Efflorescence on calcareous objects in museums: crystallisation, phase characterisation and crystal structures of calcium acetate formate phases.
Efflorescence on calcareous objects in museums: crystallisation, phase characterisation and crystal structures of calcium acetate formate phases.
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博物馆中钙质物体的风化：醋酸钙甲酸相的结晶、相表征和晶体结构
DOI：
10.1039/c9dt03558c
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发表时间：
2019
影响因子：
4
通讯作者：
Dinnebier
中科院分区：
文献类型：
--
作者：
Müller;Eggert;Schleid;Dinnebier
在系统研究Ca（CH_3COO）_2-Ca（HCOO）_2-H_2O三元体系的过程中，观察到了两种固体乙酸甲酸钙的同成分结晶：迄今未知的Ca_3（CH_3COO）_4（HCOO）_2·4H_2O和表征不佳的Ca（CH_3COO）（HCOO）·H_2O。后者是在钙质物体上经常观察到的风化阶段，它也可以被确定为鸟蛋自然历史收藏中的腐蚀阶段。元素和热分析，以确定相组成和拉曼和红外光谱的存在下，乙酸根和甲酸根阴离子在这两种固体被证实。实验室X射线粉末衍射数据被用来解决晶体结构。Ca_3（CH_3COO）_4（HCOO）_2·4 H_2 O为四斜晶系，空间群为P41212，晶胞参数为a = 6.8655（1）<$，c = 45.5454（6）<$，而Ca（CH_3COO）（HCOO）·H_2 O为单斜晶系，空间群为P21/c，晶胞参数为a = 9.2729（1）<$，B = 6.8002（1）°，c = 11.2219（2）°，β = 121.232（1）°。两种晶体结构均以羧酸钙之字形链[Ca（μ2-RCOO）+]n（R = CH 3或H）为主。在Ca_3（CH_3COO）_4（HCOO）_2·4 H_2 O中，这些链完全由乙酸根阴离子组成，而在Ca（CH_3COO）（HCOO）·H_2 O中，只有甲酸根阴离子位于链中。钙阳离子的7-8倍配位球中的剩余位置被水分子和连接相邻链的额外羧酸根阴离子填充，这最终导致两种结构中的分层图案。
During the systematic investigation of the ternary system Ca(CH3COO)2–Ca(HCOO)2–H2O at room temperature, the congruent crystallisation of two solid calcium acetate formates was observed: the hitherto unknown Ca3(CH3COO)4(HCOO)2·4H2O and the poorly characterised Ca(CH3COO)(HCOO)·H2O. The latter is a frequently observed efflorescence phase found on calcareous objects and it could be also identified as a corrosion phase in a natural history collection of birds’ eggs. Elemental and thermal analyses were employed to determine the phase compositions and by Raman and IR spectroscopy the presence of acetate and formate anions in both solids was confirmed. Laboratory X-ray powder diffraction data were used to solve the crystal structures. Ca3(CH3COO)4(HCOO)2·4H2O crystallises in a primitive tetragonal unit cell with space group P41212 and lattice parameters of a = 6.8655(1) Å and c = 45.5454(6) Å, while Ca(CH3COO)(HCOO)·H2O crystallises in a primitive monoclinic unit cell with space group P21/c and lattice parameters of a = 9.2729(1) Å, b = 6.8002(1) Å, c = 11.2219(2) Å and β = 121.232(1)°. Calcium carboxylate zig-zag chains [Ca(μ2-RCOO)+]n (R = CH3 or H) are the main motif of both crystal structures. In Ca3(CH3COO)4(HCOO)2·4H2O these chains are exclusively composed of acetate anions, whereas in Ca(CH3COO)(HCOO)·H2O only formate anions are situated in the chains. The remaining places in the 7–8 fold coordination sphere of the calcium cations are filled by water molecules and additional carboxylate anions that interconnect neighbouring chains, which eventually leads to layered motifs in both structures.
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影响因子：
3.3
作者：
B. Mentzen;C. Comel
通讯作者：
B. Mentzen;C. Comel
希腊陶瓷上不寻常的风化
DOI：
--
发表时间：
1993
期刊：
影响因子：
--
作者：
G. Wheeler;M. Wypyski
通讯作者：
M. Wypyski
影响因子：
8.3
作者：
S. Bette;G. Eggert;Andrea Fischer;J. Stelzner;R. Dinnebier
通讯作者：
S. Bette;G. Eggert;Andrea Fischer;J. Stelzner;R. Dinnebier
DOI：
10.1039/jr9640004217
发表时间：
1964
期刊：
Journal of The Chemical Society (resumed)
影响因子：
--
作者：
E. Spinner
通讯作者：
E. Spinner
影响因子：
2.6
作者：
Apelblat, A;Manzurola, E
通讯作者：
Manzurola, E