主要放射性元素一览
1．Cs (铯，cesium)
A soft, silvery-white ductile metal, liquid at room temperature, the most electropositive and alkaline of the elements, used in photoelectric cells and to catalyze hydrogenation of some organic compounds. Atomic number 55; atomic weight 132.905; melting point 28.5=C; boiling point 690=C; specific gravity 1.87; valence 1. 铯一种质地柔软的银白色韧性金属，室温时为液体，为最具正电性与碱性的元素，用作光电池和某些有机化合物氢化作用的催化剂。原子序数55；原子量132.905；熔点28.5=C；沸点=C；比重1.87；化合价1
2. Sr (锶，strontium)
A soft, silvery, easily oxidized metallic element that ignites spontaneously in air when finely divided. Strontium is used in pyrotechnic compounds and various alloys. Atomic number 38; atomic weight 87.62; melting point 769=C; boiling point 1,384=C; specific gravity 2.54; valence 2.
锶一种银色易氧化的软金属，被分割时能在空气中自燃。锶被用于烟火材料的复合物和各种合金。原子序数为38；原子量为87.62；熔点为769=C；沸点为1,384=C；比重为2.54；化合价为2
3. Ru(钌，ruthenium)
A hard white acid-resistant metallic element that is found in platinum ores and is used to harden platinum and palladium for jewelry and in alloys for nonmagnetic wear-resistant instrument pivots and electrical contacts. Atomic number 44; atomic weight 101.07; melting point 2,310=C; boiling point 3,900=C; specific gravity 12.41; valence 0, 1, 2, 3, 4, 5, 6, 7, 8.
钌一种坚硬的白色抗酸金属元素，在铂矿中可找到它，用于加固铂和钯以制成宝石和化合成非磁性的抗磨损的工具枢纽和电接触器。原子序数44；原子量101.07；熔点2,310=C；沸点3,900=C；比重12.41；原子价0,1,2,3,4,5,6,7,8
4. I (碘， iodine)
A lustrous, grayish-black, corrosive, poisonous halogen element having radioactive isotopes, especially I 131, used as a medical tracer and in thyroid disease diagnosis and therapy. Iodine compounds are used as germicides, antiseptics, and dyes. Atomic number 53; atomic weight 126.9044; melting point 113.5=C; boiling point 184.35=C; specific gravity (solid, at 20=C) 4.93; valence 1, 3, 5, 7.
碘一种有光泽的，灰黑色，具有腐蚀性的，有毒的卤元素，有放射性同位素，特别是碘131，被用作医疗上的显迹物和诊断、医治甲状腺疾病。碘化合物被用作杀菌剂、抗感染剂和染料。原子序数53；原子重量126.9044；熔点113.5=C；沸点184.35=C；比重（固体，在20=C时）4.93；化合价1，3，5，7 See: element
A liquid containing iodine dissolved in ethyl alcohol, used as an antiseptic for wounds.
碘酊；碘酒溶于酒精的碘的一种液体，用作防止伤口感染的药剂
5. Co(钴，cobalt)
A hard, brittle metallic element, found associated with nickel, silver, lead, copper,
and iron ores and resembling nickel and iron in appearance. It is used chiefly for magnetic alloys, high-temperature alloys, and in the form of its salts for blue glass and ceramic pigments. Atomic number 27; atomic weight 58.9332; melting point 1,495=C; boiling point 2,900=C; specific gravity 8.9; valence 2, 3.
钴一种硬而脆的金属元素，与镍、银、铅、铜和铁矿石一起存在，外表像镍和铁。它主要用于磁合金、高温合金、以盐的形式用于蓝色玻璃和陶瓷颜料。原子序数27；原子量58.9332；熔点1,495=C；沸点2,900=C；比重8.9；原子价2，3
6. Ba(钡，barium)
A soft, silvery-white alkaline-earth metal, used to deoxidize copper and in various alloys. Atomic number 56; atomic weight 137.34; melting point 725=C; boiling point 1,140=C; specific gravity 3.50; valence 2.
钡一种柔软，银白色的碱土金属，用来还原铜并用于各种合金。原子序数56；原子量137.34；熔点725=C；沸点1,140=C；比重3.50；化合价2
7. Ce(铈，cerium)
A lustrous, iron-gray, malleable metallic rare-earth element that occurs chiefly in the minerals monazite and bastnaesite, exists in four allotropic states, is a constituent of lighter flint alloys, and is used in various metallurgical and nuclear applications. Atomic number 58; atomic weight 140.12; melting point 795=C; boiling point 3,468=C; specific gravity 6.67 to 8.23; valence 3, 4.
铈一种有光泽、铁灰色、可延展的金属稀土元素，主要存在于独居石和氟碳铈矿中，以四种同素异形体存在，是轻燧石合金的成分，在冶金和核能工业上有多种应用。原子序数58；原子量140.12；熔点795=C；沸点3,468=C；比重6.67至8.23；比重6.67-8.23；化合价3,4
See: element
8. U(铀，uranium)
A heavy silvery-white metallic element, radioactive and toxic, easily oxidized, and having 14 known isotopes of which U 238 is the most abundant in nature. The element occurs in several minerals, including uraninite and carnotite, from which it is extracted and processed for use in research, nuclear fuels, and nuclear weapons. Atomic number 92; atomic weight 238.03; melting point 1,132=C; boiling point 3,818=C; specific gravity 18.95; valence 2, 3, 4, 5, 6.
铀银白色的重金属元素，有放射性并且有毒，容易被氧化。已知有14个同位素，其中U238是自然界含量最多的。这种元素存在如沥青铀矿和钒钾铀矿等几种矿中，并从中提炼和加工，主要用于研究，核燃料和核武器。原子序数为92；原子量为238.03；熔点为1,132=C；沸点3,818=C；比重18.95；化合价2，3，4，5，6
9. Pu(钚，plutonium)
A naturally radioactive, silvery, metallic transuranic element, occurring in uranium ores and produced artificially by neutron bombardment of uranium. Its longest-lived isotope is Pu 244 with a half-life of 76 million years. It is a radiological poison, specifically absorbed by bone marrow, and is used, especially the highly fissionable isotope Pu 239, as a reactor fuel and in nuclear weapons. Atomic number 94; melting point 640=C; boiling point 3,235=C; specific gravity 19.84; valence 3, 4, 5, 6.
钚一种天然地放射性银色超铀金属元素，存在于铀矿中，对铀元素进行中子轰
击而人工制成。其存在周期最长的同位素是半衰期为七千六百万年的钸244，它是一种核辐射毒素，特别是能被骨髓吸收。尤其是其极具可裂变性的同位素钸239，被用作一种核反应燃料并用在核武器中。原子序数94；熔点640=C；沸点3,235=C；比重19.84；化合价3, 4, 5, 6
10. Am(镅，americium)
A white metallic transuranic element of the actinide series, having isotopes with mass numbers from 237 to 246 and half-lives from 25 minutes to 7,950 years. Its longest-lived isotopes, Am 241 and Am 243, are alpha-ray emitters used as radiation sources in research. Atomic number 95; specific gravity 11.7; valence 3, 4, 5, 6.
镅锕系元素中的一种白色超铀金属元素，其同位素原子序数是从237到246，半衰期从25分钟到7,950年。其寿命最长的同位素镅241和镅243在研究中用作α射线辐射源。原子序数为95；比重11.7；原子价为3,4,5,6
主要放射性元素一览
1．Cs (铯，cesium)
A soft, silvery-white ductile metal, liquid at room temperature, the most electropositive and alkaline of the elements, used in photoelectric cells and to catalyze hydrogenation of some organic compounds. Atomic number 55; atomic weight 132.905; melting point 28.5=C; boiling point 690=C; specific gravity 1.87; valence 1. 铯一种质地柔软的银白色韧性金属，室温时为液体，为最具正电性与碱性的元素，用作光电池和某些有机化合物氢化作用的催化剂。原子序数55；原子量132.905；熔点28.5=C；沸点=C；比重1.87；化合价1
2. Sr (锶，strontium)
A soft, silvery, easily oxidized metallic element that ignites spontaneously in air when finely divided. Strontium is used in pyrotechnic compounds and various alloys. Atomic number 38; atomic weight 87.62; melting point 769=C; boiling point 1,384=C; specific gravity 2.54; valence 2.
锶一种银色易氧化的软金属，被分割时能在空气中自燃。锶被用于烟火材料的复合物和各种合金。原子序数为38；原子量为87.62；熔点为769=C；沸点为1,384=C；比重为2.54；化合价为2
3. Ru(钌，ruthenium)
A hard white acid-resistant metallic element that is found in platinum ores and is used to harden platinum and palladium for jewelry and in alloys for nonmagnetic wear-resistant instrument pivots and electrical contacts. Atomic number 44; atomic weight 101.07; melting point 2,310=C; boiling point 3,900=C; specific gravity 12.41; valence 0, 1, 2, 3, 4, 5, 6, 7, 8.
钌一种坚硬的白色抗酸金属元素，在铂矿中可找到它，用于加固铂和钯以制成宝石和化合成非磁性的抗磨损的工具枢纽和电接触器。原子序数44；原子量101.07；熔点2,310=C；沸点3,900=C；比重12.41；原子价0,1,2,3,4,5,6,7,8
4. I (碘， iodine)
A lustrous, grayish-black, corrosive, poisonous halogen element having radioactive isotopes, especially I 131, used as a medical tracer and in thyroid disease diagnosis and therapy. Iodine compounds are used as germicides, antiseptics, and dyes. Atomic number 53; atomic weight 126.9044; melting point 113.5=C; boiling point 184.35=C; specific gravity (solid, at 20=C) 4.93; valence 1, 3, 5, 7.
碘一种有光泽的，灰黑色，具有腐蚀性的，有毒的卤元素，有放射性同位素，特别是碘131，被用作医疗上的显迹物和诊断、医治甲状腺疾病。碘化合物被用作杀菌剂、抗感染剂和染料。原子序数53；原子重量126.9044；熔点113.5=C；沸点184.35=C；比重（固体，在20=C时）4.93；化合价1，3，5，7 See: element
A liquid containing iodine dissolved in ethyl alcohol, used as an antiseptic for wounds.
碘酊；碘酒溶于酒精的碘的一种液体，用作防止伤口感染的药剂
5. Co(钴，cobalt)
A hard, brittle metallic element, found associated with nickel, silver, lead, copper,
and iron ores and resembling nickel and iron in appearance. It is used chiefly for magnetic alloys, high-temperature alloys, and in the form of its salts for blue glass and ceramic pigments. Atomic number 27; atomic weight 58.9332; melting point 1,495=C; boiling point 2,900=C; specific gravity 8.9; valence 2, 3.
钴一种硬而脆的金属元素，与镍、银、铅、铜和铁矿石一起存在，外表像镍和铁。它主要用于磁合金、高温合金、以盐的形式用于蓝色玻璃和陶瓷颜料。原子序数27；原子量58.9332；熔点1,495=C；沸点2,900=C；比重8.9；原子价2，3
6. Ba(钡，barium)
A soft, silvery-white alkaline-earth metal, used to deoxidize copper and in various alloys. Atomic number 56; atomic weight 137.34; melting point 725=C; boiling point 1,140=C; specific gravity 3.50; valence 2.
钡一种柔软，银白色的碱土金属，用来还原铜并用于各种合金。原子序数56；原子量137.34；熔点725=C；沸点1,140=C；比重3.50；化合价2
7. Ce(铈，cerium)
A lustrous, iron-gray, malleable metallic rare-earth element that occurs chiefly in the minerals monazite and bastnaesite, exists in four allotropic states, is a constituent of lighter flint alloys, and is used in various metallurgical and nuclear applications. Atomic number 58; atomic weight 140.12; melting point 795=C; boiling point 3,468=C; specific gravity 6.67 to 8.23; valence 3, 4.
铈一种有光泽、铁灰色、可延展的金属稀土元素，主要存在于独居石和氟碳铈矿中，以四种同素异形体存在，是轻燧石合金的成分，在冶金和核能工业上有多种应用。原子序数58；原子量140.12；熔点795=C；沸点3,468=C；比重6.67至8.23；比重6.67-8.23；化合价3,4
See: element
8. U(铀，uranium)
A heavy silvery-white metallic element, radioactive and toxic, easily oxidized, and having 14 known isotopes of which U 238 is the most abundant in nature. The element occurs in several minerals, including uraninite and carnotite, from which it is extracted and processed for use in research, nuclear fuels, and nuclear weapons. Atomic number 92; atomic weight 238.03; melting point 1,132=C; boiling point 3,818=C; specific gravity 18.95; valence 2, 3, 4, 5, 6.
铀银白色的重金属元素，有放射性并且有毒，容易被氧化。已知有14个同位素，其中U238是自然界含量最多的。这种元素存在如沥青铀矿和钒钾铀矿等几种矿中，并从中提炼和加工，主要用于研究，核燃料和核武器。原子序数为92；原子量为238.03；熔点为1,132=C；沸点3,818=C；比重18.95；化合价2，3，4，5，6
9. Pu(钚，plutonium)
A naturally radioactive, silvery, metallic transuranic element, occurring in uranium ores and produced artificially by neutron bombardment of uranium. Its longest-lived isotope is Pu 244 with a half-life of 76 million years. It is a radiological poison, specifically absorbed by bone marrow, and is used, especially the highly fissionable isotope Pu 239, as a reactor fuel and in nuclear weapons. Atomic number 94; melting point 640=C; boiling point 3,235=C; specific gravity 19.84; valence 3, 4, 5, 6.
钚一种天然地放射性银色超铀金属元素，存在于铀矿中，对铀元素进行中子轰
击而人工制成。其存在周期最长的同位素是半衰期为七千六百万年的钸244，它是一种核辐射毒素，特别是能被骨髓吸收。尤其是其极具可裂变性的同位素钸239，被用作一种核反应燃料并用在核武器中。原子序数94；熔点640=C；沸点3,235=C；比重19.84；化合价3, 4, 5, 6
10. Am(镅，americium)
A white metallic transuranic element of the actinide series, having isotopes with mass numbers from 237 to 246 and half-lives from 25 minutes to 7,950 years. Its longest-lived isotopes, Am 241 and Am 243, are alpha-ray emitters used as radiation sources in research. Atomic number 95; specific gravity 11.7; valence 3, 4, 5, 6.
镅锕系元素中的一种白色超铀金属元素，其同位素原子序数是从237到246，半衰期从25分钟到7,950年。其寿命最长的同位素镅241和镅243在研究中用作α射线辐射源。原子序数为95；比重11.7；原子价为3,4,5,6