actiniumn.

Brit.

/akˈtɪnɪəm/, U.S.

/ækˈtɪniəm/

Origin: A borrowing from Greek, combined with an English element. Etymons: Greek ἀκτῖν- , ἀκτίς , -ium suffix.

Etymology: < ancient Greek ἀκτῖν-, ἀκτίς ray (see actino- comb. form) + -ium suffix. In sense 1 so called because of the action of light upon the supposed salts of the element; compare French actinium (1881 in this sense). In sense 2 after French actinium (A. Debierne 1900, in Comptes rendus hebd. de l'Acad. des Sci. 130 907), so called because of its radioactivity.

Chemistry.

†1. A supposed chemical element, a metal claimed to have been discovered in 1881 in association with zinc. Obsolete.

ΘΚΠ

the world > matter > chemistry > elements and compounds > metals > [noun] > unknown

didymium1842

hydrogenium1868

samarium1879

actinium1881

1881 T. L. Phipson in Chem. News 24 June 283/2 It was hinted that I was dealing with a new element (to be called ‘Actinium’); but the continuation of my experiments led me to believe that the phenomena..may probably be due to the presence of sulphide of barium and protoxide of iron.

1897 Science 12 Mar. 439/2 Of several supposed new elements the non-existence is more sure; such are metacerium, russium, jargonium, austrium, norwegium, actinium, idumium and masrium.

2. A radioactive metallic chemical element, atomic number 89, found in small quantities in uranium ores such as pitchblende. Symbol Ac.Actinium is the first member of the actinide series. The longest-lived isotope (actinium-227) has a half-life of about 22 years.

ΘΚΠ

the world > matter > chemistry > elements and compounds > metals > specific elements > actinium > [noun]

actinium1900

Ac1905

1900 Jrnl. Chem. Soc. 78 ii. 350 (title) Actinium: a new radio-active element.

1906 E. Rutherford in London, Edinb., & Dublin Philos. Mag. 6th Ser. 12 362 In order to obtain a homogeneous source of α rays, the active deposit of actinium was used.

1934 Sun (Baltimore) 11 Sept. 1/4 This small sample of protactinium is now producing a still rarer substance—actinium.

1958 R. D. Connor in O. R. Frisch Nucl. Handbk. iv. §24 Actinium..can be produced artificially by bombarding radium (Ra²²⁶) with neutrons.

1989 R. Pflaum Grand Obsession xviii. 314 Because research on the actinium family was not progressing fast enough to suit her, Marie..lent a hand.

1999 W. A. Harrison Elem. Electronic Struct. i. 10 In a series beginning with lanthanum, and one beginning with actinium, we successively fill the 4f- and 5f-atomic states.

Compounds

actinium series n. the series of isotopes produced by the radioactive decay of uranium-235 (and including actinium-227, originally thought to be the parent), each member resulting from the decay of the previous one.

ΚΠ

1906 New Internat. Encycl. XVI. 642b/2 The actinium series begins with actinium, which is precipitated by ammonia. It changes into actinium X, soluble in ammonia, without giving off rays.

1918 Science 3 May 442/1 A long-lived element of atomic weight ‘about 240’ which is the parent of the actinium series of elements.

1958 R. D. Connor in O. R. Frisch Nucl. Handbk. iv. §4 It gradually became clear that there existed three naturally-occurring families of radioactive substances, called the Uranium-Radium Series, the Thorium Series and the Actinium Series.

2009 H. Cember & T. E. Johnson Introd. Health Physics (ed. 4) iv. 116 Primordial radionuclides found in nature are not restricted to the thorium, uranium, and actinium series.

This entry has been updated (OED Third Edition, November 2010; most recently modified version published online December 2021).

单词	actinium
释义	actiniumn. Brit. /akˈtɪnɪəm/, U.S. /ækˈtɪniəm/ Origin: A borrowing from Greek, combined with an English element. Etymons: Greek ἀκτῖν- , ἀκτίς , -ium suffix. Etymology: < ancient Greek ἀκτῖν-, ἀκτίς ray (see actino- comb. form) + -ium suffix. In sense 1 so called because of the action of light upon the supposed salts of the element; compare French actinium (1881 in this sense). In sense 2 after French actinium (A. Debierne 1900, in Comptes rendus hebd. de l'Acad. des Sci. 130 907), so called because of its radioactivity. Chemistry. †1. A supposed chemical element, a metal claimed to have been discovered in 1881 in association with zinc. Obsolete. ΘΚΠ the world > matter > chemistry > elements and compounds > metals > [noun] > unknown didymium1842 hydrogenium1868 samarium1879 actinium1881 1881 T. L. Phipson in Chem. News 24 June 283/2 It was hinted that I was dealing with a new element (to be called ‘Actinium’); but the continuation of my experiments led me to believe that the phenomena..may probably be due to the presence of sulphide of barium and protoxide of iron. 1897 Science 12 Mar. 439/2 Of several supposed new elements the non-existence is more sure; such are metacerium, russium, jargonium, austrium, norwegium, actinium, idumium and masrium. 2. A radioactive metallic chemical element, atomic number 89, found in small quantities in uranium ores such as pitchblende. Symbol Ac.Actinium is the first member of the actinide series. The longest-lived isotope (actinium-227) has a half-life of about 22 years. ΘΚΠ the world > matter > chemistry > elements and compounds > metals > specific elements > actinium > [noun] actinium1900 Ac1905 1900 Jrnl. Chem. Soc. 78 ii. 350 (title) Actinium: a new radio-active element. 1906 E. Rutherford in London, Edinb., & Dublin Philos. Mag. 6th Ser. 12 362 In order to obtain a homogeneous source of α rays, the active deposit of actinium was used. 1934 Sun (Baltimore) 11 Sept. 1/4 This small sample of protactinium is now producing a still rarer substance—actinium. 1958 R. D. Connor in O. R. Frisch Nucl. Handbk. iv. §24 Actinium..can be produced artificially by bombarding radium (Ra²²⁶) with neutrons. 1989 R. Pflaum Grand Obsession xviii. 314 Because research on the actinium family was not progressing fast enough to suit her, Marie..lent a hand. 1999 W. A. Harrison Elem. Electronic Struct. i. 10 In a series beginning with lanthanum, and one beginning with actinium, we successively fill the 4f- and 5f-atomic states. Compounds actinium series n. the series of isotopes produced by the radioactive decay of uranium-235 (and including actinium-227, originally thought to be the parent), each member resulting from the decay of the previous one. ΚΠ 1906 New Internat. Encycl. XVI. 642b/2 The actinium series begins with actinium, which is precipitated by ammonia. It changes into actinium X, soluble in ammonia, without giving off rays. 1918 Science 3 May 442/1 A long-lived element of atomic weight ‘about 240’ which is the parent of the actinium series of elements. 1958 R. D. Connor in O. R. Frisch Nucl. Handbk. iv. §4 It gradually became clear that there existed three naturally-occurring families of radioactive substances, called the Uranium-Radium Series, the Thorium Series and the Actinium Series. 2009 H. Cember & T. E. Johnson Introd. Health Physics (ed. 4) iv. 116 Primordial radionuclides found in nature are not restricted to the thorium, uranium, and actinium series. This entry has been updated (OED Third Edition, November 2010; most recently modified version published online December 2021). < n.1881
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