DEFINITION
Nickel- twenty-eighth element periodic table. Designation - Ni from the Latin "niccolum". Located in the fourth period, VIIIB group. Refers to metals. The nuclear charge is 28.
Like cobalt, nickel occurs in nature primarily in the form of compounds with arsenic or sulfur; such, for example, are the minerals kupfernickel NiAs, arsenic-nickel luster NiAsS, etc. Nickel is more common than cobalt [about 0.01% (wt.) of the earth's crust].
Nickel metal has a silvery color with a yellowish tint (Fig. 1), is very hard, polishes well, and is attracted by a magnet. It is characterized by high corrosion resistance - stable in the atmosphere, in water, in alkalis and a number of acids. Actively dissolves in nitric acid. The chemical resistance of nickel is due to its tendency to passivation - to the formation of oxide films on the surface that have a strong protective effect.
Rice. 1. Nickel. Appearance.
Atomic and molecular mass of nickel
DEFINITION
Relative molecular mass of the substance (M r) is a number showing how many times the mass of a given molecule is greater than 1/12 the mass of a carbon atom, and relative atomic mass element (A r)— how many times the average mass of atoms of a chemical element is greater than 1/12 the mass of a carbon atom.
Since in the free state nickel exists in the form of monatomic Ni molecules, the values of its atomic and molecular masses coincide. They are equal to 58.6934.
Nickel isotopes
It is known that in nature nickel can be found in the form of five stable isotopes 58 Ni, 60 Ni, 61 Ni, 62 Ni and 64 Ni. Their mass numbers are 58, 60, 61, 62 and 64, respectively. The nucleus of an atom of the nickel isotope 58 Ni contains twenty-eight protons and thirty neutrons, and the remaining isotopes differ from it only in the number of neutrons.
There are artificial unstable isotopes of nickel with mass numbers from 48 to 78, as well as eight meta-stable states, among which the longest-lived isotope 59 Ni with a half-life of 76 thousand years.
Nickel ions
The electronic formula demonstrating the orbital distribution of nickel electrons is as follows:
1s 2 2s 2 2p 6 3s 2 3p 6 3d 8 4s 2 .
As a result chemical interaction Nickel gives up its valence electrons, i.e. is their donor, and turns into a positively charged ion:
Ni 0 -2e → Ni 2+ ;
Ni 0 -3e → Ni 3+ .
Nickel molecule and atom
In the free state, nickel exists in the form of monoatomic Ni molecules. Here are some properties characterizing the nickel atom and molecule:
Nickel alloys
The main mass of nickel is used for the production of various alloys with iron, copper, zinc and other metals. Adding nickel to steel increases its toughness and resistance to corrosion.
Nickel-based alloys can be divided into heat-resistant (nimonic, inconel, hastell [over 60% nickel, 15-20% chromium and other metals]), magnetic (permalloy) and alloys with special properties (monel metal, nickel, constantan, invar, platinite).
Examples of problem solving
EXAMPLE 1
| Exercise | Write the reaction equations that can be used to carry out the following transformations: NiCl 2 → Ni → NiSO 4 → Ni(NO 3) 2 → Ni(OH) 2 → NiCl 2. Draw the equations for reactions occurring in solutions in ionic and abbreviated ionic forms. |
| Answer | By placing a metal more active than nickel in a solution of nickel (II) chloride, you can obtain nickel in free form (substitution reaction): NiCl 2 + Zn → Ni + ZnCl 2; Ni 2+ + Zn 0 → Ni 0 + Zn 2+ . Nickel dissolves in dilute sulfuric acid to form nickel(II) sulfate: Ni + H 2 SO 4 (dilute) → NiSO 4 + H 2; Ni 0 + 2H + → Ni 2+ + H 2 . Nickel(II) nitrate can be obtained by an exchange reaction: NiSO 4 + Ba(NO 3) 2 → Ni(NO 3) 2 + BaSO 4 ↓; SO 4 2- + Ba 2+ → BaSO 4 ↓. By treating nickel (II) nitrate with alkali, you can obtain nickel (II) hydroxide: Ni(NO 3) 2 + 2NaOH → Ni(OH) 2 ↓+ 2NaNO 3 ; Ni 2+ + 2OH - = Ni(OH) 2 ↓. Nickel(II) chloride can be obtained from nickel(II) hydroxide by neutralization reaction with hydrochloric acid: Ni(OH) 2 + 2HCl → NiCl 2 + 2H 2 O; OH - + H + = H 2 O. |
EXAMPLE 2
| Exercise | What mass of nickel(II) chloride can be obtained by heating 17.7 g of nickel and 12 liters of chlorine (n.s.)? What volume of 0.06 M solution can be prepared from this mass of salt? |
| Solution | Let's write the reaction equation: Ni + Cl 2 = NiCl 2. Let's find the number of moles of nickel ( molar mass- 59 g/mol) and chlorine that reacted using the data specified in the problem statement: n (Ni) = m (Ni) / M (Ni); n(Ni) = 17.7 / 59 = 0.3 mol. n (Cl 2) = V (Cl 2) / V m; n (Cl 2) = 12 / 22.4 = 0.54 mol. According to the equation of the problem n (Ni): n (Cl 2) = 1:1. This means that chlorine is in excess and all further calculations should be made using nickel. Let's find the amount of substance and the mass of nickel (II) chloride formed (molar mass 130 g/mol): n (Ni): n (NiCl 2) = 1:1; n (Ni) = n (NiCl 2) = 0.3 mol. m (NiCl 2) = n (NiCl 2) × M (NiCl 2); m (NiCl 2) = 0.3 × 130 = 39 g. Let's calculate the volume of a 0.06 M solution that can be obtained from 39 g of nickel (II) chloride: V(NiCl 2) = n (NiCl 2)/ c (NiCl 2); V (NiCl 2) = 0.3 / 0.06 = 0.5 l. |
| Answer | The mass of nickel (II) chloride is 39 g, the volume of a 0.06 M solution is 0.5 l (500 ml). |
" Complex connections nickel and their properties."
The work was compiled by 2nd year students of group 5202
Nikitin Dmitry and Sharkhemullin Emil.
Kazan 2014
Nickel complex compounds.
The binding of Nickel into complexes is an important process for analytical chemistry in the case of diagnostics and determination of the characteristic properties of substances and the element itself.
1.Complex compound of monovalent nickel
A limited number of them are known, while most are unstable and easily erode in the air; the compounds are colored predominantly red, obtained by the reduction of nickel (II) compounds such as - Nickel (II) oxide NiO, Nickel (II) hydroxide Ni(OH)2, Nickel (II) sulfide NiS). These include K2, Na2, K3, K2, - red.
2. Complex compounds of divalent nickel
These are the most important and stable nickel compounds.
The salts of strong acids formed by the divalent cation Ni2+ are almost all highly soluble in water, and their solutions show a slightly acidic reaction due to hydrolysis. Salts that are sparingly soluble are relatively weak acids, in particular derivatives of the CO32- and PO43- anions. The hydrated Ni·· ion will be colored bright green. The same color is characteristic of the crystalline salt hydrates formed by it. On the contrary, in the anhydrous state, individual complex salts are colored differently, and their colors do not always coincide with the intrinsic color of Ni2+ (yellow), but also depend on the nature of the anion.
A cation with a given valence (Ni 2+) forms a hexaammine complex 2+ and a diaquatetraammine complex 2+ with ammonia. These complexes with anions form blue or violet compounds, which greatly simplifies their diagnosis.
Aqueous solutions of nickel(II) salts contain hexaaquanickel(II) 2+ ion. When added to a solution containing these ions, ammonia solution Nickel(II) hydroxide, a green, gelatinous substance, precipitates. This precipitate dissolves when excess ammonia is added due to the formation of hexamminnickel(II) 2+ ions.
In some nickel ammonia there are 2+ and 2+ ions. Compounds derived from these and other nickel ammonia ions are readily soluble in water. The formation of these complexes explains the solubility in aqueous solution ammonia of many nickel compounds insoluble in pure water, such as its hydroxide and phosphate
Nickel is also very prone to the formation of intracomplex salts. These include salts in which a metal atom that has replaced hydrogen, for example nickel, is simultaneously linked by a coordination bond to another acidic residue. Intracomplex salts are often characterized by extremely low solubility. For this reason, they have recently become increasingly important in analytical chemistry. One of the most well-known representatives of this class of complex compounds is nickel dimethylglyoxime, which is widely used for the analytical determination of nickel.
Private representatives include hexamine nickel (II) chloride.
Hesaminnickel(II) chloride Cl2 is a light yellow or light blue hygroscopic powder that partially decomposes in air. Dissolves already in cold water. The thermal stability of the resulting complex ammonia is very high. Decomposes with water to release hydroxide
Ni:Cl2 =6H2O = Ni(OH)2 + 4NH4OH +2NH4Cl.
Oxygen has no effect on nickel ammonia solutions.
Nickel in this valence forms complexes with tetrahedral and planar square structures. For example, the tetrachloronicickelate(II)2− complex has a tetrahedral structure, while the tetracyanonickelate(II)2− complex has a planar square structure.
Nickel dimethylglyoxime/dimethylglyoximate.
The reaction of Ni 2+ ions with dimethylglyoxime (C4H8O2N2) is characteristic, leading to the formation of an intracomplex compound of pink-red nickel dimethylglyoximate, which is slightly soluble in water. Nickel dimethylglyoximate Ni(C 4 H 6 N 2 O 2) 2, a poorly soluble Ni(II) chelate complex in water, additionally stabilized due to intramolecular hydrogen bonds, giving a clear red color in an acidic environment, is used in analytical chemistry as qualitative reaction to nickel(II) ions.
Nickel dimethylglyoximate Ni(C 4 H 6 N 2 O 2) 2 can be obtained by adding dimethylglyoxime (Chugaev's reagent) and ammonia water (ammonia) to a solution of Ni(II) salt.
Reaction equation: NiSO4 + 2C4H8O2N2+ 2NH3 => Ni(C4H7O2N2)2 + (NH4)2 SO4.
Nickel sulfate is a crystalline substance of emerald green or turquoise color, soluble in water, eroded in air. This is a type of nickel salt.
Nickel sulfate is a highly toxic substance, so when working with it you must follow the rules for handling hazardous substances.
Chemical formula: NiSO4 7H2O.
Nickel sulfate is used in electroplating for nickel plating of products and metals.
And also - for the manufacture of batteries, catalysts, ferrites in the electronic and electrical industries, in metallurgy for the preparation of alloys. Nickel has found wide application in perfumery, fat and chemical industry as a reagent.
In the production of ceramics, nickel sulfate is used as a dye.
Safety requirements for nickel sulfate (nickel sulfate heptahydrate, nickel sulfate) GOST 4465-74.
Nickel(II) sulfate 7-hydrate is crystalline substance. When ingested into the human body, it has a carcinogenic and generally toxic effect. In contact with the skin and mucous membranes of the upper respiratory tract and eyes, the product is irritating and causes increased sensitivity to nickel.
When 7-aqueous nickel (II) sulfate is dissolved in water, a hydroaerosol is formed, which, in terms of the degree of impact on the body, belongs to substances of the 1st hazard class.
Extremely permissible concentration hydroaerosol of 7-aqueous nickel sulfate in terms of nickel in the air of the working area - 0.005 mg/m³.
The maximum permissible concentration of nickel ion in the water of reservoirs for sanitary use is 0.1 mg/dm³.
7-hydrate nickel sulfate cannot be neutralized or destroyed. The spilled product after dry and subsequent wet cleaning is disposed of in technological processes for the production or consumption of nickel sulfate.
IN air environment And wastewater Nickel sulfate does not form toxic substances.
Nickel (II) sulfate 7-water is non-flammable, fire- and explosion-proof.
Everyone working with nickel sulfate must be provided with special clothing, special shoes and other protective equipment. To protect the respiratory system, the ShB-1 “Lepestok” respirator should be used. To avoid contact with the skin of the hands, it is recommended to use protective paste IER-2 and lanolin-castor ointment. If nickel sulfate gets into your eyes, rinse them with copious amounts of water.
Production and laboratory premises in which work with 7-aqueous nickel sulfate is carried out must be equipped with supply and exhaust ventilation, and the equipment must be sealed.
Nikel- malleable and ductile metal. Nickel is ferromagnetic. In air it is stable. There is a protective film of NiO on the surface, which protects the metal from further oxidation.
WITH H2O and water vapor contained in the air, nickel doesn't respond either. Nickel practically does not interact with such acids as sulfuric, phosphoric, hydrofluoric and some others.
Interacts with HNO3:
3Ni + 8HNO 3 = 3Ni(NO 3) 2 + 2NO + 4H 2 O
WITH O2 reacts only at temperatures above 800° C.
Nickel oxide has basic properties. It exists in 2 modifications: low temperature (hexagonal lattice) and high temperature (cubic lattice).
It reacts with halogens and sulfur only at temperature to form NiHal 2 and NiS. When interacting with C, P, the following are formed: carbide Ni3C, phosphides - Ni 5 P 2, Ni 2 P, Ni 3 P.
With non-metals ( N 2) the reaction proceeds under optimal conditions.
There are salts that are soluble in water NiSO 4 , Ni(NO 3) 2 and many others that form crystalline hydrates NiSO 4 7H 2 O, Ni(NO 3) 2 6H 2 O.
Insoluble salts: phosphate Ni 3 (PO 4) 2 and silicate Ni 2 SiO 4.
If you add alkali to a solution of nickel(II) salt, a green precipitate of nickel hydroxide will form:
Ni(NO 3) 2 + 2NaOH = Ni(OH) 2 + 2NaNO 3.
Ni(OH)2 has weakly basic properties. When interacting with alkali:
2Ni(OH) 2 + 2NaOH + Br 2 = 2Ni(OH) 3 + 2NaBr.
Application of nickel and its compounds.
Nickel is most widely used in the production of stainless steel and alloys. Alloys that consume a lot of nickel include:
Monel metal ( Ni, Cu, Fe, Mn), widely used in chemical equipment, shipbuilding, for the manufacture of settling tanks and covers;
Nichrome and chromel ( Ni, Cr), used in the form of wire for rheostats, toasters, irons, heaters;
Invar ( Ni, Fe), used due to its very low expansion coefficient for the manufacture of pendulums in watches and measuring tapes;
Permalloy ( Ni, Fe), used in marine cable and power transmission technology due to its excellent magnetic susceptibility;
Nickel silver ( Ni, Cu, Zn) - for the manufacture of household utensils;
Alnico ( Ni, Co, Fe, Al) is a powerful magnetic material used to make small tools that have the properties of a permanent magnet.
Nickel coatings have long been used for decorative purposes and to protect many base metals from corrosion, although they are often replaced by chrome plating.
Long before the discovery of nickel, Saxon miners knew a mineral that was similar to copper ore and was used in glass making to color glass green. All attempts to obtain copper from it were unsuccessful, and therefore it received the name “kupfernickel”, which roughly means “Copper Devil” (cf. German Nickel - mischievous). This mineral (red nickel pyrite NiAs) was studied by the Swedish mineralogist and chemist Kronstedt in 1751. He managed to obtain green oxide and, by reducing the latter, a new metal called nickel.
Being in nature, receiving:
Nickel is quite common in nature - its content is earth's crust is 0.01% (mass.). In iron meteorites (up to 8%). In plants, on average, 5 * 10 -5 weight percent, in marine animals - 1.6 * 10 -4, in terrestrial animals - 1 * 10 -6, in the human body - 1 ... 2 * 10 -6
The bulk of nickel is obtained from garnierite and magnetic pyrites in several ways:
1. Silicate ore is reduced with coal dust in rotary tube kilns to iron-nickel pellets (5-8% Ni), which are then cleaned of sulfur, calcined and treated with an ammonia solution. After acidifying the solution, metal is obtained from it electrolytically.
2. Carbonyl method (Mond method). First, copper-nickel matte is obtained from sulfide ore, over which CO is passed under high pressure. Highly volatile tetracarbonylnickel is formed by thermal decomposition, which releases a particularly pure metal.
3. Aluminothermic method. Reduction of nickel from oxide ore with aluminum: 3NiO + 2Al = 3Ni +Al 2 O 3.
Physical properties:
Nickel metal has a silvery color with a yellowish tint, is very hard, tough and malleable, polishes well, and is attracted by a magnet. Density simple substance at no. 8.902 g/cm 3, melting point = 1726 K, boiling point = 3005 K.
Chemical properties:
At normal temperatures, nickel is characterized by high corrosion resistance - it is stable in air, water, alkalis, and a number of acids. Reacts with nitric acid, forming nickel(II) nitrate Ni(NO 3) 2 and the corresponding nitrogen oxide.
When heated, nickel reacts with many non-metals: halogens, sulfur, phosphorus, carbon. With atmospheric oxygen at 800°C, nickel forms the oxide NiO.
Nickel is capable of absorbing large volumes of hydrogen, resulting in the formation of solid solutions of hydrogen in nickel.
With carbon(II) monoxide, nickel easily forms the volatile and highly toxic carbonyl Ni(CO)4.
The most important connections:
In compounds, cobalt exhibits an oxidation state of +3, +2, 0.
Nickel(II) oxide, NiO- a solid substance from light to dark green or black in color. Basic properties prevail; it is reduced to metal by hydrogen and other reducing agents.
Nickel(II) hydroxide, Ni(OH) 2- green in color, slightly soluble in water and alkalis, good in many acids, basic properties predominate. When heated, it decomposes to form NiO.
Nickel(II) salts- usually obtained by reacting NiO or Ni(OH) 2 with various acids. Nickel salts soluble in water usually form crystalline hydrates, for example, NiSO 4 *7H 2 O, Ni(NO 3) 2 *6H 2 O. Insoluble nickel compounds include Ni 3 (PO 4) 2 phosphate and Ni 2 SiO 4 silicate. Crystalline hydrates and solutions are usually colored green, and anhydrous salts are yellow or brownish-yellow.
Nickel(II) complex compounds very numerous (number = 6). Their formation explains, for example, the dissolution of nickel oxide in an ammonia solution. Nickel dimethylglyoximate Ni(C 4 H 6 N 2 O 2) 2, giving a clear red color in acidic environment, is used as a qualitative reaction for nickel(II) ions.
Nickel(III) compounds- less typical. Known, for example oxide Ni 2 O 3 *H 2 O, a black substance, is obtained by the oxidation of nickel(II) hydroxide in an alkaline medium with hypochlorite or halogens:
2Ni(OH) 2 + 2NaOH + Br 2 = Ni 2 O 3 *H 2 O + 2NaBr + H 2 O
Strong oxidizing agent.
There are also nickel(III) complex compounds, for example, K 3.
Nickel carbonyl, Ni(CO) 4. Diamagnetic colorless liquid, very volatile and toxic. It hardens at -23°C, and when heated to 180-200°C, it decomposes into metallic nickel and carbon oxide (II). Ni(CO) 4 is slightly soluble in water, well in organic solvents, and does not react with dilute acids and alkalis.
Application:
Nickel is a component of many alloys - heat-resistant, resistance alloys (nichrome: 60% Ni + 40% Cr), jewelry (white gold, cupronickel), coins.
Nickel is also used for nickel plating - creating a corrosion-resistant coating on the surface of another metal. They are also used for the production of batteries, winding strings of musical instruments...
Nickel is one of the microelements necessary for normal development living organisms. He is known to take part in enzymatic reactions in animals and plants.
Nickel can cause allergies (contact dermatitis) to metals that come into contact with the skin (jewelry, watches, denim rivets). The European Union limits the nickel content in products that come into contact with human skin.
Rudagina Olga
HF Tyumen State University, 581gr., 2011
Sources: Wikipedia: http://ru.wikipedia.org/wiki/Ni, etc.,
Popular Library chemical elements. Nickel. http://n-t.ru/ri/ps/pb028.htm
Website of the Department of General and inorganic chemistry RKhTU im. DI. Mendeleev. Table D.I. Mendeleev: Nickel
