Last Updated：2025/11/21
(physics) A radioactive isotope of calcium, ⁴⁵₂₀Ca, having twenty protons and twenty-five neutrons, and a half-life of 162.6 days; it is used as a tracer in studying calcium metabolism. As it decays it undergoes transformation (nuclear transmutation) via electron emission, also called negative beta decay (β−-decay), into scandium.
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calcium-45
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Source Word
calcium-45
Noun
uncountable
(physics)
A
radioactive
isotope
of
calcium,
⁴⁵₂₀Ca,
having
twenty
protons
and
twenty-five
neutrons,
and
a
half-life
of
162.6
days;
it
is
used
as
a
tracer
in
studying
calcium
metabolism.
As
it
decays
it
undergoes
transformation
(nuclear
transmutation)
via
electron
emission,
also
called
negative
beta
decay
(β−-decay),
into
scandium.
Japanese Meaning
カルシウム-45：放射性カルシウム同位体で、20個の陽子と25個の中性子を持つ。半減期は162.6日であり、カルシウム代謝の研究におけるトレーサーとして利用され、崩壊時には電子放出（β⁻崩壊）を経てスカンジウムに変わる。
Sense（1）
(physics)
A
radioactive
isotope
of
calcium,
⁴⁵₂₀Ca,
having
twenty
protons
and
twenty-five
neutrons,
and
a
half-life
of
162.6
days;
it
is
used
as
a
tracer
in
studying
calcium
metabolism.
As
it
decays
it
undergoes
transformation
(nuclear
transmutation)
via
electron
emission,
also
called
negative
beta
decay
(β−-decay),
into
scandium.
