. 38. {111}

1 ( Van der Veen, 1913); 2: , , , , , , , . , -, , -

. . . (Fersman, Goldsch-midt, 1911) , (111) . , (, 1954; Frank, Puttick, Wilks, 1958, Frank, Puttick, 1958; Frank, Lang, 1959; , 1963; Lang, 1964; Patel, Agarwal, 1966; Varma, 1967 .).