browse words by letter
a
b
c
d
e
f
g
h
i
j
k
l
m
n
o
p
q
r
s
t
u
v
w
x
y
z
more about actinium
actinium |
3 definitions found From Webster's Revised Unabridged Dictionary (1913) [web1913]: Actinium \Ac*tin"i*um\, n. [Gr. ?, ?, ray.] (Chem.) A supposed metal, said by Phipson to be contained in commercial zinc; -- so called because certain of its compounds are darkened by exposure to light. From WordNet r 1.6 [wn]: actinium n : a radioactive element of the actinide series; found in uranium ores [syn: {Ac}, {atomic number 89}] From Elements database 20001107 [elements]: actinium Symbol: Ac Atomic number: 89 Atomic weight: (227) Silvery radioactive metallic element, belongs to group 3 of the periodic table. The most stable isotope, Ac-227, has a half-life of 217 years. Ac-228 (half-life of 6.13 hours) also occurs in nature. There are 22 other artificial isotopes, all radioactive and having very short half-lives. Chemistry similar to lanthanum. Used as a source of alpha particles. Discovered by A. Debierne in 1899.
more about actinium
This work is licensed under a
