it in its salts, he named it from the Ancient Greek λανθάνειν [lanthanein] (lit. to lie hidden). Relatively pure lanthanum metal was first isolated in 1923. Occurrence and production
Lanthanum is the third-most abundant of all the lanthanides, making up 39 mg/kg of the Earths crust, behind neodymium at 41.5 mg/kg and cerium at 66.5 mg/kg.
Ackerman syndrome or interstitial granulomatous dermatitis is a familial syndrome of fused molar roots with a single canal (taurodontism), hypotrichosis, full upper lip without a cupids bow, thickened and wide philtrum, and occasional juvenile glaucoma. It was described by James L. Ackerman, A. Leon Ackerman, and A. Bernard Ackerman. Signs and symptoms
Fused molar roots
Single root canal
Juvenile glaucoma
Sparse body hair
Distinct facial features: full upper lip, absence of cupids bow, thick philtrum
Syndactyly
Increased pigmentation of finger joints
Clinodactyly of fifth finger. Diagnosis
Treatment
References
External links

synd/133 at Who Named It?