TLV-TWA: chromium metal 0.5 mg/m3
(ACGIH and MSHA), 1 mg/m3 (OSHA);
Cr(II) and Cr(III) compounds 0.5 mg/m3
(ACGIH); Cr(VI) compounds, water soluble
and certain water insoluble, 0.05 mg/m3
(ACGIH).
物理描述:
Chromium is a very hard gray solid with a metallic luster. (NTP, 1992)
The silver soldered stainless steel wire corroded more than the cobalt-chromium type, & released more nickel & chromium than did the cobalt-chromium wires.
汽化热:
81.7 kcal/mol (at the boiling point)
表面张力:
1590 + or - 50 mN/m in vacuum at 1950 °C (Sessile drop method); 1700 + or - 50 mN/m in air at melting point (Dynam drop wt method); 1520 mN/m in air or Helium at 1800 °C (Sessile drop method)
The metabolism of Cr (VI) involves reduction by small molecules and enzyme systems to generate Cr (III) and reactive intermediates. During this process, free radicals can be generated, which is thought to induce damage of cellular components and cause toxicity of chromium. The metabolites bind to cellular constituents.
Chromium is absorbed from oral, inhalation, or dermal exposure and distributes to nearly all tissues, with the highest concentrations found in kidney and liver. Bone is also a major storage site and may contribute to long-term retention. Hexavalent chromium's similarity to sulfate and chromate allows it to be transported into cells via sulfate transport mechanisms. Inside the cell, hexavalent chromium is reduced first to pentavalent chromium, then to trivalent chromium by different pathways including ascorbate, glutathione, and nicotinamide adenine dinucleotide. Chromium is almost entirely excreted in the urine. (A12, L16)
IDENTIFICATION AND USE: Chromium elemental (Cr) is a steel-gray, lustrous metal. It is used in maufacturing of chrome-steel or chrome-nickel-steel alloys (stainless steel), nonferrous alloys, heat resistant bricks for refractory furnaces. This helps greatly increase strength, hardness and resistance of metals to abrasion, corrosion and oxidation. It is also used for chrome plating of other metals; leather tanning; as pigment and mordant and as a wood preservative. In medicine and laboratory research (51)Cr is used as a diagnostic aid. HUMAN EXPOSURE AND TOXICITY: Human exposure to Cr is increasing due to its use in Metal-on-metal (MOM) total hip arthroplasties. Metal-on-metal arthroplasty may lead to elevated blood Cr and cobalt (Co) levels. Cases of hypersensitivity to Cr and Co have been reported in such patients. Also both circulating-free-DNA and 8-hydroxydeoxyguanosine showed a tendency to increase in male patients. However, CoCr hip implants appear to be nongenotoxic. In electric welders exposed to Cr, a significant correlation was found between the frequency of sister chromatid exchanges and individual DNA strand breakage versus the concentration of Cr in the urine. ANIMAL STUDIES: Rats (25 total) were given 6 weekly iv injections of 0.18 mL of a 0.05% suspension of chromium powder; round cell sarcomas were found in 4 rats; 1 rat had hemangioma; 2 rats had papillary adenomas of the lung, and one rat showed extensive squamous cell carcinomatous changes. Metallic Cr was assayed for the ability to induce cell transformation (anchorage-independent growth) in Syrian hamster fibroblasts. Although chromium particles were phagocytized by cells, no significant increase in the number of cell foci growing in soft agar was observed. In male rats exposed to Cr fumes generated from powders of Cr metal by plasma flame sprayer developed significant increases in the frequencies of sister chromatid exchange and of chromosomal aberrations observed in peripheral blood lymphocytes, whereas chromosomal aberration frequencies in bone-marrow cells were unchanged. ECOTOXICITY STUDIES: Cr was toxic to naiad mollusks at 12.4 ppm. The greatest Cr toxicity risk to plants is posed in acidic sandy soil with low organic content.
Hexavalent chromium's carcinogenic effects are caused by its metabolites, pentavalent and trivalent chromium. The DNA damage may be caused by hydroxyl radicals produced during reoxidation of pentavalent chromium by hydrogen peroxide molecules present in the cell. Trivalent chromium may also form complexes with peptides, proteins, and DNA, resulting in DNA-protein crosslinks, DNA strand breaks, DNA-DNA interstrand crosslinks, chromium-DNA adducts, chromosomal aberrations and alterations in cellular signaling pathways. It has been shown to induce carcinogenesis by overstimulating cellular regulatory pathways and increasing peroxide levels by activating certain mitogen-activated protein kinases. It can also cause transcriptional repression by cross-linking histone deacetylase 1-DNA methyltransferase 1 complexes to CYP1A1 promoter chromatin, inhibiting histone modification. Chromium may increase its own toxicity by modifying metal regulatory transcription factor 1, causing the inhibition of zinc-induced metallothionein transcription. (A12, L16, A34, A35, A36)
来源:Toxin and Toxin Target Database (T3DB)
毒理性
致癌性证据
A4;不可归类为人类致癌物。/铬和Cr(III)无机化合物/
A4; Not classifiable as a human carcinogen. /Chromium and Cr(III) inorganic compounds/
Evaluation: There is inadequate evidence in humans for the carcinogenicity of metallic chromium and of chromium(III) compounds. There is inadequate evidence in experimental animals for the carcinogenicity of metallic chromium, barium chromate and chromium(III) compounds. Overall evaluation: Metallic chromium and chromium(III) compounds are not classifiable as to their carcinogenicity to humans (Group 3). /Metallic chromium and chromium(III) compounds/
来源:Hazardous Substances Data Bank (HSDB)
毒理性
致癌物分类
国际癌症研究机构致癌物:铬,金属形态
IARC Carcinogenic Agent:Chromium, metallic
来源:International Agency for Research on Cancer (IARC)
Chromium compounds are both absorbed by the lung and the gastrointestinal tract. Oral absorption of chromium compounds in humans can range between 0.5% and 10%, with the hexavalent (VI) chromium more easily absorbed than the trivalent (III) form. Absorption of chromium from the intestinal tract is low, ranging from less than 0.4% to 2.5% of the amount consumed. Vitamin C and the vitamin B niacin is reported to enhance chromium absorption. Most hexavalent Cr (VI) undergoes partial intragastric reduction to Cr (III) upon absorption, which is an action mainly mediated by sulfhydryl groups of amino acids. Cr (VI) readily penetrates cell membranes and chromium can be found in both erythrocytes and plasma after gastrointestinal absorption of Cr (IV). In comparison, the presence of chromium is limited to the plasma as Cr (III) displays poor cell membrane penetration. Once transported through the cell membrane, Cr (VI) is rapidly reduced to Cr (III), which subsequently binds to macromolecules or conjugate with proteins. Cr (III) may be bound to transferrin or other plasma proteins, or as complexes, such as glucose tolerance factor (GTF).
Absorbed chromium is excreted mainly in the urine, accounting for 80% of total excretion of chromium; small amounts are lost in hair, perspiration and bile. Chromium is excreted primarily in the urine by glomerular filtration or bound to a low molecular-weight organic transporter.
Absorbed chromium is distributed to all tissues of the body and its distribution in the body depends on the species, age, and chemical form. Circulating Cr (III) following oral or parenteral administration of different compounds can be taken up by tissues and accumulates in the liver, kidney, spleen, soft tissue, and bone.
来源:DrugBank
吸收、分配和排泄
清除
铬的排泄主要通过肾脏,范围从每天3到50微克。正常人体24小时尿液排泄率报告为0.22微克/天。
Excretion of chromium is via the kidneys ranges from 3 to 50 μg/day. The 24-hour urinary excretion rates for normal human subjects are reported to be 0.22 μg/day.
The objective of the Part II analysis was to evaluate animal and in vitro toxicology studies of CoCr particles with respect to their physicochemistry and dose relevance to metal-on-metal (MoM) implant patients as derived from Part I. In the various toxicology studies, physicochemical characteristics were infrequently considered and administered doses were orders of magnitude higher than what occurs in patients. Co was consistently shown to rapidly release from CoCr particles for distribution and elimination from the body. CoCr micron sized particles appear more biopersistent in vivo resulting in inflammatory responses that are not seen with similar mass concentrations of nanoparticles. We conclude, that in an attempt to obtain data for a complete risk assessment, future studies need to focus on physicochemical characteristics of nano and micron sized particles and on doses and dose metrics relevant to those generated in patients or in properly conducted hip simulator studies. /CoCr particles/
1.周国泰,化学危险品安全技术全书,化学工业出版社,1997 2.国家环保局有毒化学品管理办公室、北京化工研究院合编,化学品毒性法规环境数据手册,中国环境科学出版社.1992 3.Canadian Centre for Occupational Health and Safety,CHEMINFO Database.1998 4.Canadian Centre for Occupational Health and Safety, RTECS Database, 1989
Gas-phase reactions of iron(1-) and cobalt(1-) with simple thiols, sulfides, and disulfides by Fourier-transform mass spectrometry
作者:L. Sallans、K. R. Lane、B. S. Freiser
DOI:10.1021/ja00185a013
日期:1989.2
products, H-Fesup minus}}-SH and Fesup minus}}-SH. Some of the thermochemical data derived from this study include Ddegree}(Msup minus}}-S) > 103 kcal/mol and Ddegree}(Msup minus}}-SH) = 83 plus minus}9 kcal/mol. Finally, a brief survey of the reactivity of Vsup minus}}, Crsup minus}}, and Mosup minus}} with selected organosulfur compounds is also reported. 79 refs., 3 figs., 7 tabs
Crystallographic and magnetic properties of the hydrides (R = Y, Ce, Nd, Sm, Gd, Tb, and Dy)
作者:Xiu-Feng Han、Ren-Geng Xu、Xin-Hua Wang、H G Pan、T Miyazaki、E Baggio-Saitovitch、F M Yang、C P Cheng
DOI:10.1088/0953-8984/10/31/019
日期:1998.8.10
A systematic study of the structural and intrinsic magneticproperties of the hydrides R3Fe29-xCrxHy (R = Y, Ce, Nd, Sm, Gd, Tb, and Dy) has been performed. Hydrogenation lends to a relative volume expansion of the unit cell and a decrease in x-ray density for each compound. Anisotropic expansions mainly along the n- and b-axes rather than along the c-axis for all of the compounds upon hydrogenation
对氢化物 R3Fe29-xCrxHy(R = Y、Ce、Nd、Sm、Gd、Tb 和 Dy)的结构和内在磁特性进行了系统研究。氢化导致晶胞的相对体积膨胀和每种化合物的 X 射线密度降低。在氢化时,观察到所有化合物的各向异性膨胀主要沿 n 轴和 b 轴而不是沿 c 轴。R3Fe29-xCrx 和 R3Fe29-xCrxHy 的晶格常数和晶胞体积随着 R 原子序数从 Nd 到 Dy 的增加而减小,除了 Ce,反映了镧系元素收缩。对于每种化合物,氢化导致居里温度升高和室温下饱和磁化强度相应升高。加氢后减少0。在 4.2 K 时,平均 Fe 原子磁矩为 34 μ(B)/Fe,Y3Fe27.2Cr1.8 的各向异性场略有增加。 一级磁化过程 (FOMP) 发生在大约 1.5 T 的磁场中Nd3Fe24.5Cr4.5H5.0 和 TD3Fe27.0Cr2.0H2.8 在 4.2 K 时为 4.0 T,Gd3Fe28
Studies on the formation, structure and magnetic properties of Cr substituted Sm2(Fe, Cr)17Cx compounds
作者:Zhongmin Chen、G.C. Hadjipanayis
DOI:10.1016/s0304-8853(97)00079-6
日期:1997.7
Abstract The effects of Crsubstitution on the formation, structure and magnetic properties of Sm 2 (Fe, Cr) 17 C x compounds have been systematically studied on arc-melted and melt-spun samples using XRD, TEM and magnetic measurements. It has been found that Crsubstitution is an effective way to form the Sm 2 (Fe, Cr) 17 C x carbides. The minimum Cr amount for Sm 2 Fe 17− y Cr y C 2 to form an almost
摘要 使用XRD、TEM 和磁性测量,在电弧熔化和熔纺样品上系统地研究了Cr 取代对Sm 2 (Fe, Cr) 17 C x 化合物的形成、结构和磁性能的影响。已经发现,Cr取代是形成Sm 2 (Fe,Cr) 17 C x 碳化物的有效方式。Sm 2 Fe 17− y Cr y C 2 形成几乎单一的 2 : 17 相的最小 Cr 量约为 y = 2,而 Sm 2 Fe 15 Cr 2 C x 保留在单个 2 中的最大碳量: 17 结构在 x = 2 附近。磁性测量表明,Cr 取代的 Sm 2 (Fe, Cr) 17 C x 碳化物具有很强的单轴磁晶各向异性,在 Sm 2 Fe 15 Cr 2 C 2 和Sm 2 Fe 14 Cr 3 C 2 碳化物。然而,发现居里温度和磁化强度都随着 Cr 取代而降低。在通过熔纺技术生产的 Sm 2 (Fe, Cr) 17 C x 薄带中可以获得高矫顽力。在以
CeScSi- and CeFeSi-type structures in compounds derived from GdTiGe
were employed in investigations of the solid solutions based on GdTiGe compounds. These solid solutions have existence regions of the CeScSi-type phase, the CeFeSi-type phase and of their mixture. Gd 0.9 TiGe, Sm x Gd 1− x TiGe ( x =0–0.1, 0.9–1), GdSc x Ti 1− x Ge ( x =0–0.1), Y x Gd 1− x TiGe ( x =0–1), GdZr, Hf, V, Nb, Cr, Cu} 0.15 Ti 0.85 Ge, GdV, Mn} 0.3 Ti 0.7 Ge, GdTiGe 0.9 Si 0.1 form coherent
摘要 采用X射线相分析和金相分析等物理化学分析技术对基于GdTiGe化合物的固溶体进行研究。这些固溶体具有CeScSi型相、CeFeSi型相以及它们的混合物的存在区域。Gd 0.9 TiGe, Sm x Gd 1− x TiGe ( x =0–0.1, 0.9–1), GdSc x Ti 1− x Ge ( x =0–0.1), Y x Gd 1− x TiGe ( x =0– 1), GdZr, Hf, V, Nb, Cr, Cu} 0.15 Ti 0.85 Ge, GdV, Mn} 0.3 Ti 0.7 Ge, GdTiGe 0.9 Si 0.1 形成CeScSi型和CeFeSi型相的相干混合物, 而 GdTi 0.9 Ge 和固溶体 Sm x Gd 1- x TiGe ( x =0.2-0.9), GdSc x Ti 1- x Ge ( x =0.15-1), GdMo 0.15
Reaction of Thiols with N-Bonded Sulfenamide Complexes of Cobalt(III): Steric Effect and Reaction Pathway
作者:Margaret J. Sisley、Michael J. Ferguson、Robert B. Jordan
DOI:10.1021/ic048926l
日期:2005.1.1
The products and kinetics of the reaction of several thiols (RSH = 2-aminoethanethiol, cysteine, penicillamine, cysteine ethyl ester) with N-bonded sulfenamide complexes ([Co(en)(2)(NH(2)S(CH(2))(2)NH(2)](3+) (IA), [Co(en)(2)(NH(2)SCH(2)CH(CO(2)H)NH(2)](3+) (IC), [Co(en)(2)(NH(2)SC(CH(3))(2)CH(CO(2)H)NH(2)](3+) (IP)) have been studied. The reaction proceeds by nucleophilic attack at sulfur with cleavage