Sodium pentaborate
Names | |
---|---|
Other names Sodium pentaborate | |
Identifiers | |
CAS Number |
|
3D model (JSmol) |
|
ECHA InfoCard | 100.031.371 |
EC Number |
|
PubChem CID |
|
UNII |
|
CompTox Dashboard (EPA) |
|
InChI
| |
| |
Properties | |
Chemical formula | Na+[B5O6(OH)4]− or Na+[B5O7(OH)2]−·H2O |
Molar mass | 241.06 g·mol−1 |
Appearance | Colorless crystalline solid |
Solubility in water | Soluble |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references |
Sodium pentaborate, more properly disodium decaborate, is a chemical compound of sodium, boron, and oxygen; a salt with elemental formula NaB5O8, Na2B10O16, or Na2O·5B2O3. It is a colorless crystalline solid, soluble in water.
The compound is often encountered or traded as hydrates NaB5O8·nH2O, Na2B10O16·2nH2O, or Na2O·5B2O3·2nH2O for n = 2,[1] 4,[2][3] 5,[4][5] or other values. This formula is often misleading as some of the water molecules are actually hydroxyl groups covalently attached to boron atoms.
The compound is used in agriculture as a boron supplement in fertilizer with various trade names such as Solubor[5] and Aquabor.[3] It has also been tested as an additive to improve plasma electrolytic oxidation of magnesium alloys.[4]
The name "sodium pentaborate" has also been used for a distinct compound with formula Na3B5O8·nH2O, better called trisodium pentaborate.[6]
Structure and preparation
Dihydrate
Sodium pentaborate "dihydrate" has the elemental formula NaH4B5O10, which can be parsed as NaB5O8·2H2O or Na2O·5B3O3·4H2O, however the correct formula seems to be either Na+[B5O6(OH)4]− or Na+[B5O7(OH)2]−·H2O. The latter seems more likely, since under thermogravimetric analysis the material starts to decompose at about 130 °C with partial loss of water. [1]
It can be prepared by reacting water solutions of sodium carbonate Na2CO3 and boric acid B(OH)3 in mole ratio 1:10 and evaporating the resulting solution at 40 °C. It belongs to the monoclinic crystal system with symmetry group P21/c (C2h5) and parameters a = 1110.3 pm, b = 1643.7 pm, c = 1356.4 pm, α = 89.960°, β = 112.850° and γ = 89.9°, formulas per cell Z = 4.[1]
References
- ^ a b c S. Stella Mary, S. Shahil Kirupavathy, P. Mythili, R. Gopalakrishnan (2008): "Growth and characterization of sodium pentaborate [Na(H4B5O10)] single crystals". Spectrochimica Acta Part A, volume 71, issue 4, 15 pages 1311-1316. doi:10.1016/j.saa.2008.04.021
- ^ M. Briggs (2001): "Boron Oxides, Boric Acid, and Borates". Chapter of the Kirk-Othmer Encyclopedia of Chemical Technology. Wiley.
- ^ a b "Aquabor 2 MSR". Product page in the Mineira Santa Rita company website. Accessed on 2022-06-27.
- ^ a b Taha Cagri Senocak, Taha Alper Yilmaz, Hasan Feyzi Budak, Gokhan Gulten, Ahmet Melik Yilmaz, Kadri Vefa Ezirmik, Yasar Totikc (2022): "Influence of sodium pentaborate (B5H10NaO13) additive in plasma electrolytic oxidation process on WE43 magnesium alloys". Materials Today Communications, volume 30, article 103157. doi:10.1016/j.mtcomm.2022.103157
- ^ a b "Solubor DF". Product page in the 20 Mule Team Borax company website. Accessed on 2022-06-27.
- ^ Silvio Menchetti and Cesare Sabelli (1977): "The crystal structure of synthetic sodium pentaborate monohydrate". Acta Crystallographica Section B, volume B33, pages 3730-3733. doi:10.1107/S0567740877011959
- v
- t
- e
H3BO3 | He | ||||||||||||||||||||
Li2B4O7 | Be | B | +(CO3) +(C2O4) | (NH4)3BO3 +NO3 | O | +F | Ne | ||||||||||||||
Na2[B4O5(OH)4]·8H2O NaBO2 NaBO3 Na3BO3 Na2B8O13 | Mg3(BO3)2 | AlBO3 | Si | -PO4 +PO4 | +S -SO4 +SO4 | +Cl | Ar | ||||||||||||||
K2B4O7•4H2O KB5O8•4H2O | Ca3(BO3)2 | ScBO3 | TiBO3 | -VO4 | Cr | Mn3(BO3)2 | Fe3(BO3)2 FeBO3 FeB(OH)4 | Co3(BO3)2 | Ni3(BO3)2 | Cu3(BO3)2 | Znx(BO3)x | GaBO3 -GaO4 | -GeO4 | -AsO4 | -SeO4 -SeO3 +Se | +Br | Kr | ||||
Rb3BO3 RbB11O16(OH)2 Rb[B5O6(OH)4]•2H2O | Sr3(BO3)2 | YBO3 | ZrB2O5 | Nb | Mo | Tc | Ru | Rh | Pd | Ag3BO3 | Cd3(BO3)2 | InBO3 | Sn | -SbBO4 | -TeO4 -TeO3 | +I | Xe | ||||
Cs3BO3 CsB5O8•4H2O | BaB2O4 | * | Lu3B5O12 | HfB2O5 | Ta | W | Re | Os | Ir | Pt | Au | Hg | Tl3BO3 | Pb3(BO3)2 | BiBO3 | Po | At | Rn | |||
Fr | Ra | ** | Lr | Rf | Db | Sg | Bh | Hs | Mt | Ds | Rg | Cn | Nh | Fl | Mc | Lv | Ts | Og | |||
* | LaB3O6 | CeB3O6 | Pr4B10O21 | NdBO3 | Pm | Sm | Eu | Gd | Tb | Dy4B6O15 Dy2B4O9 | Ho4B6O15 Ho2B4O9 | ErBO3 | Tm3B5O12 | Yb3B5O12 | |||||||
** | Ac | Th3(BO3)4 | Pa | U(BO3)2 | Np | Pu | Am | Cm | Bk | Cf[B6O8(OH)5] | Es | Fm | Md | No |