This page talks about various aspects of zero. Thanks to Alexey Radul for the ideas here; the research is mine.
PLT, MIT, Gambit, Chicken, Bigloo, Scheme48/scsh, Guile, SISC, Chez, Ikarus, Larceny, Mosh, Scheme 7, sscm, SXM, VSCM, and Chibi report an error.
Gauche, Kawa, SCM, Scheme 9 return inexact infinity.
PLT, MIT, Gambit, Chicken, Scheme48/scsh, Guile, Scheme 7, SXM, VSCM report an error.
Gauche, Bigloo, Kawa, SISC, Chez, Ikarus, Larceny, Mosh, Scheme 9 return inexact infinity.
SSCM does not handle inexact numbers.
Chicken, Scheme 7, SXM, VSCM report an error.
PLT, Gauche, Gambit, Bigloo, Scheme48/scsh, Guile, Kawa, SISC, Chez, SCM, Ikarus, Larceny, Mosh, Scheme 9, Chibi return inexact infinity.
SSCM does not handle inexact numbers.
PLT, MIT, Gambit, Guile, Chez, SXM return exact 0.
Gauche, Chicken, Bigloo, Scheme48/scsh, Kawa, SISC, SCM, Ikarus, Larceny, Mosh, Scheme 9, Scheme 7, VSCM, Chibi return inexact 0.0.
SSCM does not handle inexact numbers.
Gauche, MIT-Scheme, Chicken (with the numbers egg), Scheme48/scsh, Guile, Kawa, SISC, SCM, Scheme 7, VSCM consider 3.0+0.0i to be a real number.
PLT, Gambit, Chez, Ikarus, Larceny, Mosh do not.
Bigloo, Scheme 9, SSCM, SXM, Chibi do not implement general complex numbers.