Cluster bonding and energetics of the borane anions, BnHn2− (n = 5–12): A comparative study using bond length—bond enthal

C E HOUSECROFT, R SNAITH, K MOSS, Robert Mulvey, M E ONEILL, K WADE

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Abstract

Cluster bond enthalpies, EL(BB), and orders, n̄(BB), for the structurally characterised closo anions, BnHn2− (n = 6 and 8–12), have been estimated using the logarithmic length—enthalpy and enthalpy—order relationships EL(BB) (kJ mol−1) = 1.766 × 1011 [L(BB)]−4.0 and EL(BB) (kJ mol−1) = 318.8[n̄(BB)]0.697, respectively. In a parallel study, the molecular-orbital bond index CNDO-based calculation method has been used to give BB and BH bond indices, I(BB) and I(BH), from which bond index based bond enthalpies, EI, have been calculated using the relationships EI(BB) = 297.9 I(BB) and EI(BH) = 374.8I(BH) (enthalpies in kJ mol−1; lengths in pm). From these, total skeletal bond enthalpies Σ E(BB), and total bond enthalpies, Σ E(BB) + Σ E(BH), have been calculated. Although calculated values of EL and Σ EL generally exceed those of EI and Σ EI by some 8% and calculated values of I generally exceed those of n̄ by a greater amount, the trends in these parameters for the series of BnHn2− anions are very similar, showing the greater efficiency with which the n + 1 skeletal electron pairs are used as n increases. However, the two approaches differ in that, whereas the Σ EI values suggest that the anions are all of comparable stability, the ΣEL values clearly show B6H62−, B10H102− and B12H122− to be more stable than B8H82−, B9H92− and B11H112−. The interatomic distances in B7H72− and in the unknown B5 H52− are estimated and used to assess their relative stabilities. The EL values suggest that B7 H72− is of comparable stability to B8H82− etc., but show B5H52− as relatively unstable. The EI values suggest that both of these anions should be relatively stable members of the series of closo anions.
LanguageEnglish
Pages1875-1881
Number of pages7
JournalPolyhedron
Volume4
Issue number11
DOIs
Publication statusPublished - 1985

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Boranes
boranes
Bond length
Anions
Enthalpy
Negative ions
enthalpy
anions
Molecular orbitals
molecular orbitals
trends
Electrons

Keywords

  • cluster bonding
  • borane anions
  • closo anions
  • bond enthal

Cite this

HOUSECROFT, C E ; SNAITH, R ; MOSS, K ; Mulvey, Robert ; ONEILL, M E ; WADE, K . / Cluster bonding and energetics of the borane anions, BnHn2− (n = 5–12): A comparative study using bond length—bond enthal. In: Polyhedron. 1985 ; Vol. 4, No. 11. pp. 1875-1881.
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abstract = "Cluster bond enthalpies, EL(BB), and orders, n̄(BB), for the structurally characterised closo anions, BnHn2− (n = 6 and 8–12), have been estimated using the logarithmic length—enthalpy and enthalpy—order relationships EL(BB) (kJ mol−1) = 1.766 × 1011 [L(BB)]−4.0 and EL(BB) (kJ mol−1) = 318.8[n̄(BB)]0.697, respectively. In a parallel study, the molecular-orbital bond index CNDO-based calculation method has been used to give BB and BH bond indices, I(BB) and I(BH), from which bond index based bond enthalpies, EI, have been calculated using the relationships EI(BB) = 297.9 I(BB) and EI(BH) = 374.8I(BH) (enthalpies in kJ mol−1; lengths in pm). From these, total skeletal bond enthalpies Σ E(BB), and total bond enthalpies, Σ E(BB) + Σ E(BH), have been calculated. Although calculated values of EL and Σ EL generally exceed those of EI and Σ EI by some 8{\%} and calculated values of I generally exceed those of n̄ by a greater amount, the trends in these parameters for the series of BnHn2− anions are very similar, showing the greater efficiency with which the n + 1 skeletal electron pairs are used as n increases. However, the two approaches differ in that, whereas the Σ EI values suggest that the anions are all of comparable stability, the ΣEL values clearly show B6H62−, B10H102− and B12H122− to be more stable than B8H82−, B9H92− and B11H112−. The interatomic distances in B7H72− and in the unknown B5 H52− are estimated and used to assess their relative stabilities. The EL values suggest that B7 H72− is of comparable stability to B8H82− etc., but show B5H52− as relatively unstable. The EI values suggest that both of these anions should be relatively stable members of the series of closo anions.",
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Cluster bonding and energetics of the borane anions, BnHn2− (n = 5–12): A comparative study using bond length—bond enthal. / HOUSECROFT, C E ; SNAITH, R ; MOSS, K ; Mulvey, Robert; ONEILL, M E ; WADE, K .

In: Polyhedron, Vol. 4, No. 11, 1985, p. 1875-1881.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Cluster bonding and energetics of the borane anions, BnHn2− (n = 5–12): A comparative study using bond length—bond enthal

AU - HOUSECROFT, C E

AU - SNAITH, R

AU - MOSS, K

AU - Mulvey, Robert

AU - ONEILL, M E

AU - WADE, K

PY - 1985

Y1 - 1985

N2 - Cluster bond enthalpies, EL(BB), and orders, n̄(BB), for the structurally characterised closo anions, BnHn2− (n = 6 and 8–12), have been estimated using the logarithmic length—enthalpy and enthalpy—order relationships EL(BB) (kJ mol−1) = 1.766 × 1011 [L(BB)]−4.0 and EL(BB) (kJ mol−1) = 318.8[n̄(BB)]0.697, respectively. In a parallel study, the molecular-orbital bond index CNDO-based calculation method has been used to give BB and BH bond indices, I(BB) and I(BH), from which bond index based bond enthalpies, EI, have been calculated using the relationships EI(BB) = 297.9 I(BB) and EI(BH) = 374.8I(BH) (enthalpies in kJ mol−1; lengths in pm). From these, total skeletal bond enthalpies Σ E(BB), and total bond enthalpies, Σ E(BB) + Σ E(BH), have been calculated. Although calculated values of EL and Σ EL generally exceed those of EI and Σ EI by some 8% and calculated values of I generally exceed those of n̄ by a greater amount, the trends in these parameters for the series of BnHn2− anions are very similar, showing the greater efficiency with which the n + 1 skeletal electron pairs are used as n increases. However, the two approaches differ in that, whereas the Σ EI values suggest that the anions are all of comparable stability, the ΣEL values clearly show B6H62−, B10H102− and B12H122− to be more stable than B8H82−, B9H92− and B11H112−. The interatomic distances in B7H72− and in the unknown B5 H52− are estimated and used to assess their relative stabilities. The EL values suggest that B7 H72− is of comparable stability to B8H82− etc., but show B5H52− as relatively unstable. The EI values suggest that both of these anions should be relatively stable members of the series of closo anions.

AB - Cluster bond enthalpies, EL(BB), and orders, n̄(BB), for the structurally characterised closo anions, BnHn2− (n = 6 and 8–12), have been estimated using the logarithmic length—enthalpy and enthalpy—order relationships EL(BB) (kJ mol−1) = 1.766 × 1011 [L(BB)]−4.0 and EL(BB) (kJ mol−1) = 318.8[n̄(BB)]0.697, respectively. In a parallel study, the molecular-orbital bond index CNDO-based calculation method has been used to give BB and BH bond indices, I(BB) and I(BH), from which bond index based bond enthalpies, EI, have been calculated using the relationships EI(BB) = 297.9 I(BB) and EI(BH) = 374.8I(BH) (enthalpies in kJ mol−1; lengths in pm). From these, total skeletal bond enthalpies Σ E(BB), and total bond enthalpies, Σ E(BB) + Σ E(BH), have been calculated. Although calculated values of EL and Σ EL generally exceed those of EI and Σ EI by some 8% and calculated values of I generally exceed those of n̄ by a greater amount, the trends in these parameters for the series of BnHn2− anions are very similar, showing the greater efficiency with which the n + 1 skeletal electron pairs are used as n increases. However, the two approaches differ in that, whereas the Σ EI values suggest that the anions are all of comparable stability, the ΣEL values clearly show B6H62−, B10H102− and B12H122− to be more stable than B8H82−, B9H92− and B11H112−. The interatomic distances in B7H72− and in the unknown B5 H52− are estimated and used to assess their relative stabilities. The EL values suggest that B7 H72− is of comparable stability to B8H82− etc., but show B5H52− as relatively unstable. The EI values suggest that both of these anions should be relatively stable members of the series of closo anions.

KW - cluster bonding

KW - borane anions

KW - closo anions

KW - bond enthal

U2 - 10.1016/S0277-5387(00)86704-2

DO - 10.1016/S0277-5387(00)86704-2

M3 - Article

VL - 4

SP - 1875

EP - 1881

JO - Polyhedron

T2 - Polyhedron

JF - Polyhedron

SN - 0277-5387

IS - 11

ER -