Table 1.

Coefficients of linear thermal expansion α and operating temperatures T_oper of typical negative/low thermal expansion materials.

Materials	α (ppm K−1)	Toper (K)	Category	Methoda	References
β-eucryptite	−1 to −6b	300–900	1	D	[1, 4, 15]
α-ZrW2O8	−9	<425	1	D/N	[20]
β-ZrW2O8	−6	425–1030	1	D/N	[20]
Cd(CN)2	−33.5	170–375	1	X	[27]
ReO3	−0.5	<220	1	N	[10]
ReO3	−0.7	600–680	1b	N	[10]
(HfMg)(WO4)3	−2b	Room temp. ∼1070	1	D	[11]
Sm2.75C60	−100b	<30	2	X	[29]
Bi0.95La0.05NiO3	−82b	320∼380	2	D	[35]
Invar (Fe-36Ni)	0.1–1	<500	3	D	[37, 38]
Invar (Fe3Pt)	−6 to −30	100–420	3	D	[49, 50]
Tm2Fe16Cr	−9b	340–380	3	X	[47]
CuO nano particles	−36b	<150	3b	X	[48]
Mn3Cu0.53Ge0.47N	−16	265–340	3	D	[73]
Mn3Zn0.4Sn0.6N0.85C0.15	−23	270–335	3	D	[75]
Mn3Zn0.5Sn0.5N0.85C0.1B0.05	−30	280–340	3	D	[76]

^a D, dilatometry; N, neutron diffraction; X, x-ray diffraction.

^b The thermal expansion is anisotropic and α is the averaged value.

^c Details of the mechanism are unknown. The classification is temporary (see text).