泵业金属物理 化学特性
10贵金属元素的基本物理性质是什么?

费金属元素的基本物理化学性贡见表1.2。

11金、银有哪些物理性质?

金、银常见的形态分别为黄色和白色金属。不同纯度或不同颗粒度的金或银的单质的颜色不同，如流传已久的用试金石鉴定金的纯度的方法——条痕比色， 有“七青、八黄、九紫、十赤”的结论，意思是条痕呈青、黄、紫和赤色的金的含量分别为70%、80%、90%和纯金。随着金银颗粒度的减小，金或银可以呈现色彩丰富的各种颜色，而颗粒度小到纳米尺度时，无论是银或金所呈现的颜色均为黑色。
    金、银均为面心立方晶体结构，晶胞参数a分别为0. 4079nm 和0.4086nm,晶格和晶胞参数上的相似性决定了金和银特别容易形成互熔合金(固溶体)，而且金银合金中金和银的比例没有任何限制。
    金、银都具有极为良好的可锻性和延展性。金可压成

0. 001mm厚的箔，这样的金箔透明，所透过的光为绿色。金、银可拉成直径为0.001mm的细丝。
    金和银的导热、导电性能非常好。银的导电性胜过所有其他金属，金仅次于银和铜。金的蒸气压大大低于银。银的挥发性在高温下相当高，且在氧化气氛下比还原气氛下更高。这特性在火法冶金中必须重视。
12金有哪些化学性质?
    金的化学性质很稳定，是唯一在高温 下不与氧起反应的金属。1000C下将金置于氧气气氛中40h，没有检测到失重，在1075C、1125C和1250C下于空气中分别熔化金，经1h后损失金的质量分数分别为0.009%、0. 10%和0.26%，这部分为“挥发”损失，而非氧化损失。
    金具有宝贵的化学稳定性的原因可以从电离能进行探讨。决定金氧化态稳定性的因素很多，通常要考虑完整的能量循环，需要用到元素的电离能、电子亲和能和水合能等热力学数据。由于许多离子及化合物缺乏这方面的数据，有时只能用电离能作为般指 导性判据。TB族元素的电离能如表1.3所示。

从第一电离能数据可见，金具有宝贵的化学稳定性的原因在于Au具有很高的第一电离能。Au 的外层电子分布为4M54060，由于If和sd电子对核电荷的屏敞作用较弱，致使Au的6s电子受到较高的有效核电荷作用，不容易失去。  
    比较第二和第三电离能可以看出，Ag的第二电离能相对较

高，决定了它的主要氧化态是+1，而Au的第三电离能相对较低，导致Au易形成+3氧化态。由于Au的后几级电离能也相对较小，因此Au存在Au (V)氧化态。
    Cu、Ag和Au的电子亲和能的理论值分别为118.3kJ/mol、125. 7]kJ/mol和222.2 73kJ/mol。可以看出，Au的电子亲和能最高。
    金的相对较高的电子亲和能可与碘的电子亲和能(295.3kJ/mol)相比较，因此有人把Au看作拟卤素。已有的证据是化合物CsAu,可认为是CsAu-。基于Au有高的电离能和电子亲和能，可以预料Au具有高的电负性值。根据Pauling 的电负性标度，Au的电负性为2.4,是所有金属元素中最大的，比非金属元素P的电负性(为2.1)大，而与非金属元素C、S和I的电负性值(均为2.5)相近。渣浆泵厂家
    据上所述，Au的化合物的性质与Cu、Ag化合物的性质的不同之处远大于其相似之处。在许多情况下，把Au与周期表中同周期相邻元素铂和汞进行比较，比与同族的Cu、Ag比较更有价值。例如，存在着[AuCl2] 与HgCl2，[Au(PPhg)3J+与Au(PPh3)3以及[AuCl4]- 与[PtCl4]3- 的等电子配合物。

Physical and chemical characteristics of pump metal

What are the basic physical properties of precious metal elements?

See Table 1.2 for the basic physicochemical properties of the Fermi elements.

What are the physical properties of gold and silver?

The common forms of gold and silver are yellow and white metals respectively. The color of single gold or silver with different purity or particle size is different. For example, there is a long-standing method to identify the purity of gold with touchstone, i.e. streak color comparison. There is a conclusion that "seven cyan, eight yellow, nine purple and ten red" which means that the content of gold with stripes in cyan, yellow, purple and red is 70%, 80%, 90% and pure gold respectively. With the decrease of the particle size of gold and silver, gold or silver can present various colors with rich colors. When the particle size is small to nano scale, the color of silver or gold is black.

Gold and silver are both face centered cubic crystal structures, with cell parameters a of 0.4079nm and 0.4086nm, respectively. The similarity of lattice and cell parameters determines that gold and silver are particularly easy to form mutual melting alloy (solid solution), and there is no limit to the proportion of gold and silver in gold and silver alloy.

Gold and silver have excellent malleability and ductility. Gold can be pressed into

0. 001mm thick foil, so the gold foil is transparent and the light is green. Gold and silver can be drawn into 0.001mm diameter filaments.

Gold and silver have excellent thermal and electrical conductivity. Silver is more conductive than all other metals, and gold is second only to silver and copper. The vapor pressure of gold is much lower than that of silver. The volatility of silver is quite high at high temperature, and higher in oxidation atmosphere than in reduction atmosphere. This characteristic must be taken seriously in pyrometallurgy.

What are the chemical properties of gold?

Gold is the only metal that does not react with oxygen at high temperature. Gold was melted in air at 1075c, 1125c and 1250C for 40 hours at 1000C without any weight loss. After 1 hour, the mass fraction of gold lost was 0.009%, 0.10% and 0.26% respectively, which was "volatilization" loss rather than oxidation loss.

The reason why gold has precious chemical stability can be discussed from ionization energy. There are many factors that determine the stability of gold oxidation state. Generally, a complete energy cycle should be considered, and thermodynamic data such as ionization energy, electron affinity energy and hydration energy of elements should be used. Due to the lack of data in this field for many ions and compounds, sometimes only ionization energy can be used as a general guidance criterion. The ionization energy of TB group elements is shown in table 1.3.

It can be seen from the first ionization energy data that the reason for the valuable chemical stability of gold lies in the high first ionization energy of Au. The distribution of electrons in the outer layer of Au is 4m54060. Due to the weak shielding effect of if and SD electrons on the nuclear charge, the 6S electrons of Au are affected by higher effective nuclear charge, which is not easy to lose.

Comparing the second and third ionization energies, we can see that the second ionization energy of Ag is relatively higher

The main oxidation state of Au is + 1, but the third ionization energy of Au is relatively low, which leads to the formation of + 3 oxidation state. Since the latter ionization energy of Au is also relatively small, there is an oxidation state of Au (V).

The theoretical values of electron affinity of Cu, Ag and Au are 118.3kj/mol, 125.7] kJ / mol and 222.273kj/mol, respectively. It can be seen that AU has the highest electron affinity.

The relatively high electron affinity of gold can be compared with that of iodine (295.3kj / mol), so some people regard Au as a halogen like substance. The existing evidence is the compound csau, which can be considered as csau -. Based on the fact that AU has high ionization energy and electron affinity, it can be expected that AU has high electronegativity. According to Pauling's electronegativity scale, the electronegativity of Au is 2.4, which is the largest among all the metal elements, larger than that of P (2.1), and close to that of C, s and I (2.5). Slurry pump manufacturer

According to the above, the properties of Au compounds are much different from those of Cu and Ag compounds. In many cases, comparing Au with the neighboring elements of the same period in the periodic table, platinum and mercury, is more valuable than comparing Au with Cu and Ag of the same group. For example, there are isoelectronic complexes of [aucl2] with HgCl2, [Au (PPHG) 3j + with Au (PPh3) 3 and [AuCl4] - with [PtCl4] 3 -.