Chemical elements
  Zinc
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      Zinc Fluoride
      Zinc Chloride
      Zinc Oxychlorides
      Zinc Bromide
      Zinc Iodide
      Zinc Hypochlorite
      Zinc Perchlorate
      Zinc Bromate
      Zinc Iodate
      Zinc Periodate
      Zinc Oxide
      Zinc Hydroxide
      Zincates
      Zinc Peroxide
      Zinc Sulphide
      Zinc Hydrosulphite
      Zinc Thiosulphate
      Zinc Sulphite
      Zinc Sulphate
      Zinc Dithionate
      Zinc Tetrathionate
      Zinc Pentathionate
      Zinc Selenide
      Zinc Selenites
      Zinc Selenate
      Zinc Telluride
      Zinc Tellurate
      Zinc Chromite
      Zinc Chromate
      Zinc Dichromate
      Zinc Molybdate
      Zinc Tungstate
      Zinc Nitride
      Zinc Azide
      Zinc Amide
      Zinc Ammoniate
      Zinc Nitrite
      Zinc Nitrate
      Basic Zinc Nitrates
      Zinc Phosphide
      Zinc Hydrophosphide
      Zinc Hypophosphite
      Zinc Phosphite
      Zinc Thiophosphite
      Zinc Orthophosphate
      Zinc Pyrophosphate
      Ammonium Zinc Orthophosphate
      Zinc Thiophosphates
      Zinc Arsenide
      Zinc Arsenite
      Zinc Arsenates
      Zinc Metantimonate
      Thioantimony Salts of Zinc
      Zinc Carbonate
      Zinc Thiocarbonate
      Zinc Cyanide
      Zinc Thiocyanate
      Zinc Silicide
      Zinc Silicates
      Zinc Borates
      Zinc Perborate
    PDB 12ca-1ai0
    PDB 1aiy-1b6z
    PDB 1b71-1bs8
    PDB 1bsk-1cao
    PDB 1caq-1ctt
    PDB 1ctu-1de6
    PDB 1def-1dy0
    PDB 1dy1-1ed6
    PDB 1ed8-1exk
    PDB 1eyf-1fj9
    PDB 1fjg-1g0e
    PDB 1g0f-1gkq
    PDB 1gkr-1ha5
    PDB 1hbm-1hso
    PDB 1hsz-1i6v
    PDB 1i73-1im5
    PDB 1iml-1jcv
    PDB 1jcz-1jy8
    PDB 1jyb-1kh4
    PDB 1kh5-1kys
    PDB 1kzo-1llm
    PDB 1llu-1m7j
    PDB 1m9j-1mwo
    PDB 1mwq-1ndv
    PDB 1ndw-1nyq
    PDB 1nyr-1os4
    PDB 1os9-1p9w
    PDB 1paa-1pud
    PDB 1pv8-1q9l
    PDB 1q9m-1qv6
    PDB 1qv7-1r6o
    PDB 1r79-1ro9
    PDB 1ror-1sfo
    PDB 1sg0-1t3k
    PDB 1t4k-1tkh
    PDB 1tkj-1u0l
    PDB 1u10-1ums
    PDB 1umt-1v67
    PDB 1v6g-1vrq
    PDB 1vs0-1wew
    PDB 1wfe-1wwf
    PDB 1wwg-1xb1
    PDB 1xb8-1xpz
    PDB 1xq0-1y5w
    PDB 1y5x-1ylk
    PDB 1ylo-1z8r
    PDB 1z93-1zkx
    PDB 1zl6-258l
    PDB 2a03-2afo
    PDB 2afs-2atq
    PDB 2au3-2bfz
    PDB 2bg2-2c3a
    PDB 2c4r-2cij
    PDB 2cim-2czr
    PDB 2d0w-2djw
    PDB 2dkc-2e1b
    PDB 2e1s-2eer
    PDB 2eex-2em4
    PDB 2em5-2eoj
    PDB 2eok-2erq
    PDB 2esf-2fa7
    PDB 2fac-2fpx
    PDB 2fqp-2g84
    PDB 2g87-2gvf
    PDB 2gvi-2han
    PDB 2hap-2huc
    PDB 2hue-2imc
    PDB 2imr-2j65
    PDB 2j6a-2jq5
    PDB 2jr7-2kfn
    PDB 2kft-2l75
    PDB 2lgv-2nx9
    PDB 2nxa-2oc8
    PDB 2occ-2osm
    PDB 2oso-2p53
    PDB 2p57-2pow
    PDB 2ppb-2q8j
    PDB 2qa1-2qp6
    PDB 2qpj-2r71
    PDB 2r74-2sod
    PDB 2srt-2v86
    PDB 2v87-2vp7
    PDB 2vpb-2vyo
    PDB 2vz5-2wey
    PDB 2wfq-2wx0
    PDB 2wx1-2xam
    PDB 2xan-2xr9
    PDB 2xrg-2ytd
    PDB 2yte-2z30
    PDB 2z3g-2zet
    PDB 2zh0-3a32
    PDB 3a36-3aoi
    PDB 3at1-3bk1
    PDB 3bk2-3byr
    PDB 3byw-3cia
    PDB 3ciz-3d08
    PDB 3d09-3dbu
    PDB 3dc3-3dp6
    PDB 3dpe-3e1w
    PDB 3e1z-3ebh
    PDB 3ebi-3epk
    PDB 3epl-3f28
    PDB 3f2b-3fhe
    PDB 3fhp-3ful
    PDB 3fum-3g9y
    PDB 3ga3-3gpu
    PDB 3gpx-3h2w
    PDB 3h3e-3hfy
    PDB 3hgz-3hsn
    PDB 3hso-3i8v
    PDB 3i9b-3ij6
    PDB 3ijf-3ixe
    PDB 3iz0-3k34
    PDB 3k35-3kiy
    PDB 3kj1-3kvt
    PDB 3kwa-3lat
    PDB 3lcn-3lrr
    PDB 3ls1-3m1n
    PDB 3m1v-3mek
    PDB 3men-3mru
    PDB 3ms0-3n63
    PDB 3n64-3nin
    PDB 3nis-3ny2
    PDB 3ny3-3ohc
    PDB 3ohd-3oyl
    PDB 3oym-3pih
    PDB 3pki-3r0d
    PDB 3rj7-3t74
    PDB 3t87-3u9g
    PDB 3ua7-3v24
    PDB 3v25-4agl
    PDB 4agm-4dih
    PDB 4dii-4efs
    PDB 4eg2-4fc8
    PDB 4fgm-6tli
    PDB 6tmn-9nse

Zinc Sulphate, ZnSO4






The heptahydrate, ZnSO4.7H2O, occurs naturally as goslarite, which crystallises in rhombic needles of hardness 2-2.5 and density 1.95-2.04. Shining rectangular tabular crystals, belonging to the rhombic system, of density 3.74 at 15° C., that are identical with natural zincosite, ZnSO4, are obtained by evaporating down a solution of zinc sulphate in sulphuric acid and carefully heating off the excess of acid. They soon become cloudy on exposure to air. Octahedral crystals of anhydrous zinc sulphate were prepared by heating hydrated zinc sulphates with ammonium sulphate. They dissolved slowly in cold water and rapidly in hot.

White amorphous anhydrous zinc sulphate is easily obtained by heating the hydrated sulphates. It may be heated to a dull red heat without decomposition, though it is converted into zinc oxide at higher temperatures.

The specific heat of anhydrous zinc sulphate is 0.174, and its density has been given variously from 3.400-3.681.

Zinc sulphide is formed by heating zinc sulphate either with an excess of sulphur or rapidly (to a white heat) with carbon. Zinc oxide is produced when a mixture of zinc sulphate and carbon is raised more slowly to dull redness, and metallic zinc if the temperature is raised to a bright red. Ammonia gas reduces the heated sulphate to a residue with the composition ZnO.ZnS.

One hundred parts of methyl alcohol dissolve 0.65 parts of anhydrous zinc sulphate, and the salt dissolves readily in water with the evolution of heat.

[ZnSO4]+400Aq. = ZnSO4.Aq. + 18.43 Cal.

At 20° C. 100 parts of water dissolve over 50 parts of ZnSO4.

Aqueous solutions of zinc sulphate are only slightly hydrolysed -0.03 per cent, in molar solution.

At temperatures below 39° C. the heptahydrate, ZnSO4.7H2O, usually crystallises from pure solutions of zinc sulphate made by dissolving the metal, sulphide, oxide, hydroxide, or carbonate in dilute sulphuric acid.

It is prepared industrially by carefully roasting zinc blende, extracting with water, and crystallising. Zinc sulphide ores are also treated with sulphuric acid, and the resulting sulphate, after treating with water and filtering, crystallised out. It is known commercially as white vitriol, and has a great variety of uses. It is used in dyeing and calico printing, for preparing pigments, varnishes, and various zinc compounds, and in disinfection, preserving wood or hides, flame proofing, and pharmacy.

It crystallises in rhombic prisms, isomorphous with Epsom salts.

Monoclinic crystals, isomorphous with FeSO4.7H2O, have been obtained by introducing a crystal of a monoclinic vitriol, like CoSO4.7H2O, into the supersaturated solution. They have been usually obtained as mixed crystals.

The density of white vitriol has been variously given from 1.931-1.976. The specific heat of the crystals is 0.328; they melt at about 50° C., effloresce slowly in the air and lose water more completely, eventually becoming anhydrous, as the temperature is raised.

[ZnSO4.7H2O] +400Aq. = ZnSO4.Aq. -4.26 Cal.

The solubility of ZnSO4.7H2O is -

Temperature, ° C0.115303539
Grm. ZnSO4 in 100 grm. Water41.9350.8861.9266.6170.05


At 39° C. the heptahydrate is transformed into the hexahydrate. This is important for the use of the Clark standard cell, which consists of the system mercury - mercurous sulphate - zinc sulphate crystals - zinc sulphate solution - zinc sulphate crystals - zinc amalgam (the mercurous sulphate being made into a paste with some zinc sulphate).

The solubility of the hexahydrate is -

Temperature, ° C.0.115303539
Grm. ZnSO4 in 100 grm. Water49.4857.1565.8267.9970.08


Both the hepta- and hexa-hydrate can exist for some time in a labile state outside their normal range of existence.

Monoclinic crystals of the hexahydrate, isomorphous with the corresponding magnesium salt, separate from solutions of zinc sulphate at temperatures above 39° C. Tetragonal crystals have been obtained by introducing a tetragonal crystal of NiSO4.6H2O into the supersaturated solution. The density of the monoclinic crystals is 2.056.

Pierre obtained a pentahydrate by evaporating a solution of zinc sulphate at 40°-50° C. till it began to crystallise, and cooling slowly to 35° C., and a salt of density 2.206 was obtained by boiling the finely powdered heptahydrate with alcohol of density 0.825.

The existences of a tetrahydrate and a trihydrate were deduced from the heats of hydration of zinc sulphates.

A dihydrate has been prepared by pouring a saturated solution of zinc sulphate into concentrated sulphuric acid and washing the precipitate with absolute alcohol. This salt had a density of 2.958. The heptahydrate is said to become the dihydrate in dry air, and, according to Etard, the same salt is obtained by evaporating a zinc sulphate solution at 120° C., or by heating a solution saturated at 15° C. in a closed vessel at 180° C.

When a solution of zinc sulphate is evaporated on the water-bath the residue is the monohydrate ZnSO4.H2O. It also deposits from a boiling saturated solution and crystallises from a solution of the heptahydrate in methyl alcohol. It has been prepared by heating heptahydrated zinc sulphate to 100° C. or 110° C.

The density of ZnSO4.H2O has been given as 3.076 and 3.289. Its specific heat is 0.202.

[ZnSO4.H2O]+400Aq. = ZnSO4.Aq.+9.95 Cal.

Rhombohedral crystals of ZnSO4.3½H2O have been reported. Lescoeur suggested that the number of hydrates had been overestimated.


Basic Sulphates of Zinc

The following basic sulphates have been reported: 8ZnO.SO3.16H2O; 8ZnO.SO3.7H2O; 8ZnO.SO3.6H2O; 8ZnO.SO3.2H2O; 8ZnO.SO3.H2O; 6ZnO.SO3.10H2O; 5ZnO.SO3; 4ZnO.SO3.7H2O; 4ZnO.SO3.6H2O; 4ZnO.SO3.5H2O; 4ZnO.SO3. 3H2O; (ZnOH)4SO4.

According to Lubkowskaia only 4ZnO.SO3.3H2O exists as a definite compound.

Ammoniates

Zinc sulphate absorbs ammonia gas in proportions depending upon the temperature. Zinc sulphate pentammoniate, ZnSO4.5NH4, decomposes at 19° C., the tetrammoniate at 98.5° C., and the triammoniate at 185° C. A hexammoniate exists at temperatures less than this range and a diammoniate at higher.

From a solution obtained by passing ammonia gas into a warm concentrated solution of zinc sulphate until it just cleared, the hydrated compounds ZnSO4.4NH4.4H2O, ZnSO4.4NH4.2H2O, and ZnSO4.2NH4.H2O were obtained. They lose ammonia and water progressively when heated - anhydrous zinc sulphate being ultimately left.

Deliquescent needles or tabular crystals of ZnSO4.4NH4.3H2O were obtained by treating a cooled solution of zinc sulphate in aqueous ammonia with ammonia gas.

In ammoniacal solutions of zinc sulphate there are probably complex ions containing NH4.

Acid Sulphates of Zinc

The acid sulphate SO4.ZnSO4.8H2O deposits in monoclinic crystals from solutions of zinc sulphate containing sulphuric acid. It dissolves sparingly in cold water, readily in hot, and loses water and sulphuric acid when heated.

Crystals of 3SO4.ZnSO4 have been separated by cooling the acid in the first chambers during the manufacture of sulphuric acid from zinc blende. When heated strongly they decompose into zinc sulphate and sulphuric acid.

Double Sulphates of Zinc

There is a large group of salts represented by the general formula M2SO4.RSO4.6H2O, where R is a divalent metal and M is NH4, thallium, or any alkali metal except lithium or sodium. The lithium and sodium salts either do not exist or have a different proportion of water of crystallisation. The salts with R = zinc can be prepared by dissolving the constituent simple salts in molecular proportions and crystallising.

Zinc sulphate also forms a series of double salts with the general formula ZnSO4.MSO4.14H2O, where M is magnesium, copper, manganese, iron (ferrous), or nickel.

The following salts have also been described: Na2SO4.ZnSO4.4H2O; KSO4.ZnSO4; KSO4.2ZnSO4; CuSO4.3ZnSO4.28H2O; (Zn, Fe)SO4.H2O, and (Zn, Cr)SO4.H2O.

Zinc sulphate is also a constituent of numerous complex salts.
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