Last updated

The oxalatonickelates are a class of compounds that contain nickel complexed by oxalate groups. They form a series of double salts, and include clusters with multiple nickel atoms. Since oxalate functions as a bidentate ligand it can satisfy two coordinate positions around the nickel atom, or it can bridge two nickel atoms together.

The shape around the nickel atom is octahedral for diaquabis(oxalato)nickelate. The colour of this is green due to the Ni(–O–)6 chromophore. The absorption in infrared is at 8,300 9,060 13,400, 15,260, and 26,160  cm−1. [1] The ligand field parameters are 10 Dq=8800 cm−1 and B=1000 cm−1. [1]

formulanameother namesstructurecolour or decompositionCAS Numberreferences
[(C2O4)2Ni]2−bis(oxalato)nickelate (2−) [2]
Li2[(C2O4)2Ni]•6H2Odilithium bis(oxalato)nickelate (2−)dehydrate 80° decompose 345°112678-94-1 [3]
Na2[(C2O4)2Ni]•3H2Odisodium bis(oxalato)nickelate (2−)dehydrates at 85°, decompose over 320°107996-66-5 [4] [5]
[NH4]2[(C2O4)2Ni]•3H2Odiammonium bis(oxalato)nickelate (2−)dehydrate 180-262° deaminate 262-338 °C108559-31-5 [4] [6]
K2[(C2O4)2Ni•2H2O]•4H2Odipotassium trans-diaquabis(oxalato-O,O')nickelate(II)-water (1/4)potassium bis oxalate nickel(II) tetrahydrate monoclinic a=8.647 b=6.627 c=12.118 β=101.58° V=680.3 Z=2 density=2.05 / 2.04green14244-63-4 [7] [8] [9] [10]
Co[(C2O4)2Ni]•5H2Ocobalt(II)bis(oxalato)nickelate(II)pentahydratelight pink [11]
Mn[(C2O4)2Ni]•4H2Omanganese(II)bis(oxalato)nickelate(II)tetrahydratelight blue [12]
Cd[(C2O4)2Ni]•4H2Ocadmium(II)bis(oxalato)nickelate(II)tetrahydrateblue [11]

Because the Ni2+ ion resembles many other divalent metal ions, it can be substituted by them, or substitute for them in other oxalate compounds to form mixed oxalates where the proportions can vary continuously. For example, magnesium nickel oxalate dihydrate. [13]

Related Research Articles

Basic copper carbonate Chemical compound

Basic copper carbonate is a chemical compound, more properly called copper(II) carbonate hydroxide. It is an ionic compound consisting of the ions copper(II) Cu2+
, carbonate CO2−
, and hydroxide OH

Nickel(II) chloride Chemical compound

Nickel(II) chloride (or just nickel chloride), is the chemical compound NiCl2. The anhydrous salt is yellow, but the more familiar hydrate NiCl2·6H2O is green. Nickel(II) chloride, in various forms, is the most important source of nickel for chemical synthesis. The nickel chlorides are deliquescent, absorbing moisture from the air to form a solution. Nickel salts have been shown to be carcinogenic to the lungs and nasal passages in cases of long-term inhalation exposure.

Sodium oxalate Chemical compound

Sodium oxalate, or disodium oxalate, is the sodium salt of oxalic acid with the formula Na2C2O4. It is a white, crystalline, odorless solid, that decomposes above 290 °C.

Ammonium tetrathiomolybdate Chemical compound

Ammonium tetrathiomolybdate is the chemical compound with the formula (NH4)2MoS4. This bright red ammonium salt is an important reagent in the chemistry of molybdenum and has been used as a building block in bioinorganic chemistry. The thiometallate anion has the distinctive property of undergoing oxidation at the sulfur centers concomitant with reduction of the metal from Mo(VI) to Mo(IV).

Potassium ferrioxalate Chemical compound

Potassium ferrioxalate, also known as potassium trisoxalatoferrate or potassium tris(oxalato)ferrate(III) is a chemical compound with the formula K
]. It often occurs as the trihydrate K
. Both are crystalline compounds, lime green in colour.

Cobalt(II) oxalate Chemical compound

Cobalt(II) oxalate is the inorganic compound with the formula of CoC2O4. Like other simple inorganic oxalates, it is a coordination polymer. The oxalate ligands bridge of Co(OH2)2 centres. Each cobalt adopts octahedral coordination geometry.

Magnesium oxalate Magnesium compound

Magnesium oxalate is an organic compound comprising a magnesium cation with a 2+ charge bonded to an oxalate anion. It has the chemical formula MgC2O4. Magnesium oxalate is a white solid that comes in two forms: an anhydrous form and a dihydrate form where two water molecules are complexed with the structure. Both forms are practically insoluble in water and are insoluble in organic solutions.

Chromium(II) oxalate is an inorganic compound with the chemical formula CrC2O4.

Nickel(II) nitrite is an inorganic compound with the chemical formula Ni(NO2)2. Anhydrous nickel nitrite was first discovered in 1961 by Cyril Clifford Addison, who allowed gaseous nickel tetracarbonyl to react with dinitrogen tetroxide, yielding a green smoke. Nickel nitrite was the second transition element anhydrous nitrite discovered after silver nitrite.

Bismuth(III) nitrate Chemical compound

Bismuth(III) nitrate is a salt composed of bismuth in its cationic +3 oxidation state and nitrate anions. The most common solid form is the pentahydrate. It is used in the synthesis of other bismuth compounds. It is available commercially. It is the only nitrate salt formed by a group 15 element, indicative of bismuth's metallic nature.

Cyanonickelate Class of chemical compounds

The cyanonickelates are a class of chemical compound containing anions consisting of nickel atoms, and cyanide groups. The most important of these are the tetracyanonickelates containing four cyanide groups per nickel. The tetracyanonickelates contain the [Ni(CN)4]2− anion. This can exist in solution or in solid salts. The ion has cyanide groups arranged in a square around the central nickel ion. The symmetry of the ion is D4h. The distance from the nickel atom to the carbon is 1.87 Å, and the carbon-nitrogen distance is 1.16 Å. Tetracyanonickelate(II) can be oxidised electrochemically in solution to yield tetracyanonickelate(III) [Ni(CN)4]. [Ni(CN)4] is unstable and Ni(III) oxidises the cyanide to cyanate OCN. Tetracyanonickelate(III) can add two more cyanide groups to form hexacyanonickelate(III).

Compounds of nickel are chemical compounds containing the element nickel which is a member of the group 10 of the periodic table. Most compounds in the group have an oxidation state of +2. Nickel is classified as a transition metal with nickel(II) having much chemical behaviour in common with iron(II) and cobalt(II). Many salts of nickel(II) are isomorphous with salts of magnesium due to the ionic radii of the cations being almost the same. Nickel forms many coordination complexes. Nickel tetracarbonyl was the first pure metal carbonyl produced, and is unusual in its volatility. Metalloproteins containing nickel are found in biological systems.

The fluoronickelates are a class of chemical compounds containing an anion with nickel at its core, surrounded by fluoride ions which act as ligands. This makes it a fluoroanion. The nickel atom can be in a range of oxidation states from +2, +3 to +4. The hexafluoronickelate(IV)2− ion NiF62− contains nickel in the maximal +4 state, and is in octahedral coordination by the fluoride atoms. It forms a commercially available salt Potassium hexafluoronickelate(IV) K2NiF6. Solid double salts can also contain tetrafluoronickelate NiF4 eg K2NiF4.

The tetrabromonickelate anion contains a doubly-charged nickel atom (Ni2+) surrounded by four bromide ions in a tetrahedral arrangement. The formula is [NiBr4]2−.

Nickel succinate is a transition metal carboxylic acid salt. It crystallises in several forms. Nickel coordinates in a far more diverse way than other transition elements enabling a variety of structures for the same constituents. Succinate is dibasic, so its two ends can connect onto two different nickel atoms. Succininate is flexible, so that it can be bent to different angles and lengths. This allows formation of metal organic framework solids.

Chevreuls salt Chemical compound

Chevreul's salt (copper(I,II) sulfite dihydrate, Cu2SO3•CuSO3•2H2O or Cu3(SO3)2•2H2O), is a copper salt which was prepared for the first time by a French chemist Michel Eugène Chevreul in 1812. Its unusual property is that it contains copper in both of its common oxidation states. It is insoluble in water and stable in air. What was known as Rogojski's salt is a mixture of Chevreul's salt and metallic copper.

Caesium oxalate (standard IUPAC spelling) dicesium oxalate, or cesium oxalate (American spelling) is the oxalate of caesium. Caesium oxalate has the chemical formula of Cs2C2O4.

The nickel organic acid salts are organic acid salts of nickel. In many of these the ionised organic acid acts as a ligand.

Beryllium oxalate is an inorganic compound, a salt of beryllium metal and oxalic acid with the chemical formula C
. It forms colorless crystals, dissolves in water, and also forms crystalline hydrates. The compound is used to prepare ultra-pure beryllium oxide by thermal decomposition.

Transition metal oxalate complex

Transition metal oxalate complexes are coordination complexes with oxalate (C2O42−) ligands. Some are useful commercially, but the topic has attracted regular scholarly scrutiny. Oxalate (C2O42-) is a kind of dicarboxylate ligand. As a small, symmetrical dinegative ion, oxalate commonly forms five-membered MO2C2 chelate rings. Mixed ligand complexes are known, e.g., [Co(C2O4)(NH3)4]κ+.


  1. 1 2 Morrison, J.T.; Baker, W.A. (January 1969). "Nickel(II) complexes with oxygen and sulfur donors". Inorganica Chimica Acta. 3: 463–467. doi:10.1016/S0020-1693(00)92534-9.
  2. Macintyre, Jane E. (1997). Dictionary of Inorganic Compounds, Supplement 4. CRC Press. p. 453. ISBN   9780412750205 . Retrieved 21 April 2016.
  3. Saha, H.L.; Mitra, S. (June 1987). "Thermal decomposition reactions of metal carboxylato complexes in the solid state. III. Thermographic and differential thermal studies of metal oxalato, malonato and succinato complexes". Thermochimica Acta. 116: 53–64. doi:10.1016/0040-6031(87)88164-9.
  4. 1 2 Macintyre, Jane E. (1997). Dictionary of Inorganic Compounds, Supplement 4. CRC Press. p. 251. ISBN   9780412750205 . Retrieved 21 April 2016.
  5. Saha, H.L.; Mitra, S. (January 1987). "Thermal decomposition reactions of metal carboxylato complexes in the solid state. I. Thermographic and differential thermal studies of metal oxalato, malonato and succinato complexes". Thermochimica Acta. 109 (2): 331–342. doi:10.1016/0040-6031(87)80029-1.
  6. Saha, H.L.; Mitra, S. (March 1987). "Thermal decomposition reactions of metal carboxylato complexes in the solid state. II. Thermographic and differential thermal studies of metal oxalato, malonato and succinato complexes". Thermochimica Acta. 112 (2): 275–287. doi:10.1016/0040-6031(87)88284-9.
  7. Román, P.; Guzmán-Miralles, C.; Luque, A. (15 July 1993). "Structure of dipotassium trans-diaquabis(oxalato-O,O')nickelate(II)–water (1/4)" (PDF). Acta Crystallographica Section C. 49 (7): 1336–1339. doi:10.1107/S0108270193000940.
  8. Narsimhulu, M.; Raju, B.; Saritha, A.; Narayana Rao, D.; Hussain, K.A. (September 2015). "A new room-temperature ultraviolet emission material: ". Physica B: Condensed Matter. 472: 45–48. Bibcode:2015PhyB..472...45N. doi:10.1016/j.physb.2015.05.019.
  9. Macintyre, Jane E. (1993-07-15). Dictionary of Inorganic Compounds, Supplement 1. CRC Press. p. 45. ISBN   9780412490903 . Retrieved 25 April 2016.
  10. Macintyre, Jane E. (1997). Dictionary of Inorganic Compounds, Supplement 4. CRC Press. p. 222. ISBN   9780412750205 . Retrieved 21 April 2016.
  11. 1 2 Deb, Nidhuban; Baruah, S. D.; Dass, N. N. (2000). "Synthesis, Characterization and Thermal Decomposition of ( and )". Journal of Thermal Analysis and Calorimetry. 59 (3): 791–797. doi:10.1023/A:1010153720786. S2CID   94453246.
  12. Deb, Nidhuban (July 2005). "Thermal decomposition of manganese(II)bis(oxalato)nickelate(II)tetrahydrate". Journal of Thermal Analysis and Calorimetry. 81 (1): 61–65. doi:10.1007/s10973-005-0746-y. S2CID   94799986.
  13. Packter, A.; Omomo, A. (1984). "The coprecipitation of Magnesium Nickel Oxalate Dihydrate Powders (solid solutions) from aqueous solution: Precipitate compositions and Coprecipitate Mechanisms". Crystal Research and Technology. 19 (4): 467–476. doi:10.1002/crat.2170190406.