Nb–Sn system

116 accepted literature values from 2 paper(s) (experimental 56, model 59, unspecified 1); 3 calculated phase diagram(s).

Data: JSON · CSV · interactive explorer · interactive phase diagram · phases (9) · papers (bibliography) · Markdown

Accepted values by evidence class
Evidence class	Values
experimental	56
model	59
unspecified	1

Accepted values by property group
Property group	Values
invariant reaction	59
formation	42
mixing / partial	2
heat capacity / entropy / enthalpy	13

Calculated phase diagrams

Binary phase diagrams calculated with pycalphad 0.11.2 from the SGTE binary collection (Hallstedt 2025, CC BY 4.0). Evidence class: model.

Assessments with a calculated phase diagram
TDB file	Assessment	SHA-256	Links
NbSn-02Tof.tdb	C. Toffolon, C. Servant, J.C. Gachon, B. Sundman, J. Phase Equilib., 23, 134-39(2002). doi:10.1361/1054971023604071	`28d911b942daf4344c792e37b434cbcc8a7f9344e35efdfa3c5fd1394e84c9d3`	viewer · TDB · JSON
NbSn-17Laf.tdb	P. Lafaye, C. Toffolon-Masclet, J.-C. Crivello, J.-M. Joubert, Calphad, 57, 37-45(2017). doi:10.1016/j.calphad.2017.02.003	`fe83573ddf9ba2bf926745a0cadfc8e88b72a5d34a5563367364fb3dc273340f`	viewer · TDB · JSON
NbSn-98Tof.tdb	C. Toffolon, C. Servant, B. Sundman, J. Phase Equilib., 19, 479-85(1998). doi:10.1361/105497198770341978	`7c50a914635b9aafb7831a6dae73374552c7ac04f3f6dab1e4af748e9d95bb2f`	viewer · TDB · JSON

Calculated three-phase invariants (model, mole fraction of the second component)
TDB file	T (K)	Phases at the invariant
NbSn-02Tof.tdb	2425.38	BCC_A2 (x(Sn) 0.10891) + NB3SN_A15 (x(Sn) 0.19208) + LIQUID (x(Sn) 0.21995)
NbSn-02Tof.tdb	1184.18	NB3SN_A15 (x(Sn) 0.27418) + NB6SN5 (x(Sn) 0.45455) + LIQUID (x(Sn) 0.99785)
NbSn-02Tof.tdb	1184.18	NB3SN_A15 (x(Sn) 0.27418) + NB6SN5 (x(Sn) 0.45455) + LIQUID (x(Sn) 0.99785)
NbSn-02Tof.tdb	1141.38	NB6SN5 (x(Sn) 0.45455) + NBSN2_CB (x(Sn) 0.66667) + LIQUID (x(Sn) 0.99844)
NbSn-02Tof.tdb	1141.38	NB6SN5 (x(Sn) 0.45455) + NBSN2_CB (x(Sn) 0.66667) + LIQUID (x(Sn) 0.99844)
NbSn-02Tof.tdb	1141.38	NB6SN5 (x(Sn) 0.45455) + NBSN2_CB (x(Sn) 0.66667) + LIQUID (x(Sn) 0.99844)
NbSn-02Tof.tdb	1011.82	NB3SN_A15 (x(Sn) 0.26659) + NB6SN5 (x(Sn) 0.45455) + NBSN2_CB (x(Sn) 0.66667)
NbSn-02Tof.tdb	1011.82	NB3SN_A15 (x(Sn) 0.26658) + NB6SN5 (x(Sn) 0.45455) + NBSN2_CB (x(Sn) 0.66667)
NbSn-02Tof.tdb	1011.82	NB3SN_A15 (x(Sn) 0.26658) + NB6SN5 (x(Sn) 0.45455) + NBSN2_CB (x(Sn) 0.66667)
NbSn-02Tof.tdb	505.08	NBSN2_CB (x(Sn) 0.66667) + BCT_A5 (x(Sn) 1) + LIQUID (x(Sn) 1)
NbSn-17Laf.tdb	2394.29	BCC_A2 (x(Sn) 0.11474) + NB3SN_A15 (x(Sn) 0.15754) + LIQUID (x(Sn) 0.24532)
NbSn-17Laf.tdb	1296.88	NB3SN_A15 (x(Sn) 0.28474) + NB6SN5 (x(Sn) 0.45455) + LIQUID (x(Sn) 0.99201)
NbSn-17Laf.tdb	1296.88	NB3SN_A15 (x(Sn) 0.28474) + NB6SN5 (x(Sn) 0.45455) + LIQUID (x(Sn) 0.992)
NbSn-17Laf.tdb	1119.95	NB6SN5 (x(Sn) 0.45455) + NBSN2_CB (x(Sn) 0.66667) + LIQUID (x(Sn) 0.99705)
NbSn-17Laf.tdb	1119.95	NB6SN5 (x(Sn) 0.45455) + NBSN2_CB (x(Sn) 0.66667) + LIQUID (x(Sn) 0.99706)
NbSn-17Laf.tdb	1119.95	NB6SN5 (x(Sn) 0.45455) + NBSN2_CB (x(Sn) 0.66667) + LIQUID (x(Sn) 0.99706)
NbSn-17Laf.tdb	992.31	NB3SN_A15 (x(Sn) 0.27158) + NB6SN5 (x(Sn) 0.45455) + NBSN2_CB (x(Sn) 0.66667)
NbSn-17Laf.tdb	992.31	NB3SN_A15 (x(Sn) 0.27158) + NB6SN5 (x(Sn) 0.45455) + NBSN2_CB (x(Sn) 0.66667)
NbSn-17Laf.tdb	992.31	NB3SN_A15 (x(Sn) 0.27158) + NB6SN5 (x(Sn) 0.45455) + NBSN2_CB (x(Sn) 0.66667)
NbSn-17Laf.tdb	505.08	NBSN2_CB (x(Sn) 0.66667) + BCT_A5 (x(Sn) 1) + LIQUID (x(Sn) 1)
NbSn-98Tof.tdb	2405.15	BCC_A2 (x(Sn) 0.08825) + NB3SN_A15 (x(Sn) 0.14315) + LIQUID (x(Sn) 0.23811)
NbSn-98Tof.tdb	1189.48	NB3SN_A15 (x(Sn) 0.33288) + NB6SN5 (x(Sn) 0.44973) + LIQUID (x(Sn) 0.9967)
NbSn-98Tof.tdb	1103.43	NB6SN5 (x(Sn) 0.45124) + NBSN2_CB (x(Sn) 0.66667) + LIQUID (x(Sn) 0.99825)
NbSn-98Tof.tdb	1068.1	BCC_A2 (x(Sn) 0.02183) + NB3SN_A15 (x(Sn) 0.27686) + NB6SN5 (x(Sn) 0.44961)
NbSn-98Tof.tdb	1025.57	BCC_A2 (x(Sn) 0.01751) + NB6SN5 (x(Sn) 0.45012) + NBSN2_CB (x(Sn) 0.66667)
NbSn-98Tof.tdb	505.08	NBSN2_CB (x(Sn) 0.66667) + BCT_A5 (x(Sn) 1) + LIQUID (x(Sn) 1)

Convex hulls: Materials Project DFT hull · OQMD DFT hull · CALPHAD hull NbSn-02Tof · CALPHAD hull NbSn-98Tof

Invariant reactions (literature)

Invariant reactions reported in the literature for the Nb–Sn system (59)
T (K)	Reaction / phases	Compositions (mole fraction)	Class	Source	Location
2425.15	Nb3Sn <-> Nb(bcc) +L	Nb3Sn: Sn 0.1921; Nb(bcc): Sn 0.1089; L: Sn 0.2199	model	[1] Toffolon 2002	Table 2, p. 3, row 31 report
2406.15	Nb3Sn -> Nbbcc_A2 + L	Nb3Sn: Sn 0.25	experimental	[2] Toffolon 1998 cites ref. 64Vie	Table 5, p. 3, row 19 report
2406.15	Nb3Sn <-> Nb(bcc) +L	Nb3Sn: Nb 0.75, Sn 0.25	experimental	[1] Toffolon 2002 cites ref. 1964Vie	Table 2, p. 3, row 36 report
2403.15	Nb3Sn <-> Nb(bcc) +L	Nb3Sn: Nb 0.75, Sn 0.25	model	[1] Toffolon 2002 cites Toffolon 2002	Table 2, p. 3, row 32 report
2403.15	Nb3Sn -> Nbbcc_A2 + L	Nb3Sn: Sn 0.25	experimental	[2] Toffolon 1998 cites ref. 64Ell	Table 5, p. 3, row 18 report
2403.15	Nb3Sn -> Nbbcc_A2 + L	Nb3Sn: Sn 0.25	experimental	[2] Toffolon 1998 cites ref. 70Cha	Table 5, p. 3, row 21 report
2403.15	Nb3Sn -> Nbbcc_A2 + L	Nb3Sn: Sn 0.25	model	[2] Toffolon 1998	Table 5, p. 3, row 17 report
2403.15	Nb3Sn -> Nbbcc_A2 + L	Nb3Sn: Sn 0.25	experimental	[2] Toffolon 1998 cites ref. 82Sch	Table 5, p. 3, row 23 report
2403.15	Nb3Sn <-> Nb(bcc) +L	Nb3Sn: Nb 0.75, Sn 0.25	experimental	[1] Toffolon 2002 cites Schiffman 1982	Table 2, p. 3, row 34 report
2403.15	Nb3Sn -> Nbbcc_A2 + L	Nb3Sn: Sn 0.25	experimental	[2] Toffolon 1998 cites ref. 73Mat	Table 5, p. 3, row 22 report
2403.15	Nb3Sn <-> Nb(bcc) +L	Nb3Sn: Sn 0.19; Nb(bcc): Sn 0.1; L: Sn 0.2	experimental	[1] Toffolon 2002 cites Charlesworth 1970 doi	Table 2, p. 3, row 35 report
2403.15	Nb3Sn <-> Nb(bcc) +L	Nb3Sn: Sn 0.18; Nb(bcc): Sn 0.12; L: Sn 0.21	model	[1] Toffolon 2002 cites Massalski 1988	Table 2, p. 3, row 33 report
2253.15	Nb3Sn -> Nbbcc_A2 + L	Nb3Sn: Sn 0.25	experimental	[2] Toffolon 1998 cites ref. 65Vuc	Table 5, p. 3, row 20 report
1203.15	Nb6Sn5 <-> Nb3Sn +L	Nb6Sn5: Sn 0.45; Nb3Sn: Sn 0.25; L: Sn 0.99	experimental	[1] Toffolon 2002 cites J 1965	Table 2, p. 3, row 27 report
1203.15	Nb6Sn5 <-> Nb3Sn +L	Nb6Sn5: Sn 0.4545; Nb3Sn: Sn 0.26; L: Sn 0.99	experimental	[1] Toffolon 2002 cites Charlesworth 1970 doi	Table 2, p. 3, row 25 report
1198.15	Nb6Sn5 <-> Nb3Sn +L	Nb6Sn5: Nb 0.545455, Sn 0.454545; Nb3Sn: Nb 0.75, Sn 0.25	experimental	[1] Toffolon 2002 cites ref. 1964Ens	Table 2, p. 3, row 29 report
1193.15	Nb6Sn5 <-> Nb3Sn +L	Nb6Sn5: Sn 0.45; Nb3Sn: Sn 0.26; L: Sn 0.99	model	[1] Toffolon 2002 cites Massalski 1988	Table 2, p. 3, row 23 report
1193.15	Nb6Sn5 <-> Nb3Sn +L	Nb6Sn5: Sn 0.45; Nb3Sn: Sn 0.3; L: Sn 0.99	experimental	[1] Toffolon 2002 cites Cvietchnikov 1967	Table 2, p. 3, row 26 report
1193.15	Nb6Sn5 -> Nb3Sn + L	Nb6Sn5: Sn 0.454545; Nb3Sn: Sn 0.25	experimental	[2] Toffolon 1998 cites ref. 86Mas	Table 5, p. 3, row 16 report
1189.15	Nb6Sn5 -> Nb3Sn + L	Nb6Sn5: Sn 0.454545; Nb3Sn: Sn 0.25	model	[2] Toffolon 1998	Table 5, p. 3, row 15 report
1189.15	Nb6Sn5 <-> Nb3Sn +L	Nb6Sn5: Nb 0.545455, Sn 0.454545; Nb3Sn: Nb 0.75, Sn 0.25	model	[1] Toffolon 2002 cites Toffolon 2002	Table 2, p. 3, row 22 report
1188.15	Nb6Sn5 <-> Nb3Sn +L	Nb6Sn5: Nb 0.545455, Sn 0.454545; Nb3Sn: Nb 0.75, Sn 0.25	experimental	[1] Toffolon 2002 cites Ellis 1964 doi	Table 2, p. 3, row 28 report
1188.15	Nb6Sn5 <-> Nb3Sn +L	Nb6Sn5: Nb 0.545455, Sn 0.454545; Nb3Sn: Nb 0.75, Sn 0.25	experimental	[1] Toffolon 2002 cites Schadler 1964	Table 2, p. 3, row 30 report
1184.15	Nb6Sn5 <-> Nb3Sn +L	Nb6Sn5: Sn 0.4545; Nb3Sn: Sn 0.2742; L: Sn 0.9978	model	[1] Toffolon 2002	Table 2, p. 3, row 21 report
1178.15	Nb6Sn5 <-> Nb3Sn +L	Nb6Sn5: Sn 0.45; Nb3Sn: Sn 0.25; L: Sn 0.99	experimental	[1] Toffolon 2002 cites Matstakova 1973	Table 2, p. 3, row 24 report
1141.15	NbSn2 <-> Nb6Sn5 +L	NbSn2: Sn 0.6667; Nb6Sn5: Sn 0.4545; L: Sn 0.9984	model	[1] Toffolon 2002	Table 2, p. 3, row 12 report
1133.15	NbSn2 -> Nb6Sn5 + L	NbSn2: Sn 0.666667; Nb6Sn5: Sn 0.454545	experimental	[2] Toffolon 1998 cites ref. 73Mat	Table 5, p. 3, row 13 report
1133.15	NbSn2 <-> Nb6Sn5 +L	NbSn2: Sn 0.6667; Nb6Sn5: Sn 0.45; L: Sn 0.99	experimental	[1] Toffolon 2002 cites Matstakova 1973	Table 2, p. 3, row 15 report
1133.15	NbSn2 <-> Nb6Sn5 +L	NbSn2: Sn 0.6667; Nb6Sn5: Sn 0.45; L: Sn 0.99	experimental	[1] Toffolon 2002 cites Cvietchnikov 1967	Table 2, p. 3, row 17 report
1123.15	NbSn2 -> Nb6Sn5 + L	NbSn2: Sn 0.666667; Nb6Sn5: Sn 0.454545	experimental	[2] Toffolon 1998 cites ref. 64Ens	Table 5, p. 3, row 10 report
1118.15	NbSn2 <-> Nb6Sn5 +L	NbSn2: Sn 0.6667; Nb6Sn5: Sn 0.45; L: Sn 0.99	experimental	[1] Toffolon 2002 cites Charlesworth 1970 doi	Table 2, p. 3, row 16 report
1118.15	NbSn2 -> Nb6Sn5 + L	NbSn2: Sn 0.666667; Nb6Sn5: Sn 0.454545	experimental	[2] Toffolon 1998 cites ref. 70Cha	Table 5, p. 3, row 12 report
1113.15	NbSn2 <-> Nb6Sn5 +L	NbSn2: Sn 0.6667; Nb6Sn5: Sn 0.45; L: Sn 0.99	experimental	[1] Toffolon 2002 cites J 1965	Table 2, p. 3, row 18 report
1113.15	NbSn2 -> Nb6Sn5 + L	NbSn2: Sn 0.666667; Nb6Sn5: Sn 0.454545	experimental	[2] Toffolon 1998 cites ref. 65Vuc	Table 5, p. 3, row 11 report
1113.15	NbSn2 <-> Nb6Sn5 +L	NbSn2: Nb 0.333333, Sn 0.666667; Nb6Sn5: Nb 0.545455, Sn 0.454545	experimental	[1] Toffolon 2002 cites Schadler 1964	Table 2, p. 3, row 20 report
1108.15	NbSn2 <-> Nb6Sn5 +L	NbSn2: Sn 0.6667; Nb6Sn5: Sn 0.45; L: Sn 0.99	model	[1] Toffolon 2002 cites Massalski 1988	Table 2, p. 3, row 14 report
1108.15	NbSn2 -> Nb6Sn5 + L	NbSn2: Sn 0.666667; Nb6Sn5: Sn 0.454545	experimental	[2] Toffolon 1998 cites ref. 86Mas	Table 5, p. 3, row 14 report
1103.15	NbSn2 -> Nb6Sn5 + L	NbSn2: Sn 0.666667; Nb6Sn5: Sn 0.454545	model	[2] Toffolon 1998	Table 5, p. 3, row 8 report
1103.15	NbSn2 <-> Nb6Sn5 +L	NbSn2: Nb 0.333333, Sn 0.666667; Nb6Sn5: Nb 0.545455, Sn 0.454545	model	[1] Toffolon 2002 cites Toffolon 2002	Table 2, p. 3, row 13 report
1093.15	NbSn2 <-> Nb6Sn5 +L	NbSn2: Nb 0.333333, Sn 0.666667; Nb6Sn5: Nb 0.545455, Sn 0.454545	experimental	[1] Toffolon 2002 cites Ellis 1964 doi	Table 2, p. 3, row 19 report
1093.15	NbSn2 -> Nb6Sn5 + L	NbSn2: Sn 0.666667; Nb6Sn5: Sn 0.454545	experimental	[2] Toffolon 1998 cites ref. 64Ell	Table 5, p. 3, row 9 report
1088.15	NbSn2 +Nb3Sn <-> Nb6Sn5	NbSn2: Sn 0.6667; Nb3Sn: Sn 0.3; Nb6Sn5: Sn 0.45	experimental	[1] Toffolon 2002 cites Cvietchnikov 1967	Table 2, p. 3, row 11 report
1069.15	Nbbcc_A2 + Nb6Sn5 -> Nb3Sn	Nb6Sn5: Sn 0.454545; Nb3Sn: Sn 0.25	model	[2] Toffolon 1998	Table 5, p. 3, row 6 report
1048.15	Nbbcc_A2 + Nb6Sn5 -> Nb3Sn	Nb6Sn5: Sn 0.454545; Nb3Sn: Sn 0.25	experimental	[2] Toffolon 1998 cites ref. 86Mas	Table 5, p. 3, row 7 report
1026.15	Nbbcc_A2 + NbSn2 -> Nb6Sn5	NbSn2: Sn 0.666667; Nb6Sn5: Sn 0.454545	model	[2] Toffolon 1998	Table 5, p. 3, row 4 report
1023.15	NbSn2 +Nb3Sn <-> Nb6Sn5	NbSn2: Sn 0.6667; Nb3Sn: Sn 0.26; Nb6Sn5: Sn 0.45	model	[1] Toffolon 2002 cites ref. 1976Mas	Table 2, p. 3, row 10 report
1023.15	Nbbcc_A2 + NbSn2 -> Nb6Sn5	NbSn2: Sn 0.666667; Nb6Sn5: Sn 0.454545	experimental	[2] Toffolon 1998 cites ref. 86Mas	Table 5, p. 3, row 5 report
1012.15	NbSn2 +Nb3Sn <-> Nb6Sn5	NbSn2: Sn 0.6667; Nb3Sn: Sn 0.2666; Nb6Sn5: Sn 0.4545	model	[1] Toffolon 2002	Table 2, p. 3, row 9 report
505.25	NbSn2 + L -> Snbct_A5	NbSn2: Sn 0.666667; Snbct_A5: Sn 1	model	[2] Toffolon 1998	Table 5, p. 3, row 1 report
505.25	NbSn2 +L <-> Snbct_A5	NbSn2: Sn 0.6667; L: Sn 1; Snbct_A5: Sn 1	model	[1] Toffolon 2002 cites Toffolon 2002	Table 2, p. 3, row 2 report
505.15	NbSn2 +L <-> Snbct_A5	NbSn2: Nb 0.333333, Sn 0.666667	experimental	[1] Toffolon 2002 cites Kogan 1965	Table 2, p. 3, row 6 report
505.15	NbSn2 +L <-> Snbct_A5	NbSn2: Sn 0.6667; L: Sn 1; Snbct_A5: Sn 1	model	[1] Toffolon 2002	Table 2, p. 3, row 1 report
505.15	NbSn2 +L <-> Snbct_A5	NbSn2: Sn 0.6667; L: Sn 1; Snbct_A5: Sn 1	experimental	[1] Toffolon 2002 cites Cvietchnikov 1967	Table 2, p. 3, row 5 report
505.15	NbSn2 +L <-> Snbct_A5	NbSn2: Sn 0.6667; L: Sn 1; Snbct_A5: Sn 1	experimental	[1] Toffolon 2002 cites Matstakova 1973	Table 2, p. 3, row 3 report
505.05	NbSn2 +L <-> Snbct_A5	NbSn2: Sn 0.6667; L: Sn 1; Snbct_A5: Sn 1	experimental	[1] Toffolon 2002 cites Charlesworth 1970 doi	Table 2, p. 3, row 4 report
505.05	NbSn2 + L -> Snbct_A5	NbSn2: Sn 0.666667; Snbct_A5: Sn 1	unspecified	[2] Toffolon 1998 cites ref. 64Ell	Table 5, p. 3, row 2 report
505.05	NbSn2 +L <-> Snbct_A5	NbSn2: Nb 0.333333, Sn 0.666667	experimental	[1] Toffolon 2002 cites Ellis 1964 doi	Table 2, p. 3, row 8 report
503.15	NbSn2 +L <-> Snbct_A5	NbSn2: Sn 0.6667; L: Sn 1; Snbct_A5: Sn 1	experimental	[1] Toffolon 2002 cites J 1965	Table 2, p. 3, row 7 report
503.15	NbSn2 + L -> Snbct_A5	NbSn2: Sn 0.666667; Snbct_A5: Sn 1	experimental	[2] Toffolon 1998 cites ref. 65Vuc	Table 5, p. 3, row 3 report

Formation enthalpies

Literature values in kJ/mol-atom where the per-atom basis is known. DFT columns: the lowest-energy entry at the same composition (Materials Project 2026.04.13, OQMD v1.8; different energy references, never averaged), from dft_parity.json.

Enthalpies of formation, Nb–Sn system (37)
Phase	Compound	Value	T (K)	Class	MP DFT (kJ/mol-atom)	OQMD DFT (kJ/mol-atom)	Source	Location	Quote
Nb0.545Sn0.455		-22 kJ/mol-atom	298.15	model			[1] Toffolon 2002 cites ref. 1988Deb	Table 3, p. 3, row 1 report
Nb0.545Sn0.455		-17.983 kJ/mol-atom	1173	model			[1] Toffolon 2002	Table 3, p. 3, row 4 report
Nb0.545Sn0.455		-14.814 kJ/mol-atom	298.15	model			[1] Toffolon 2002	Table 3, p. 3, row 3 report
Nb0.545Sn0.455		-2.653 kJ/mol-atom	1173	model			[1] Toffolon 2002 cites Toffolon 2002	Table 3, p. 3, row 2 report
Nb3Sn		-32.06 kJ/mol (basis unstated) ± 1.97	860	experimental			[1] Toffolon 2002 cites Malets 1975	Table 1, p. 1, row 1 report
Nb3Sn		-32.06 kJ/mol (basis unstated) ± 1.97	860	experimental			[2] Toffolon 1998 cites ref. 75Mal	Table 1, p. 1, row 1 report
Nb3Sn		-32.06 kJ/mol (basis unstated) ± 1.97	860	experimental			[1] Toffolon 2002 cites Malets 1975	Table 1, p. 1, row 2 report
Nb3Sn	Nb3Sn	-18.307 kJ/mol-atom	860	model	-15.81 (mp-aaaaabza)	-18.84 (oqmd-17754)	[1] Toffolon 2002	Table 1, p. 1, row 11 report
Nb3Sn	Nb3Sn	-18.241 kJ/mol-atom	1273	model	-15.81 (mp-aaaaabza)	-18.84 (oqmd-17754)	[1] Toffolon 2002	Table 1, p. 1, row 12 report
Nb3Sn	Nb3Sn	-17.876 kJ/mol-atom	1473	model	-15.81 (mp-aaaaabza)	-18.84 (oqmd-17754)	[1] Toffolon 2002	Table 1, p. 1, row 13 report
Nb3Sn	Nb3Sn	-17.095 kJ/mol-atom	1623	model	-15.81 (mp-aaaaabza)	-18.84 (oqmd-17754)	[1] Toffolon 2002	Table 1, p. 1, row 14 report
Nb3Sn		-16.7 unspecified ± 1.8	1623.15	experimental			[1] Toffolon 2002	p. 3 report	Five experiments were carried out, and the average value of the enthalpy of formation of Nb3Sn at 1350 °C was equal to -16.7 ± 1.8 kJ/mol.
Nb3Sn		-16.7 kJ/mol (basis unstated) ± 1.8	1623	experimental			[1] Toffolon 2002	Table 1, p. 1, row 6 report
Nb3Sn		-16.57 kJ/mol (basis unstated)	298.15	experimental			[1] Toffolon 2002 cites Schiffman 1982	Table 1, p. 1, row 3 report
Nb3Sn		-16.57 kJ/mol (basis unstated)	298.15	experimental			[2] Toffolon 1998 cites ref. 82Sch	Table 1, p. 1, row 2 report
Nb3Sn	Nb3Sn	-16.564 kJ/mol-atom	298.15	model	-15.81 (mp-aaaaabza)	-18.84 (oqmd-17754)	[1] Toffolon 2002	Table 1, p. 1, row 10 report
Nb3Sn	Nb3Sn	-16.4 kJ/mol-atom	298.15	model	-15.81 (mp-aaaaabza)	-18.84 (oqmd-17754)	[1] Toffolon 2002 cites Miedema 1980 doi	Table 1, p. 1, row 7 report
Nb3Sn		-16.4 kJ/mol (basis unstated)	298.15	model			[2] Toffolon 1998 cites ref. 80Mie	Table 1, p. 1, row 4 report
Nb3Sn		-16.19 kJ/mol (basis unstated)	298.15	experimental			[1] Toffolon 2002 cites Schiffman 1982	Table 1, p. 1, row 4 report
Nb3Sn		-16.19 kJ/mol (basis unstated)	298.15	experimental			[2] Toffolon 1998 cites ref. 82Sch	Table 1, p. 1, row 3 report
Nb3Sn		-16 kJ/mol (basis unstated)	298.15	model			[2] Toffolon 1998 cites ref. 88Deb	Table 1, p. 1, row 5 report
Nb3Sn	Nb3Sn	-16 kJ/mol-atom	298.15	model	-15.81 (mp-aaaaabza)	-18.84 (oqmd-17754)	[1] Toffolon 2002 cites ref. 1988Deb	Table 1, p. 1, row 8 report
Nb3Sn		-15.2 kJ/mol (basis unstated) ± 2.3	1473	experimental			[1] Toffolon 2002 cites Meschel 1998 doi	Table 1, p. 1, row 5 report
Nb3Sn		2.768 kJ/mol (basis unstated)	1273	model			[2] Toffolon 1998	Table 1, p. 1, row 6 report
Nb3Sn	Nb3Sn	2.768 kJ/mol-atom	1273	model	-15.81 (mp-aaaaabza)	-18.84 (oqmd-17754)	[1] Toffolon 2002 cites Toffolon 2002	Table 1, p. 1, row 9 report
Nb6Sn5		-22 kJ/mol (basis unstated)	298.15	model			[2] Toffolon 1998 cites ref. 88Deb	Table 2, p. 1, row 1 report
Nb6Sn5		-2.653 kJ/mol (basis unstated)	1173	model			[2] Toffolon 1998	Table 2, p. 1, row 2 report
NbSn2	NbSn2	-20.143 kJ/mol-atom	860	model	-13.422 (mp-aaaaabog)	-19.065 (oqmd-17753)	[1] Toffolon 2002	Table 4, p. 3, row 6 report
NbSn2		-18.21 kJ/mol (basis unstated) ± 0.81	860	experimental			[2] Toffolon 1998 cites ref. 75Mal	Table 3, p. 2, row 1 report
NbSn2		-18.21 kJ/mol (basis unstated) ± 0.81	860	experimental			[1] Toffolon 2002 cites Malets 1975	Table 4, p. 3, row 1 report
NbSn2		-17.585 kJ/mol (basis unstated)	298.15	model			[2] Toffolon 1998	Table 3, p. 2, row 4 report
NbSn2	NbSn2	-17.585 kJ/mol-atom	860	model	-13.422 (mp-aaaaabog)	-19.065 (oqmd-17753)	[1] Toffolon 2002 cites Toffolon 2002	Table 4, p. 3, row 3 report
NbSn2		-17.585 kJ/mol (basis unstated)	860	model			[2] Toffolon 1998	Table 3, p. 2, row 3 report
NbSn2	NbSn2	-17.585 kJ/mol-atom	298.15	model	-13.422 (mp-aaaaabog)	-19.065 (oqmd-17753)	[1] Toffolon 2002 cites Toffolon 2002	Table 4, p. 3, row 4 report
NbSn2	NbSn2	-16 kJ/mol-atom	298.15	model	-13.422 (mp-aaaaabog)	-19.065 (oqmd-17753)	[1] Toffolon 2002 cites ref. 1988Deb	Table 4, p. 3, row 2 report
NbSn2		-16 kJ/mol (basis unstated)	298.15	model			[2] Toffolon 1998 cites ref. 88Deb	Table 3, p. 2, row 2 report
NbSn2	NbSn2	-15.495 kJ/mol-atom	298.15	model	-13.422 (mp-aaaaabog)	-19.065 (oqmd-17753)	[1] Toffolon 2002	Table 4, p. 3, row 5 report

Other properties

Formation (5)

Formation, Nb–Sn system
Property	Value	T (K)	Phases / composition	Class	Source	Location
Entropy of formation printed: ΔfS	-10.23 J/mol (basis unstated)/K	298.15	NbSn2 alloy: Sn 0.666667	model	[2] Toffolon 1998	Table 3, p. 2, row 4 report
Entropy of formation printed: ΔfS	-13.58 J/mol (basis unstated)/K ± 2.45	860	Nb3Sn alloy: Sn 0.25	experimental	[2] Toffolon 1998 cites ref. 75Mal	Table 1, p. 1, row 1 report
Entropy of formation printed: ΔfS	-6.87 J/mol (basis unstated)/K ± 0.93	860	NbSn2 alloy: Sn 0.666667	experimental	[2] Toffolon 1998 cites ref. 75Mal	Table 3, p. 2, row 1 report
Entropy of formation printed: ΔfS	-10.23 J/mol (basis unstated)/K	860	NbSn2 alloy: Sn 0.666667	model	[2] Toffolon 1998	Table 3, p. 2, row 3 report
Entropy of formation printed: ΔfS	5.18 J/mol (basis unstated)/K	1273	Nb3Sn alloy: Sn 0.25	model	[2] Toffolon 1998	Table 1, p. 1, row 6 report

Mixing / partial (2)

Mixing / partial, Nb–Sn system
Property	Value	T (K)	Phases / composition	Class	Source	Location	Quote
Entropy of mixing printed: ΔS experimental	-13.58 J/mol (basis unstated)/K ± 2.45	860	Nb3Sn alloy: Sn 0.25	experimental	[1] Toffolon 2002 cites Malets 1975	Table 1, p. 1, row 1 report
Entropy of mixing printed: ΔS experimental	-6.87 J/mol (basis unstated)/K ± 0.93	860	NbSn2 alloy: Sn 0.666667	experimental	[1] Toffolon 2002 cites Malets 1975	Table 4, p. 3, row 1 report

Heat capacity / entropy / enthalpy (13)

Heat capacity / entropy / enthalpy, Nb–Sn system
Property	Value	T (K)	Phases / composition	Class	Source	Location
Entropy printed: ΔSoptimization	-1.84 J/mol/at	298.15	Nb0.545Sn0.455 alloy: Sn 0.455	model	[1] Toffolon 2002	Table 3, p. 3, row 3 report
Entropy printed: ΔS optimization	-2.49 J/mol/at	298.15	Nb3Sn alloy: Sn 0.25	model	[1] Toffolon 2002	Table 1, p. 1, row 10 report
Entropy printed: ΔS optimization	-3.76 unknown	298.15	NbSn2 alloy: Sn 0.666667	model	[1] Toffolon 2002	Table 4, p. 3, row 5 report
Entropy printed: ΔS optimization	-10.23 unknown	298.15	NbSn2 alloy: Sn 0.666667	model	[1] Toffolon 2002 cites Toffolon 2002	Table 4, p. 3, row 4 report
Entropy printed: ΔS optimization	-5.95 J/mol/at	860	Nb3Sn alloy: Sn 0.25	model	[1] Toffolon 2002	Table 1, p. 1, row 11 report
Entropy printed: ΔS_experimental	-13.58 unknown ± 2.45	860	Nb3Sn alloy: Sn 0.25	experimental	[1] Toffolon 2002 cites Malets 1975	Table 1, p. 1, row 2 report
Entropy printed: ΔS optimization	-13 unknown	860	NbSn2 alloy: Sn 0.666667	model	[1] Toffolon 2002	Table 4, p. 3, row 6 report
Entropy printed: ΔS optimization	-10.23 unknown	860	NbSn2 alloy: Sn 0.666667	model	[1] Toffolon 2002 cites Toffolon 2002	Table 4, p. 3, row 3 report
Entropy printed: ΔSoptimization	-8.12 J/mol/at	1173	Nb0.545Sn0.455 alloy: Sn 0.455	model	[1] Toffolon 2002	Table 3, p. 3, row 4 report
Entropy printed: ΔS optimization	-5.89 J/mol/at	1273	Nb3Sn alloy: Sn 0.25	model	[1] Toffolon 2002	Table 1, p. 1, row 12 report
Entropy printed: ΔS optimization	5.18 J/mol/at	1273	Nb3Sn alloy: Sn 0.25	model	[1] Toffolon 2002 cites Toffolon 2002	Table 1, p. 1, row 9 report
Entropy printed: ΔS optimization	-5.63 J/mol/at	1473	Nb3Sn alloy: Sn 0.25	model	[1] Toffolon 2002	Table 1, p. 1, row 13 report
Entropy printed: ΔS optimization	-5.13 J/mol/at	1623	Nb3Sn alloy: Sn 0.25	model	[1] Toffolon 2002	Table 1, p. 1, row 14 report

Sources

Reporting papers the values were read from (a value cited from another work names that work in its row).

C. Toffolon, C. Servant, J. C. Gachon, B. Sundman, Reassessment of the Nb-Sn system, JPE 23, 134-139 (2002). doi:10.1361/1054971023604071
C. Toffolon, C. Servant, B. Sundman, Thermodynamic assessment of the Nb-Sn system, JPE 19, 479-485 (1998). doi:10.1361/105497198770341978

Please cite

R. Arróyave, J. Saal, D. Shin, ORCHID-Values: thermodynamic and phase-equilibrium values read from the literature (version 2026.10; Version 1, machine-extracted), Zenodo (2026). doi:10.5281/zenodo.23735569
R. Arróyave, J. Saal, D. Shin, ORCHID-Diagrams: calculated binary phase diagrams (version 2026.10), Zenodo (2026). doi:10.5281/zenodo.23735859
R. Arróyave, J. Saal, D. Shin, ORCHID-Hulls: binary convex hulls (Materials Project, OQMD, assessed CALPHAD) (version 2026.10), Zenodo (2026). doi:10.5281/zenodo.23735891
R. Arróyave, J. Saal, D. Shin, ORCHID data: umbrella record of the ORCHID datasets (version 2026.10; Version 1, machine-extracted), Zenodo (2026). doi:10.5281/zenodo.23736065

Also cite the original source of every value you use (paper_citation / paper_doi, and cited_dois for values the paper cites from earlier work); B. Hallstedt, The SGTE collection of binary datasets, Calphad 89 (2025) 102833, https://doi.org/10.1016/j.calphad.2025.102833 (CC BY 4.0), and the original assessment named in each file; A. Jain et al., The Materials Project: A materials genome approach to accelerating materials innovation, APL Materials 1 (2013) 011002, https://doi.org/10.1063/1.4812323 (CC BY 4.0); J. E. Saal et al., JOM 65 (2013) 1501, https://doi.org/10.1007/s11837-013-0755-4 and S. Kirklin et al., npj Comput. Mater. 1 (2015) 15010, https://doi.org/10.1038/npjcompumats.2015.10 (CC BY 4.0). Version 1, machine-extracted: values were read by language-model readers constrained to quote their source and checked automatically, and the release was then audited on the printed pages by adversarial audits, an independent second review of fit-facing records and a preliminary human review of a frozen sample. Flags such as accepted and ESPEI-ready record screening results, not certification; known issues are listed in the release notes.

@misc{orchid_literature_2026,
  author    = {Arr{\'o}yave, Raymundo and Saal, James and Shin, Dongwon},
  title     = {{ORCHID-Values: thermodynamic and phase-equilibrium values read from the literature}},
  version   = {2026.10},
  publisher = {Zenodo},
  year      = {2026},
  doi       = {10.5281/zenodo.23735569},
  url       = {https://doi.org/10.5281/zenodo.23735569},
  note      = {Version 1, machine-extracted}
}

@misc{orchid_phase_diagrams_2026,
  author    = {Arr{\'o}yave, Raymundo and Saal, James and Shin, Dongwon},
  title     = {{ORCHID-Diagrams: calculated binary phase diagrams}},
  version   = {2026.10},
  publisher = {Zenodo},
  year      = {2026},
  doi       = {10.5281/zenodo.23735859},
  url       = {https://doi.org/10.5281/zenodo.23735859}
}

@misc{orchid_hulls_2026,
  author    = {Arr{\'o}yave, Raymundo and Saal, James and Shin, Dongwon},
  title     = {{ORCHID-Hulls: binary convex hulls (Materials Project, OQMD, assessed CALPHAD)}},
  version   = {2026.10},
  publisher = {Zenodo},
  year      = {2026},
  doi       = {10.5281/zenodo.23735891},
  url       = {https://doi.org/10.5281/zenodo.23735891}
}

@misc{orchid_data_2026,
  author    = {Arr{\'o}yave, Raymundo and Saal, James and Shin, Dongwon},
  title     = {{ORCHID data: umbrella record of the ORCHID datasets}},
  version   = {2026.10},
  publisher = {Zenodo},
  year      = {2026},
  doi       = {10.5281/zenodo.23736065},
  url       = {https://doi.org/10.5281/zenodo.23736065},
  note      = {Version 1, machine-extracted}
}